Forge 1.19.3

Created a CreativeModeTabEvent to register creative mode tabs and populate entries per tab
Moved datapack registries to DataPackRegistryEvent.NewRegistry event instead of tying them to ForgeRegistry
Made it easier for mods to datagen datapack builtin entries with DatapackBuiltinEntriesProvider
Provided access to lookupProvider for datagen
Updated dependencies to match versions used by vanilla and update JarJar to 0.3.18
Added a test mod for the new CreativeModeTabEvent
Throws better error message for Forge registries in tag datagen
Deleted ForgeRegistryTagsProvider
Updated ClientChatReceivedEvent and ServerChatEvent for Mojang changes
Added patches for both sign related methods in ModelLayers
Changed RegisterShadersEvent to use ResourceProvider
Migrated old Mojang math types to JOML

Co-authored-by: Marc Hermans <[email protected]>
Co-authored-by: LexManos <[email protected]>
Co-authored-by: sciwhiz12 <[email protected]>
Co-authored-by: coehlrich <[email protected]>

.github/support.yml

@@ -1,16 +0,0 @@
-# Configuration for support-requests - https://github.com/dessant/support-requests
-
-# Label used to mark issues as support requests
-supportLabel: Forum
-# Comment to post on issues marked as support requests. Add a link
-# to a support page, or set to `false` to disable
-supportComment: >
-  👋 We use the issue tracker exclusively for final bug reports and feature requests.
-  However, this issue appears to be better suited for the
-  [Forge Support Forums](http://www.minecraftforge.net/forum/forum/18-support-bug-reports/).
-  Please create a new topic on the support forum with this issue, and the conversation can
-  continue there.
-# Whether to close issues marked as support requests
-close: true
-# Whether to lock issues marked as support requests
-lock: true

.github/workflows/spam-label.yml

@@ -0,0 +1,42 @@
+name: 'Spam label'
+
+on:
+  issues:
+    types: [labeled]
+  pull_request:
+    types: [labeled]
+  discussion:
+    types: [labeled]
+
+permissions:
+  contents: read
+  issues: write
+  pull-requests: write
+  discussions: write
+
+jobs:
+  lock:
+    if: ${{ (github.event.label.name == 'spam') && (github.event.action == 'labeled') }}
+    runs-on: ubuntu-latest
+    steps:
+      - uses: peter-evans/close-issue@v2
+        name: Close Issue
+        with: 
+          close-reason: 'not_planned'
+        if: ${{ github.event_name != 'pull_request' }}
+      - run: gh pr close ${{ github.event.pull_request.html_url }}
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        name: Close PR
+        if: ${{ github.event_name == 'pull_request' }}
+      - uses: maxkomarychev/[email protected]
+        name: Lock PR
+        if: ${{ github.event_name == 'pull_request' }}
+        with:
+          token: "${{ secrets.GITHUB_TOKEN }}"
+          issue_number: ${{ github.event.number }}
+      - uses: OSDKDev/[email protected]
+        with:
+          repo-token: "${{ secrets.GITHUB_TOKEN }}"
+        name: Lock issue
+        if: ${{ github.event_name != 'pull_request' }}

.github/workflows/support.yml

@@ -0,0 +1,27 @@
+name: Support Requests
+
+on:
+  issues:
+    types:
+    - labeled
+    - unlabeled
+    - reopened
+
+permissions:
+  issues: write
+
+jobs:
+  support:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: dessant/support-requests@v2
+      with:
+        support-label: Forum
+        issue-comment: >
+            :wave: We use the issue tracker exclusively for final bug reports and feature requests. 
+            However, this issue appears to be better suited for the 
+            [Forge Support Forums](https://forums.minecraftforge.net/) or 
+            [Forge Discord](https://discord.gg/UvedJ9m). Please create a new topic on the support forum
+            with this issue or ask in the `#tech-support` channel in the Discord server, and the 
+            conversation can continue there.
+        lock-issue: true

.gitignore

@@ -33,6 +33,7 @@
 /projects/**/*.launch
 /repo/
 src/generated/resources/.cache/
+src/generated_test/resources/.cache/
 
 #Patch rejects
 /patches-/

.teamcity/settings.kts

@@ -1,5 +1,7 @@
 import jetbrains.buildServer.configs.kotlin.v2019_2.*
 import jetbrains.buildServer.configs.kotlin.v2019_2.projectFeatures.githubIssues
+import jetbrains.buildServer.configs.kotlin.*
+import jetbrains.buildServer.configs.kotlin.v2019_2.buildSteps.gradle
 
 /*
 The settings script is an entry point for defining a TeamCity
@@ -30,11 +32,13 @@ project {
     buildType(Build)
     buildType(BuildSecondaryBranches)
     buildType(PullRequests)
+    buildType(PullRequestChecks)
+    buildType(PullRequestCompatibility)
 
     params {
         text("docker_jdk_version", "17", label = "Gradle version", description = "The version of the JDK to use during execution of tasks in a JDK.", display = ParameterDisplay.HIDDEN, allowEmpty = false)
-        text("docker_gradle_version", "7.4", label = "Gradle version", description = "The version of Gradle to use during execution of Gradle tasks.", display = ParameterDisplay.HIDDEN, allowEmpty = false)
-        text("git_main_branch", "1.18.x", label = "Git Main Branch", description = "The git main or default branch to use in VCS operations.", display = ParameterDisplay.HIDDEN, allowEmpty = false)
+        text("docker_gradle_version", "7.5.1", label = "Gradle version", description = "The version of Gradle to use during execution of Gradle tasks.", display = ParameterDisplay.HIDDEN, allowEmpty = false)
+        text("git_main_branch", "1.19.x", label = "Git Main Branch", description = "The git main or default branch to use in VCS operations.", display = ParameterDisplay.HIDDEN, allowEmpty = false)
         text("git_branch_spec", """
                 +:refs/heads/(main*)
                 +:refs/heads/(master*)
@@ -134,3 +138,71 @@ object PullRequests : BuildType({
         """.trimIndent()
     }
 })
+
+object PullRequestChecks : BuildType({
+    templates(AbsoluteId("MinecraftForge_BuildPullRequests"), AbsoluteId("MinecraftForge_SetupGradleUtilsCiEnvironmen"), AbsoluteId("MinecraftForge_BuildWithDiscordNotifications"), AbsoluteId("MinecraftForge_SetupProjectUsingGradle"))
+    id("MinecraftForge_MinecraftForge__PullRequestChecks")
+    name = "Pull Requests (Checks)"
+    description = "Checks pull requests for the project"
+
+    steps {
+        gradle {
+            name = "Check"
+            id = "RUNNER_10_Check"
+
+            tasks = "checkAll"
+            gradleParams = "--continue %gradle_custom_args%"
+            enableStacktrace = true
+            dockerImage = "%docker_gradle_image%"
+            dockerRunParameters = """
+                -v "/opt/cache/agent/gradle:/home/gradle/.gradle"
+                -v "/opt/cache/shared/gradle:/home/gradle/rocache:ro"
+                --network=host
+                -u 1000:1000
+                %docker_additional_args%
+            """.trimIndent()
+        }
+    }
+
+    vcs {
+        branchFilter = """
+            +:*
+            -:1.*
+            -:<default>
+        """.trimIndent()
+    }
+})
+
+object PullRequestCompatibility : BuildType({
+    templates(AbsoluteId("MinecraftForge_BuildPullRequests"), AbsoluteId("MinecraftForge_SetupGradleUtilsCiEnvironmen"), AbsoluteId("MinecraftForge_BuildWithDiscordNotifications"), AbsoluteId("MinecraftForge_SetupProjectUsingGradle"))
+    id("MinecraftForge_MinecraftForge__PullRequestCompatibility")
+    name = "Pull Requests (Compatibility)"
+    description = "Validates binary compatibility for pull requests made to the project"
+
+    steps {
+        gradle {
+            name = "Validate"
+            id = "RUNNER_10_Compatibility"
+
+            tasks = "checkJarCompatibility"
+            gradleParams = "--continue %gradle_custom_args%"
+            enableStacktrace = true
+            dockerImage = "%docker_gradle_image%"
+            dockerRunParameters = """
+                -v "/opt/cache/agent/gradle:/home/gradle/.gradle"
+                -v "/opt/cache/shared/gradle:/home/gradle/rocache:ro"
+                --network=host
+                -u 1000:1000
+                %docker_additional_args%
+            """.trimIndent()
+        }
+    }
+
+    vcs {
+        branchFilter = """
+            +:*
+            -:1.*
+            -:<default>
+        """.trimIndent()
+    }
+})

LICENSE-header.txt

@@ -1,2 +1,2 @@
-Minecraft Forge - Forge Development LLC
+Copyright (c) Forge Development LLC and contributors
 SPDX-License-Identifier: LGPL-2.1-only

build.gradle

@@ -1,14 +1,3 @@
-buildscript {
-    repositories {
-        mavenLocal()
-        maven { url = 'https://maven.minecraftforge.net/' }
-        mavenCentral()
-    }
-    dependencies {
-        classpath 'net.minecraftforge.gradle:ForgeGradle:[5.1.26,)'
-    }
-}
-
 import groovy.json.JsonBuilder
 
 import java.nio.file.Files
@@ -17,6 +6,7 @@ import java.util.LinkedHashMap
 import net.minecraftforge.forge.tasks.*
 import static net.minecraftforge.forge.tasks.Util.*
 import net.minecraftforge.gradle.common.tasks.ApplyBinPatches
+import net.minecraftforge.gradle.common.tasks.CheckJarCompatibility
 import net.minecraftforge.gradle.common.tasks.DownloadMavenArtifact
 import net.minecraftforge.gradle.common.tasks.ExtractInheritance
 import net.minecraftforge.gradle.common.tasks.SignJar
@@ -29,7 +19,9 @@ plugins {
     id 'com.github.ben-manes.versions' version '0.36.0'
     id 'net.minecraftforge.gradleutils' version '2.+'
     id 'eclipse'
-    id 'de.undercouch.download' version '4.1.2'
+    id 'de.undercouch.download' version '5.1.3'
+    id 'net.minecraftforge.gradle.patcher' version '[5.1.50,5.2.0)' apply false
+    id 'net.minecraftforge.gradle.mcp' version '[5.1.50,5.2.0)' apply false
 }
 
 Util.init() //Init all our extension methods!
@@ -44,31 +36,48 @@ ext {
         ]
     }
     MAPPING_CHANNEL = 'official'
-    MAPPING_VERSION = '1.18.2'
-    MC_VERSION = '1.18.2'
-    MCP_VERSION = '20220228.144236'
-    SPI_VERSION = '4.0.10'
+    MAPPING_VERSION = '1.19.3'
+    MC_VERSION = '1.19.3'
+    MC_NEXT_VERSION = '1.20'
+    MCP_VERSION = '20221207.122022'
+    SPI_VERSION = '6.0.0'
     ACCESSTRANSFORMERS_VERSION = '8.0.4'
     COREMODS_VERSION = '5.0.1'
-    EVENTBUS_VERSION = '5.0.3'
-    MODLAUNCHER_VERSION = '9.1.3'
-    SECUREJARHANDLER_VERSION = '1.0.3'
-    BOOTSTRAPLAUNCHER_VERSION = '1.0.0'
-    ASM_VERSION = '9.2'
+    EVENTBUS_VERSION = '6.0.3'
+    MODLAUNCHER_VERSION = '10.0.8'
+    SECUREJARHANDLER_VERSION = '2.1.4'
+    BOOTSTRAPLAUNCHER_VERSION = '1.1.2'
+    ASM_VERSION = '9.3'
     INSTALLER_VERSION = '2.1.+'
     MIXIN_VERSION = '0.8.5'
+    TERMINALCONSOLEAPPENDER_VERSION = '1.2.0'
+    JLINE_VERSION = '3.12.+'
+    NIGHTCONFIG_VERSION = '3.6.4'
+    JETBRAINS_ANNOTATIONS_VERSION = '23.0.0'
+    SLF4J_API_VERSION = '1.8.0-beta4'
+    APACHE_MAVEN_ARTIFACT_VERSION = '3.8.5'
+    JARJAR_VERSION = '0.3.18'
+
+    // These versions should be kept in sync with the version manifest JSON
+    // To use a version newer than the version manifest JSON, the dependency must be added to the installer configuration
+    MOJANG_LOGGING_VERSION = '1.1.1'
+    LOG4J_VERSION = '2.19.0'
+    GUAVA_VERSION = '31.1-jre'
+    GSON_VERSION = '2.10'
+    APACHE_COMMONS_LANG3_VERSION = '3.12.0'
+    JOPT_SIMPLE_VERSION = '5.0.4'
+    COMMONS_IO_VERSION = '2.11.0'
 
     GIT_INFO = gradleutils.gitInfo
     VERSION = gradleutils.getFilteredMCTagOffsetBranchVersion(true, '[0-9]', MC_VERSION)
     // FML_VERSION = gradleutils.getFilteredMCTagOffsetBranchVersion(true, 'FML', MC_VERSION)
     FORGE_VERSION = VERSION.substring(MC_VERSION.length() + 1)
 
-    SPECIAL_SOURCE = 'net.md-5:SpecialSource:1.10.0'
-    BINPATCH_TOOL = 'net.minecraftforge:binarypatcher:1.0.12:fatjar'
-    INSTALLER_TOOLS = 'net.minecraftforge:installertools:1.2.10'
+    BINPATCH_TOOL = 'net.minecraftforge:binarypatcher:1.1.1:fatjar'
+    INSTALLER_TOOLS = 'net.minecraftforge:installertools:1.3.0'
     JAR_SPLITTER = 'net.minecraftforge:jarsplitter:1.1.4'
-    FART = 'net.minecraftforge:ForgeAutoRenamingTool:0.1.17:all'
-    MIN_TAG_FOR_CHANGELOG = "39.0"
+    FART = 'net.minecraftforge:ForgeAutoRenamingTool:0.1.22:all'
+    MIN_TAG_FOR_CHANGELOG = '41.0'
 }
 
 println('Version: ' + VERSION +
@@ -87,7 +96,7 @@ def extraTxts = [
 ]
 
 task downloadVersionManifest(type: Download) {
-    src 'https://launchermeta.mojang.com/mc/game/version_manifest_v2.json'
+    src 'https://piston-meta.mojang.com/mc/game/version_manifest_v2.json'
     dest file('build/versions/version_manifest.json')
     useETag 'all'
     onlyIfModified true
@@ -136,6 +145,10 @@ subprojects {
             name = 'forge'
             url = 'https://maven.minecraftforge.net/'
         }
+        maven {
+            name = 'minecraft'
+            url = 'https://libraries.minecraft.net/'
+        }
     }
 
     java.toolchain.languageVersion = JavaLanguageVersion.of(17)
@@ -249,6 +262,7 @@ def sharedDeps = {
     moduleonly "org.ow2.asm:asm-util:${ASM_VERSION}"
     moduleonly "org.ow2.asm:asm-analysis:${ASM_VERSION}"
     moduleonly "cpw.mods:bootstraplauncher:${BOOTSTRAPLAUNCHER_VERSION}"
+    moduleonly "net.minecraftforge:JarJarFileSystems:${JARJAR_VERSION}"
 
     installer "cpw.mods:securejarhandler:${SECUREJARHANDLER_VERSION}"
     installer "org.ow2.asm:asm:${ASM_VERSION}"
@@ -257,21 +271,23 @@ def sharedDeps = {
     installer "org.ow2.asm:asm-util:${ASM_VERSION}"
     installer "org.ow2.asm:asm-analysis:${ASM_VERSION}"
     installer "net.minecraftforge:accesstransformers:${ACCESSTRANSFORMERS_VERSION}"
-    installer 'org.antlr:antlr4-runtime:4.9.1' //Dep of AccessTransformer
+    installer 'org.antlr:antlr4-runtime:4.9.1' // Dep of AccessTransformer
     installer "net.minecraftforge:eventbus:${EVENTBUS_VERSION}"
     installer "net.minecraftforge:forgespi:${SPI_VERSION}"
     installer "net.minecraftforge:coremods:${COREMODS_VERSION}"
     installer "cpw.mods:modlauncher:${MODLAUNCHER_VERSION}"
     installer 'net.minecraftforge:unsafe:0.2.+'
-    installer 'com.electronwill.night-config:core:3.6.4'
-    installer 'com.electronwill.night-config:toml:3.6.4'
-    installer 'org.apache.maven:maven-artifact:3.6.3'
+    installer "com.electronwill.night-config:core:${NIGHTCONFIG_VERSION}"
+    installer "com.electronwill.night-config:toml:${NIGHTCONFIG_VERSION}"
+    installer "org.apache.maven:maven-artifact:${APACHE_MAVEN_ARTIFACT_VERSION}"
     installer 'net.jodah:typetools:0.8.3'
-    installer 'net.minecrell:terminalconsoleappender:1.2.0'
-    installer 'org.jline:jline-reader:3.12.+'   //Dep of TerminaalConsoleeAppender
-    installer 'org.jline:jline-terminal:3.12.+' //Dep of TerminaalConsoleeAppender
+    installer "net.minecrell:terminalconsoleappender:${TERMINALCONSOLEAPPENDER_VERSION}"
+    installer "org.jline:jline-reader:${JLINE_VERSION}"   // Dep of TerminalConsoleAppender
+    installer "org.jline:jline-terminal:${JLINE_VERSION}" // Dep of TerminalConsoleAppender
     installer "org.spongepowered:mixin:${MIXIN_VERSION}"
     installer 'org.openjdk.nashorn:nashorn-core:15.3'
+    installer "net.minecraftforge:JarJarSelector:${JARJAR_VERSION}"
+    installer "net.minecraftforge:JarJarMetadata:${JARJAR_VERSION}"
 
     /*
     installer 'org.lwjgl:lwjgl:3.2.2'
@@ -364,7 +380,8 @@ def sharedFmlonlyForge = { Project prj ->
                 environment 'MOD_CLASSES', '{source_roots}'
                 environment 'MCP_MAPPINGS', '{mcp_mappings}'
 
-                property 'nativesDirectory', '{natives}'
+                // Natives are loaded from the classpath now in all cases
+                // property 'nativesDirectory', '{natives}'
                 if (prj.name == 'forge') {
                     property 'forge.enableGameTest', 'true'
                 }
@@ -418,6 +435,8 @@ def sharedFmlonlyForge = { Project prj ->
         run.args '--fml.forgeGroup', prj.group
         run.args '--fml.mcpVersion', MCP_VERSION
 
+        run.jvmArgs '-Djava.net.preferIPv6Addresses=system'
+
         if (run.name.contains('client')) {
             run.client true
         } else {
@@ -425,8 +444,9 @@ def sharedFmlonlyForge = { Project prj ->
         }
 
         // SecureJarHandler bootstrap values.
-        run.property 'ignoreList', prj.configurations.moduleonly.files.collect {it.name.replaceAll(/([-_]([.\d]*\d+)|\.jar$)/, '') }.join(',') + ",client-extra,fmlcore,javafmllanguage,mclanguage,${prj.name}-"
-        //run.property 'mergeModules', 'jna-5.10.0.jar,jna-platform-5.10.0.jar,java-objc-bridge-1.0.0.jar'
+        run.property 'ignoreList', prj.configurations.moduleonly.files.collect {it.name.replaceAll(/([-_]([.\d]*\d+)|\.jar$)/, '') }.join(',') + ",client-extra,fmlcore,javafmllanguage,lowcodelanguage,mclanguage,${prj.name}-"
+        // FIXME: Without this jna doesn't work at runtime. Someone figure out why please?
+        run.property 'mergeModules', 'jna-5.10.0.jar,jna-platform-5.10.0.jar'
         if (userdevRuns.contains(run)) {
             run.property 'legacyClassPath.file', '{minecraft_classpath_file}'
             run.jvmArgs '-p', '{modules}'
@@ -435,7 +455,9 @@ def sharedFmlonlyForge = { Project prj ->
             run.jvmArgs '-p', prj.configurations.moduleonly.files.collect { it.path }.join(File.pathSeparator)
         }
         run.jvmArgs '--add-modules', 'ALL-MODULE-PATH'
+        // Additions to these JVM module args should be mirrored to server_files/args.txt and other similar blocks in the buildscript
         run.jvmArgs '--add-opens', 'java.base/java.util.jar=cpw.mods.securejarhandler'
+        run.jvmArgs '--add-opens', 'java.base/java.lang.invoke=cpw.mods.securejarhandler'
         run.jvmArgs '--add-exports', 'java.base/sun.security.util=cpw.mods.securejarhandler'
         run.jvmArgs '--add-exports', 'jdk.naming.dns/com.sun.jndi.dns=java.naming'
     }
@@ -444,7 +466,8 @@ def sharedFmlonlyForge = { Project prj ->
         run.workingDirectory prj.file('run')
 
         if (run.name.contains('client') || run.name.contains('data')) {
-            run.property 'nativesDirectory', prj.extractNatives.output.get().asFile
+            // Natives are loaded from the classpath now in all cases
+            // run.property 'nativesDirectory', prj.extractNatives.output.get().asFile
             run.args '--assetsDir', prj.downloadAssets.output
             run.args '--assetIndex', "{asset_index}"
         }
@@ -484,7 +507,7 @@ def sharedFmlonlyForge = { Project prj ->
             IGNORE_LIST: Util.getArtifacts(prj, prj.configurations.moduleonly, false).values().collect{it.downloads.artifact.path.rsplit('/', 1)[1]}.join(','),
             MODULES: 'ALL-MODULE-PATH'
     ]
-    
+
     prj.task([dependsOn: rootProject.downloadServerRaw], 'makeClasspathFiles') {
         doLast {
             def CLASS_PATH = Util.getArtifacts(prj, prj.configurations.installer, false).values().collect{"libraries/${it.downloads.artifact.path}"} +
@@ -537,7 +560,7 @@ project(':fmlonly') {
 
     ext {
         MCP_ARTIFACT = project(':mcp').mcp.config.get()
-        PACKED_DEPS = [':fmlcore:jar', ':fmlloader:jar', ':javafmllanguage:jar', ':mclanguage:jar']
+        PACKED_DEPS = [':fmlcore:jar', ':fmlloader:jar', ':javafmllanguage:jar', ':lowcodelanguage:jar', ':mclanguage:jar']
         MAVEN_PATH = "${group.replace('.', '/')}/${project.name}/${VERSION}"
     }
 
@@ -566,6 +589,7 @@ project(':fmlonly') {
         implementation project(':fmlcore')
         implementation project(':fmlloader')
         implementation project(':javafmllanguage')
+        implementation project(':lowcodelanguage')
         implementation project(':mclanguage')
         runtimeOnly "cpw.mods:bootstraplauncher:${BOOTSTRAPLAUNCHER_VERSION}"
     }
@@ -619,11 +643,13 @@ project(':fmlonly') {
                            '--fml.forgeGroup', project.group,
                            '--fml.mcpVersion', MCP_VERSION],
                     jvm: ["-DignoreList=${fmlonly_client.properties.ignoreList},\${version_name}.jar",
-                          //"-DmergeModules=${fmlonly_client.properties.mergeModules}",
+                          "-DmergeModules=${fmlonly_client.properties.mergeModules}",
                           '-DlibraryDirectory=${library_directory}',
                           '-p', Util.getArtifacts(project, configurations.moduleonly, false).values().collect{"\${library_directory}/${it.downloads.artifact.path}"}.join('${classpath_separator}'),
                           '--add-modules', 'ALL-MODULE-PATH',
+                          // Additions to these JVM module args should be mirrored to server_files/args.txt and other similar blocks in the buildscript
                           '--add-opens', 'java.base/java.util.jar=cpw.mods.securejarhandler',
+                          '--add-opens', 'java.base/java.lang.invoke=cpw.mods.securejarhandler',
                           '--add-exports', 'java.base/sun.security.util=cpw.mods.securejarhandler',
                           '--add-exports', 'jdk.naming.dns/com.sun.jndi.dns=java.naming'
                     ]
@@ -842,7 +868,7 @@ project(':fmlonly') {
     }
 
     // Since we need the modules in the bootstrap, we need to make sure they are compiled before we do each run
-    afterEvaluate { prepareRuns.dependsOn(':fmlcore:jar', ':fmlloader:jar', ':javafmllanguage:jar', ':mclanguage:jar') }
+    afterEvaluate { prepareRuns.dependsOn(PACKED_DEPS) }
 }
 
 project(':forge') {
@@ -891,7 +917,7 @@ project(':forge') {
         // Essentially, the same as the old, except dropping the first number, and the builds are no longer unique.
         MCP_ARTIFACT = project(':mcp').mcp.config.get()
         VERSION_JSON = project(':mcp').file('build/mcp/downloadJson/version.json')
-        PACKED_DEPS = [':fmlcore:jar', ':fmlloader:jar', ':javafmllanguage:jar', ':mclanguage:jar']
+        PACKED_DEPS = [':fmlcore:jar', ':fmlloader:jar', ':javafmllanguage:jar', ':lowcodelanguage:jar', ':mclanguage:jar']
         MAVEN_PATH = "${group.replace('.', '/')}/${project.name}/${VERSION}"
     }
 
@@ -912,6 +938,7 @@ project(':forge') {
         implementation project(':fmlcore')
         implementation project(':fmlloader')
         implementation project(':javafmllanguage')
+        implementation project(':lowcodelanguage')
         implementation project(':mclanguage')
         runtimeOnly "cpw.mods:bootstraplauncher:${BOOTSTRAPLAUNCHER_VERSION}"
     }
@@ -1039,6 +1066,11 @@ project(':forge') {
                             '--mod', 'custom_tag_types_test',
                             '--mod', 'new_model_loader_test',
                             '--mod', 'remove_tag_datagen_test',
+                            '--mod', 'tag_based_tool_types',
+                            '--mod', 'custom_transformtype_test',
+                            '--mod', 'data_pack_registries_test',
+                            '--mod', 'biome_modifiers_test',
+                            '--mod', 'structure_modifiers_test',
                             '--output', rootProject.file('src/generated_test/resources/'),
                             '--existing', sourceSets.main.resources.srcDirs[0],
                             '--existing', sourceSets.test.resources.srcDirs[0]
@@ -1052,7 +1084,8 @@ project(':forge') {
             '/': [
                 'Timestamp': new Date().format("yyyy-MM-dd'T'HH:mm:ssZ"),
                 'GitCommit': gradleutils.gitInfo.abbreviatedId,
-                'Git-Branch': gradleutils.gitInfo.branch
+                'Git-Branch': gradleutils.gitInfo.branch,
+                'FML-System-Mods': 'forge'
             ] as LinkedHashMap,
             'net/minecraftforge/versions/forge/': [
                 'Specification-Title':      'Forge',
@@ -1111,6 +1144,7 @@ project(':forge') {
 
     task extractInheritance(type: ExtractInheritance, dependsOn: [genJoinedBinPatches, downloadLibraries]) {
         tool = INSTALLER_TOOLS + ':fatjar'
+        args.add '--annotations'
         input = genJoinedBinPatches.cleanJar
         libraries.addAll downloadLibraries.librariesOutput.map { rf -> Files.readAllLines(rf.asFile.toPath()).stream().map(File::new).collect(java.util.stream.Collectors.toList()) }
     }
@@ -1150,8 +1184,6 @@ project(':forge') {
         excs.from patcher.excs
     }
 
-    task checkAll(dependsOn: [checkATs, checkSAS, checkExcs, findFieldInstanceChecks]){}
-
     task checkPatchesAndFix(type: CheckPatches, dependsOn: genPatches) {
         patchDir = file("$rootDir/patches")
         autoFix = true
@@ -1168,6 +1200,51 @@ project(':forge') {
         lineEnding = '\n'
     }
 
+    def baseForgeVersionProperty = project.objects.property(String)
+    baseForgeVersionProperty.set(project.provider { getLatestForgeVersion(MC_VERSION) }.map { MC_VERSION + '-' + it })
+    baseForgeVersionProperty.finalizeValueOnRead()
+    def jarCompatibilityTaskSetup = { task ->
+        task.group = 'jar compatibility'
+        task.onlyIf {
+            baseForgeVersionProperty.getOrNull() != null
+        }
+    }
+
+    tasks.register('setupCheckJarCompatibility', SetupCheckJarCompatibility) {
+        inputVersion = baseForgeVersionProperty
+    }
+
+    tasks.register('applyBaseCompatibilityJarBinPatches', ApplyBinPatches) {
+        jarCompatibilityTaskSetup(it)
+
+        clean = project.tasks.createJoinedSRG.output
+        patch = project.tasks.named('setupCheckJarCompatibility').flatMap { it.baseBinPatchesOutput }
+        output = project.layout.buildDirectory.dir(name).map { it.file('output.jar') }
+    }
+
+    tasks.register('mergeBaseForgeJar', MergeJars) {
+        jarCompatibilityTaskSetup(it)
+
+        inputJars.from(project.tasks.named('applyBaseCompatibilityJarBinPatches').flatMap { it.output })
+        inputJars.from(baseForgeVersionProperty.map { inputVersion ->
+            def output = project.layout.buildDirectory.dir(name).map { it.file("forge-${inputVersion}-universal.jar") }.get().asFile
+            project.rootProject.extensions.download.run {
+                src "https://maven.minecraftforge.net/net/minecraftforge/forge/${inputVersion}/forge-${inputVersion}-universal.jar"
+                dest output
+            }
+            return output
+        })
+    }
+
+    tasks.register('checkJarCompatibility', CheckJarCompatibility) {
+        jarCompatibilityTaskSetup(it)
+        dependsOn 'setupCheckJarCompatibility'
+
+        baseJar = project.tasks.named('mergeBaseForgeJar').flatMap { it.output }
+    }
+
+    task checkAll(dependsOn: [checkATs, checkSAS, checkExcs, findFieldInstanceChecks, checkPatches, checkLicenses]){}
+
     task launcherJson(type: LauncherJson) {
         packedDependencies = [':fmlloader:jar']
         doFirst {
@@ -1187,12 +1264,15 @@ project(':forge') {
                            '--fml.mcVersion', MC_VERSION,
                            '--fml.forgeGroup', project.group,
                            '--fml.mcpVersion', MCP_VERSION],
-                    jvm: ["-DignoreList=${forge_client.properties.ignoreList},\${version_name}.jar",
-                          //"-DmergeModules=${forge_client.properties.mergeModules}",
+                    jvm: ['-Djava.net.preferIPv6Addresses=system',
+                          "-DignoreList=${forge_client.properties.ignoreList},\${version_name}.jar",
+                          "-DmergeModules=${forge_client.properties.mergeModules}",
                           '-DlibraryDirectory=${library_directory}',
                           '-p', Util.getArtifacts(project, configurations.moduleonly, false).values().collect{'${library_directory}/' + it.downloads.artifact.path}.join('${classpath_separator}'),
                           '--add-modules', 'ALL-MODULE-PATH',
+                          // Additions to these JVM module args should be mirrored to server_files/args.txt and other similar blocks in the buildscript
                           '--add-opens', 'java.base/java.util.jar=cpw.mods.securejarhandler',
+                          '--add-opens', 'java.base/java.lang.invoke=cpw.mods.securejarhandler',
                           '--add-exports', 'java.base/sun.security.util=cpw.mods.securejarhandler',
                           '--add-exports', 'jdk.naming.dns/com.sun.jndi.dns=java.naming'
                     ]
@@ -1476,7 +1556,7 @@ project(':forge') {
                 MAPPING_CHANNEL: MAPPING_CHANNEL,
                 MAPPING_VERSION: MAPPING_VERSION,
                 FORGE_SPEC_VERSION: SPEC_VERSION.split("\\.")[0],
-                MC_NEXT_VERSION: "1."+((MC_VERSION.split("[\\.-]")[1] as int)+1)
+                MC_NEXT_VERSION: MC_NEXT_VERSION
             ])
             rename 'gitignore\\.txt', '.gitignore'
             rename 'gitattributes\\.txt', '.gitattributes'
@@ -1487,12 +1567,6 @@ project(':forge') {
         header = file("$rootDir/LICENSE-header.txt")
 
         include 'net/minecraftforge/'
-        exclude 'net/minecraftforge/server/terminalconsole/'
-        exclude 'net/minecraftforge/api/' // exclude API here because it's validated in the SPI build
-        exclude 'net/minecraftforge/fml/common/versioning/ComparableVersion.java'
-        exclude 'net/minecraftforge/fml/common/versioning/InvalidVersionSpecificationException.java'
-        exclude 'net/minecraftforge/fml/common/versioning/Restriction.java'
-        exclude 'net/minecraftforge/fml/common/versioning/VersionRange.java'
         exclude 'net/minecraftforge/common/LenientUnboundedMapCodec.java'
 
         tasks {
@@ -1523,6 +1597,83 @@ project(':forge') {
         sourceSets.test.java.srcDirs.each { extractMappedNew.addTarget it }
     }
 
+    tasks.named('javadoc', Javadoc).configure {
+        description 'Generates the combined javadocs for the FML projects and the main Forge project'
+        var includedProjects = [ ':fmlcore', ':fmlloader', ':javafmllanguage', ':mclanguage' ]
+        source includedProjects.collect { project(it).sourceSets.main.allJava }
+        classpath = classpath + files(includedProjects.collect { project(it).sourceSets.main.compileClasspath })
+
+        var docsDir = rootProject.file('src/docs/')
+        inputs.dir(docsDir)
+            .withPropertyName('docs resources directory')
+            .withPathSensitivity(PathSensitivity.RELATIVE)
+            .optional()
+
+        failOnError = false
+
+        // Exclude the Minecraft classes if not enabled
+        if (!project.hasProperty('generateAllDocumentation')) {
+            exclude 'net/minecraft/**'
+            exclude 'com/mojang/**'
+        }
+        exclude 'mcp/**'
+
+        options.addStringOption('Xdoclint:all,-missing', '-public')
+        options {
+            stylesheetFile = new File(docsDir, 'stylesheet.css')
+
+            tags = [
+                'apiNote:a:<em>API Note:</em>',
+                'implSpec:a:<em>Implementation Requirements:</em>',
+                'implNote:a:<em>Implementation Note:</em>'
+            ]
+
+            groups = [
+                'Forge Mod Loader': [
+                    'net.minecraftforge.fml.common.asm*',
+                    'net.minecraftforge.fml.loading*',
+                    'net.minecraftforge.fml.server*'
+                ],
+                'FML Core':  [
+                    'net.minecraftforge.fml',
+                    'net.minecraftforge.fml.config*',
+                    'net.minecraftforge.fml.event*',
+                    'net.minecraftforge.fml.util*'
+                ],
+                'FML Common': [
+                    'net.minecraftforge.fml.core',
+                    'net.minecraftforge.fml.event.config',
+                    'net.minecraftforge.fml.event.lifecycle'
+                ],
+                'FML Java/MC Language Providers': [
+                    'net.minecraftforge.fml.common',
+                    'net.minecraftforge.fml.javafmlmod',
+                    'net.minecraftforge.fml.mclanguageprovider'
+                ],
+                'Minecraft Forge API': [
+                    'net.minecraftforge*'
+                ]
+            ]
+
+            author = false
+            noSince = true
+            noHelp = true
+
+            bottom = "Minecraft Forge is an open source modding API for Minecraft: Java Edition, licensed under the Lesser GNU General Public License, version 2.1."
+            windowTitle = "Minecraft Forge API ${VERSION}"
+            docTitle = "Minecraft Forge API - ${FORGE_VERSION} for Minecraft ${MC_VERSION}"
+            header = "<div style=\"margin-top: 9px;padding: 5px 6px;\"><strong>${FORGE_VERSION} for Minecraft ${MC_VERSION}</strong></div>"
+        }
+
+        doLast {
+            project.copy {
+                from docsDir
+                exclude '/stylesheet.css'
+                into destinationDir
+            }
+        }
+    }
+
     publishing {
         publications {
             mavenJava(MavenPublication) {
@@ -1536,7 +1687,11 @@ project(':forge') {
         }
     }
     // Since we need the modules in the bootstrap, we need to make sure they are compiled before we do each run
-    afterEvaluate { prepareRuns.dependsOn(':fmlcore:jar', ':fmlloader:jar', ':javafmllanguage:jar', ':mclanguage:jar') }
+    afterEvaluate { prepareRuns.dependsOn(PACKED_DEPS) }
+
+    tasks.withType(JavaCompile).configureEach {
+        options.encoding = 'UTF-8' // Use the UTF-8 charset for Java compilation
+    }
 }
 
 //evaluationDependsOnChildren()

buildSrc/build.gradle

@@ -2,8 +2,10 @@ repositories {
     maven { url = 'https://maven.minecraftforge.net/' }
 	mavenCentral()
 }
+
 dependencies {
-	implementation 'org.ow2.asm:asm:9.1'
-	implementation 'org.ow2.asm:asm-tree:9.1'
+	implementation 'org.ow2.asm:asm:9.3'
+	implementation 'org.ow2.asm:asm-tree:9.3'
     implementation 'net.minecraftforge:srgutils:0.4.+'
+    implementation 'commons-io:commons-io:2.8.0'
 }

buildSrc/src/main/groovy/net/minecraftforge/forge/tasks/CheckSAS.groovy

@@ -28,36 +28,80 @@ abstract class CheckSAS extends DefaultTask {
 				}
 				def comment = idx == -1 ? null : line.substring(idx)
 				if (idx != -1) line = line.substring(0, idx - 1)
-				def (cls, desc) = (line.trim() + '    ').split(' ', -1)
+				def (cls, name, desc) = (line.trim().replace('(', ' (') + '     ').split(' ', -1)
 				cls = cls.replaceAll('\\.', '/')
-				desc = desc.replace('(', ' (')
 
-				if (json[cls] == null || (!desc.isEmpty() && (json[cls]['methods'] == null || json[cls]['methods'][desc] == null))) {
+				if (json[cls] == null) {
 					println('Invalid: ' + line)
-					return
-				}
-
-				//Class SAS
-				if (desc.isEmpty()) {
-					lines.add(cls + (comment == null ? '' : ' ' + comment))
-					if (json[cls]['methods'] != null)
-						(json[cls]['methods'] as TreeMap).each {
-							findChildMethods(json, cls, it.key).each { lines.add('\t' + it) }
+				} else if (name.isEmpty()) { //Class SAS
+                    def toAdd = []
+                    def clsSided = isSided(json[cls])
+                    def sided = clsSided
+                    
+                    /* TODO: MergeTool doesn't do fields
+                    if (json[cls]['fields'] != null) {
+						for (entry in json[cls]['fields']) {
+                            if (isSided(entry.value)) {
+                                sided = true
+                                toAdd.add('\t' + cls + ' ' + entry.key)
+                            }
 						}
-					return
-				}
-
-				//Method SAS
-				lines.add(cls + ' ' + desc.replace(' ', '') + (comment == null ? '' : ' ' + comment))
-				findChildMethods(json, cls, desc).each { lines.add('\t' + it) }
+                    }
+                    */
+					if (json[cls]['methods'] != null) {
+                        for (entry in json[cls]['methods']) {
+                            if (isSided(entry.value)) {
+                                sided = true
+                                toAdd.add('\t' + cls + ' ' + entry.key.replaceAll(' ', ''))
+                                findChildMethods(json, cls, entry.key).each { lines.add('\t' + it) }
+                                findChildMethods(json, cls, entry.key).each { println(line + ' -- ' + it) }
+                            } else if (clsSided) {
+                                findChildMethods(json, cls, entry.key).each { lines.add('\t' + it) }
+                                findChildMethods(json, cls, entry.key).each { println(line + ' -- ' + it) }
+                            }
+						}
+                    }
+                    
+                    if (sided) {
+                        lines.add(cls + (comment == null ? '' : ' ' + comment))
+                        lines.addAll(toAdd.sort())
+                    } else
+                        println('Invalid: ' + line)
+                    
+                } else if (desc.isEmpty()) { // Fields
+                    /* TODO: MergeTool doesn't do fields
+                    if (json[cls]['fields'] != null && isSided(json[cls]['fields'][name]))
+                        lines.add(cls + ' ' + name + (comment == null ? '' : ' ' + comment))
+                    else
+                    */
+                        println('Invalid: ' + line)
+                } else { // Methods
+                    if (json[cls]['methods'] == null || !isSided(json[cls]['methods'][name + ' ' + desc]))
+                        println('Invalid: ' + line)
+                    else {
+                        lines.add(cls + ' ' + name + desc + (comment == null ? '' : ' ' + comment))
+                        findChildMethods(json, cls, name + ' ' + desc).each { println(line + ' -- ' + it) }
+                        findChildMethods(json, cls, name + ' ' + desc).each { lines.add('\t' + it) }
+                    }
+                }
 			}
 			f.text = lines.join('\n')
 		}
 	}
 
+    protected static isSided(json) {
+        if (json == null || json['annotations'] == null)
+            return false
+        for (ann in json['annotations']) {
+            if ('Lnet/minecraftforge/api/distmarker/OnlyIn;'.equals(ann.desc))
+                return true
+        }
+        return false
+    }
+    
 	protected static findChildMethods(json, cls, desc)
 	{
-		return json.values().findAll{ it.methods != null && it.methods[desc] != null && it.methods[desc].override == cls}
+		return json.values().findAll{ it.methods != null && it.methods[desc] != null && it.methods[desc].override == cls && isSided(it.methods[desc]) }
 				.collect { it.name + ' ' + desc.replace(' ', '') } as TreeSet
 	}
 }

buildSrc/src/main/groovy/net/minecraftforge/forge/tasks/MergeJars.groovy

@@ -0,0 +1,44 @@
+package net.minecraftforge.forge.tasks
+
+import org.apache.commons.io.IOUtils
+import org.gradle.api.DefaultTask
+import org.gradle.api.file.ConfigurableFileCollection
+import org.gradle.api.file.RegularFileProperty
+import org.gradle.api.tasks.InputFiles
+import org.gradle.api.tasks.OutputFile
+import org.gradle.api.tasks.TaskAction
+
+import java.util.zip.ZipEntry
+import java.util.zip.ZipInputStream
+import java.util.zip.ZipOutputStream
+
+abstract class MergeJars extends DefaultTask {
+    MergeJars() {
+        output.convention(project.layout.buildDirectory.dir(name).map { it.file('output.jar') })
+    }
+
+    @TaskAction
+    void run() {
+        def jars = inputJars.files
+
+        try (ZipOutputStream zout = new ZipOutputStream(new FileOutputStream(output.get().asFile))) {
+            for (def jar : jars) {
+                try (ZipInputStream zin = new ZipInputStream(new FileInputStream(jar))) {
+                    def entry
+                    while ((entry = zin.getNextEntry()) != null) {
+                        ZipEntry _new = new ZipEntry(entry.getName())
+                        _new.setTime(0) //SHOULD be the same time as the main entry, but NOOOO _new.setTime(entry.getTime()) throws DateTimeException, so you get 0, screw you!
+                        zout.putNextEntry(_new)
+                        IOUtils.copy(zin, zout)
+                    }
+                }
+            }
+        }
+    }
+
+    @InputFiles
+    abstract ConfigurableFileCollection getInputJars()
+
+    @OutputFile
+    abstract RegularFileProperty getOutput()
+}

buildSrc/src/main/groovy/net/minecraftforge/forge/tasks/SetupCheckJarCompatibility.groovy

@@ -0,0 +1,64 @@
+package net.minecraftforge.forge.tasks
+
+import org.gradle.api.DefaultTask
+import org.gradle.api.artifacts.Dependency
+import org.gradle.api.file.RegularFileProperty
+import org.gradle.api.provider.Property
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.Optional
+import org.gradle.api.tasks.OutputFile
+import org.gradle.api.tasks.TaskAction
+
+import java.nio.file.Files
+import java.nio.file.StandardCopyOption
+
+abstract class SetupCheckJarCompatibility extends DefaultTask {
+    SetupCheckJarCompatibility() {
+        group = 'jar compatibility'
+        onlyIf {
+            inputVersion.getOrNull() != null
+        }
+
+        baseBinPatchesOutput.convention(project.layout.buildDirectory.dir(name).map { it.file('joined.lzma') })
+    }
+
+    @TaskAction
+    void run() {
+        def inputVersion = inputVersion.get()
+        def fmlLibs = project.configurations.detachedConfiguration(project.PACKED_DEPS.collect {
+            def artifactId = it.split(':')[1]
+            return project.dependencies.create("net.minecraftforge:${artifactId}:${inputVersion}")
+        }.toArray(Dependency[]::new))
+
+        project.tasks.named('checkJarCompatibility') {
+            baseLibraries.from(project.tasks.createJoinedSRG.output)
+            baseLibraries.from(project.provider {
+                fmlLibs.resolvedConfiguration.lenientConfiguration.files
+            })
+
+            inputJar = project.tasks.reobfJar.output
+            concreteLibraries.from(project.PACKED_DEPS.collect { project.rootProject.tasks.getByPath(it).archiveFile })
+
+            commonLibraries.from(project.configurations.minecraftImplementation)
+            commonLibraries.from(project.configurations.installer)
+            commonLibraries.from(project.configurations.moduleonly)
+        }
+
+        def baseForgeUserdev = project.layout.buildDirectory.dir(name).map { it.file("forge-${inputVersion}-userdev.jar") }.get().asFile
+        project.rootProject.extensions.download.run {
+            src "https://maven.minecraftforge.net/net/minecraftforge/forge/${inputVersion}/forge-${inputVersion}-userdev.jar"
+            dest baseForgeUserdev
+        }
+
+        def joinedLzma = project.zipTree(baseForgeUserdev).matching { it.include('joined.lzma') }.singleFile
+
+        Files.copy(joinedLzma.toPath(), baseBinPatchesOutput.get().asFile.toPath(), StandardCopyOption.REPLACE_EXISTING)
+    }
+
+    @Input
+    @Optional
+    abstract Property<String> getInputVersion()
+
+    @OutputFile
+    abstract RegularFileProperty getBaseBinPatchesOutput()
+}

buildSrc/src/main/groovy/net/minecraftforge/forge/tasks/Util.groovy

@@ -18,17 +18,17 @@ public class Util {
 			return md.digest().collect {String.format "%02x", it}.join()
 		}
         File.metaClass.getSha1 = { !delegate.exists() ? null : delegate.sha1() }
-	
+
 		File.metaClass.json = { -> new JsonSlurper().parseText(delegate.text) }
         File.metaClass.getJson = { return delegate.exists() ? new JsonSlurper().parse(delegate) : [:] }
         File.metaClass.setJson = { json -> delegate.text = new JsonBuilder(json).toPrettyString() }
-		
+
 		Date.metaClass.iso8601 = { ->
 			def format = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ")
 			def result = format.format(delegate)
 			return result[0..21] + ':' + result[22..-1]
 		}
-        
+
         String.metaClass.rsplit = { String del, int limit = -1 ->
             def lst = new ArrayList()
             def x = 0, idx
@@ -41,7 +41,7 @@ public class Util {
             return lst
         }
 	}
-	
+
 	public static String[] getClasspath(project, libs, artifact) {
 		def ret = []
 		artifactTree(project, artifact).each { key, lib ->
@@ -51,7 +51,7 @@ public class Util {
 		}
 		return ret
 	}
-	
+
 	public static def getArtifacts(project, config, classifiers) {
 		def ret = [:]
 		config.resolvedConfiguration.resolvedArtifacts.each {
@@ -75,7 +75,7 @@ public class Util {
 				url = "https://maven.minecraftforge.net/${path}"
 			}
 			//TODO remove when Mojang launcher is updated
-			if (!classifiers && art.classifier != null) { 
+			if (!classifiers && art.classifier != null) {
 				//Mojang launcher doesn't currently support classifiers, so... move it to part of the version, and force the extension to 'jar'
 				// However, keep the path normal so that our mirror system works.
 				art.version = "${art.version}-${art.classifier}"
@@ -96,14 +96,14 @@ public class Util {
 		}
 		return ret
 	}
-    
-    public static def getMavenPath(task) {        
+
+    public static def getMavenPath(task) {
         def classifier = task.archiveClassifier.get()
         def dep = "${task.project.group}:${task.project.name}:${task.project.version}" + (classifier == '' ? '' : ':' + classifier)
         return "${task.project.group.replace('.', '/')}/${task.project.name}/${task.project.version}/${task.project.name}-${task.project.version}".toString() + (classifier == '' ? '' : '-' + classifier) + '.jar'
     }
-    
-    public static def getMavenDep(task) {        
+
+    public static def getMavenDep(task) {
         def classifier = task.archiveClassifier.get()
         return "${task.project.group}:${task.project.name}:${task.project.version}" + (classifier == '' ? '' : ':' + classifier)
     }
@@ -127,7 +127,7 @@ public class Util {
 		def files = cfg.resolve()
 		return getArtifacts(project, cfg, true)
 	}
-	
+
 	private static boolean checkExists(url) {
 		try {
 			def code = new URL(url).openConnection().with {
@@ -142,4 +142,9 @@ public class Util {
 			throw e
 		}
 	}
+
+    public static String getLatestForgeVersion(mcVersion) {
+        def json = new JsonSlurper().parseText(new URL("https://files.minecraftforge.net/net/minecraftforge/forge/promotions_slim.json").getText("UTF-8"))
+        return json.promos["$mcVersion-latest"]
+    }
 }

docs/CONTRIBUTING.md

@@ -1,11 +1,11 @@
 Contributing to Forge
 =====================
 
-1) Keep patches to Minecraft classes minimal. If you need a lot of things done, you may either add to relevant forge classes or make a new class.
+1) Keep patches to Minecraft classes together. If you need a lot of things done, you may either add to relevant forge classes or make a new class. Try not to spread out your patches across multiple disjoint lines, as this makes maintenance of your patches difficult.
 
-2) An example mod must be provided for all PRs adding events/hooks to Forge. Whether it's a full mod using your proposed hooks, or just a pastebin containing a simple example, an example mod is required. Please also explain in detail what your new hook does.
+2) TODO: Test Mods
 
-3) Follow Forge coding guidelines (braces on newlines, spaces instead of tabs, etc)
+3) Follow the code style of the class you're working in (braces on newlines & spaces instead of tabs in Forge classes, inline brackets in patches, etc).
 
 For more information, refer to [the wiki](https://github.com/MinecraftForge/MinecraftForge/wiki/If-you-want-to-contribute-to-Forge)
 

docs/README.md

@@ -2,16 +2,16 @@
 
 MinecraftForge
 =============
-[![Stable Release](https://img.shields.io/badge/dynamic/json?url=https://files.minecraftforge.net/net/minecraftforge/forge/promotions_slim.json&label=Stable&prefix=1.18-&query=$.promos["1.18-recommended"]&color=brightgreen&logo=data:image/svg+xml;base64,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)](https://files.minecraftforge.net)
-[![Latest Release](https://img.shields.io/badge/dynamic/json?url=https://files.minecraftforge.net/net/minecraftforge/forge/promotions_slim.json&label=Latest&prefix=1.18-&query=$.promos["1.18-latest"]&color=blue&logo=data:image/svg+xml;base64,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
+[![Stable Release](https://img.shields.io/badge/dynamic/json?url=https://files.minecraftforge.net/net/minecraftforge/forge/promotions_slim.json&label=Stable&prefix=1.19-&query=$.promos["1.19.2-recommended"]&color=brightgreen&logo=data:image/svg+xml;base64,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)](https://files.minecraftforge.net)
+[![Latest Release](https://img.shields.io/badge/dynamic/json?url=https://files.minecraftforge.net/net/minecraftforge/forge/promotions_slim.json&label=Latest&prefix=1.19.2-&query=$.promos["1.19.2-latest"]&color=blue&logo=data:image/svg+xml;base64,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
 )](https://files.minecraftforge.net) [![Discord](https://img.shields.io/discord/313125603924639766.svg?color=%237289da&label=Discord&logo=discord&logoColor=%237289da)](https://discord.gg/UvedJ9m) [![Support](https://img.shields.io/badge/Patreon-Support-orange.svg?logo=Patreon)](https://www.patreon.com/LexManos)
 
 Forge is a free, open-source modding API all of your favourite mods use!
 
-|    Version    |    Support    |
-| ------------- | ------------- |
-|    1.18.x     |    Active     |
-|    1.16.x     |    LTS        |
+| Version |    Support    |
+|---------| ------------- |
+| 1.19.x  |    Active     |
+| 1.18.x  |    LTS        |
 
 * [Download]
 * [Forum]
@@ -29,7 +29,7 @@ You can download the installer for the *Recommended Build* or the
  into your vanilla launcher environment, where you can then create a new
  profile using that version and play the game!
  
-For support and questions, visit [the Support Forum](https://www.minecraftforge.net/forum/forum/18-support-bug-reports/).
+For support and questions, visit [the Support Forum](https://www.minecraftforge.net/forum/forum/18-support-bug-reports/) or [the Forge Discord server](https://discord.gg/forge).
 
 [Here is a short video from Rorax showing how to install and setup Forge.](https://www.youtube.com/watch?v=lB3ArN_-3Oc)
 
@@ -41,7 +41,7 @@ For support and questions, visit [the Support Forum](https://www.minecraftforge.
 
 If you wish to actually inspect Forge, submit PRs or otherwise work
  with Forge itself, you're in the right place!
- 
+
  [See the guide to setting up a Forge workspace](http://mcforge.readthedocs.io/en/latest/forgedev/).
 
 ### Pull requests
@@ -51,13 +51,14 @@ If you wish to actually inspect Forge, submit PRs or otherwise work
 Please read the contributing guidelines found [here](CONTRIBUTING.md) before making a pull request.
 
 ### Contributor License Agreement
-We require all contributors to acknowledge the [Forge Contributor
- License Agreement](https://cla-assistant.io/MinecraftForge/MinecraftForge). Please ensure you have a valid email address
- associated with your GitHub account to do this. If you have previously
+We require all contributors to acknowledge the [Forge Contributor License Agreement](https://cla-assistant.io/MinecraftForge/MinecraftForge). 
+Please ensure you have a valid email address associated with your GitHub account to do this. If you have previously 
  signed it, you should be OK.
 
 #### Donate
-*Forge is a large project with many collaborators working on it around the clock. Forge is and will always remain free to use and modify. However, it costs money to run such a large project as this, so please consider [becoming a patron](https://www.patreon.com/LexManos).*
+*Forge is a large project with many collaborators working on it around the clock. Forge is and will always remain free 
+ to use and modify. However, it costs money to run such a large project as this, so please consider 
+ [becoming a patron](https://www.patreon.com/LexManos).*
 
 [Download]: https://files.minecraftforge.net/
 [Forum]: https://www.minecraftforge.net/forum/

docs/SUPPORT.md

@@ -76,7 +76,7 @@ If you're certain you've found an issue that is directly caused by Forge, you ha
 
  1. **Forge Forums:** There's a dedicated [Support & Bug Report](http://www.minecraftforge.net/forum/forum/18-support-bug-reports/) section on the Forge forums, which is led by team of moderators and volunteers who will try to deal with your reports as quickly as possible. *As a player you should probably report here first.*
    - For modders, there also is a separate [Modder Support](http://www.minecraftforge.net/forum/forum/70-modder-support/) section where you can ask all your development-related questions. *You should prefer this section for coding help.*
- 2. **Forge IRC Channel:** You can find a lot of help on the official [`#minecraftforge`](irc://irc.esper.net:6667/minecraftforge) channel on EsperNet. Especially smaller issues that you quickly need help with could be reported there. *Be aware that the channel is more suited towards development questions, so while you may get support there as a player, you should almost always prefer the forums.*
+ 2. **Forge Discord Server:** You can find a lot of help on the official [Discord Server](https://discord.gg/forge), especially smaller issues that you quickly need help with. *Be aware that the channel is more suited towards development questions, so while you may get support there as a player, you should almost always prefer the forums.*
  3. **Forge Issue Tracker:** If you're absolutely certain that you've found an issue in the Forge codebase (e.g. you're a modder yourself and have analyzed the stacktrace and relevant code), don't refrain from reporting it on this repository's [issue tracker](https://github.com/MinecraftForge/MinecraftForge/issues). *Please do not use the issues as a means of getting coding help. For developers, the IRC and the [official documentation](https://mcforge.readthedocs.io) are the best sources of information.*
 
 ### Mod Support
@@ -84,7 +84,8 @@ If you're certain you've found an issue that is directly caused by Forge, you ha
 A lot of mods also use GitHub or other source management systems and their integrated issue trackers. The following options will give you the best chances of reporting your issue in the right place:
 
  - **CurseForge:** Many mods are hosted on the [CurseForge platform](https://minecraft.curseforge.com) nowadays. Chances are you already downloaded them from there or as a part of a modpack hosted there. Projects may specify an issue reporting link on their own page, so simply look for it on the mod's project page and you should be directed to the preferred means of error reporting.
- - **Searching for a repository directly:** You may need to try and find a repository directly on source control sites. The most common ones are [GitHub](https://github.com) and [BitBucket](https://bitbucket.org). Both come with search capabilities, so simply try to search for the mod's name.
+ - **Modrinth:** Some modders use [Modrinth](https://modrinth.com/mods) to host their mods, but be mindful that not all mods on this platform are for the Forge modloader.
+ - **Searching for a repository directly:** You may need to try and find a repository directly on source control sites. The most common ones are [GitHub](https://github.com), [GitLab](https://gitlab.com), and [BitBucket](https://bitbucket.org). Both come with search capabilities, so simply try to search for the mod's name.
 
 ### Vanilla Support
 

fmlcore/build.gradle

@@ -1,6 +1,7 @@
 plugins {
     id 'com.github.ben-manes.versions'
     id 'org.javamodularity.moduleplugin' version '1.8.3' apply false
+    id 'org.cadixdev.licenser'
 }
 apply plugin: 'java-library'
 apply plugin: 'jacoco'
@@ -9,10 +10,12 @@ apply plugin: 'org.javamodularity.moduleplugin'
 dependencyUpdates.rejectVersionIf { isNonStable(it.candidate.version) }
 
 dependencies {
-    compileOnly('org.jetbrains:annotations:21.0.1')
+    compileOnly("org.jetbrains:annotations:${JETBRAINS_ANNOTATIONS_VERSION}")
+
+    api("net.minecraftforge:eventbus:${EVENTBUS_VERSION}")
+
     implementation(project(':fmlloader'))
-    api('net.minecraftforge:eventbus:5.0.+')
-    implementation('commons-io:commons-io:2.5')
+    implementation("commons-io:commons-io:${COMMONS_IO_VERSION}")
 }
 
 task sourcesJar(type: Jar) {
@@ -53,6 +56,12 @@ tasks.withType(JavaCompile) {
     options.compilerArgs << '-Xlint:unchecked'
 }
 
+license {
+    header = rootProject.file('LICENSE-header.txt')
+
+    include 'net/minecraftforge/'
+}
+
 artifacts {
     archives jar
     archives sourcesJar

fmlcore/src/main/java/net/minecraftforge/fml/Bindings.java

@@ -1,3 +1,8 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.fml;
 
 import cpw.mods.modlauncher.util.ServiceLoaderUtils;

fmlcore/src/main/java/net/minecraftforge/fml/CrashReportCallables.java

@@ -1,3 +1,8 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.fml;
 
 import java.util.ArrayList;

fmlcore/src/main/java/net/minecraftforge/fml/DeferredWorkQueue.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;

fmlcore/src/main/java/net/minecraftforge/fml/DistExecutor.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;

fmlcore/src/main/java/net/minecraftforge/fml/I18NParser.java

@@ -1,3 +1,8 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.fml;
 
 public interface I18NParser {

fmlcore/src/main/java/net/minecraftforge/fml/IBindingsProvider.java

@@ -1,3 +1,8 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.fml;
 
 import net.minecraftforge.eventbus.api.IEventBus;

fmlcore/src/main/java/net/minecraftforge/fml/ICrashCallable.java

@@ -0,0 +1,5 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+

fmlcore/src/main/java/net/minecraftforge/fml/IExtensionPoint.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;
@@ -22,41 +8,92 @@ package net.minecraftforge.fml;
 import java.util.function.BiPredicate;
 import java.util.function.Supplier;
 
+/**
+ * An extension point for a mod container.
+ *
+ * <p>An extension point can be registered for a mod container using {@link ModContainer#registerExtensionPoint(Class, Supplier)}
+ * and retrieved (if present) using {@link ModContainer#getCustomExtension(Class)}. An extension point allows a mod to
+ * supply an arbitrary value as a record class to another mod or framework through their mod container class, avoiding
+ * the use of {@link InterModComms} or other external frameworks to pass around these values.</p>
+ *
+ * <p>The usual way to declare an extension point is to implement this interface on a record class, with the type
+ * parameter being a reference to the class itself. For example, {@code record MyExtension(...) extends
+ * IExtensionPoint<MyExtension>} would declare an extension point which supplies a {@code MyExtension} object. However,
+ * there is no hard requirement that an extension point's type parameter must be in reference to itself; the type
+ * parameter may reference another record class instead.</p>
+ *
+ * @param <T> the type of the record which is held by the extension point
+ */
+@SuppressWarnings("unused") // Type parameter T
 public interface IExtensionPoint<T extends Record>
 {
     /**
-     * Compatibility display test for the mod.
-     * Used for displaying compatibility with remote servers with the same mod, and on disk saves.
+     * Extension point for the compatibility display test used on the server selection screen.
      *
-     * The supplier provides my "local" version for sending across the impl or writing to disk
-     * The predicate tests the version from a remote instance or save for acceptability (Boolean is true for impl, false for local save)
-     * and returns true if the version is compatible.
+     * <em>Note: "server" and "client" refers to the {@linkplain net.minecraftforge.api.distmarker.Dist#DEDICATED_SERVER dedicated server}
+     * and {@linkplain net.minecraftforge.api.distmarker.Dist#CLIENT game client} physical distributions, rather than the
+     * {@linkplain LogicalSide logical server and client}.</em>
      *
-     * <p>Return {@code net.minecraftforge.impl.impl.FMLNetworkConstants#IGNORESERVERONLY} in the supplier, if you wish to be ignored
-     * as a server side only mod.</p>
-     * <p>Return true in the predicate for all values of the input string (when impl boolean is true) if you are client side,
-     * and don't care about matching any potential server version.</p>
+     * <p>The {@link Supplier} provides the local compatibility version, which is sent from the server to the client
+     * for multiplayer connections or stored to disk for the world save. The {@link BiPredicate} accepts the remote
+     * compatibility version and a boolean indicating whether the remote version is from the server or a world save,
+     * where {@code true} means it is from the server and {@code false} means it is from the world save. The return
+     * value of the predicate determines whether the remote version is "compatible" for the purposes of the display test.</p>
      *
-     * <p>
-     * Examples: A server only mod
-     * </p>
+     * <p>The local compatibility version may be of the value {@link net.minecraftforge.network.NetworkConstants#IGNORESERVERONLY},
+     * in which case clients will ignore the mod's presence if it is present on the server but not on the client.
+     * However, the remote version test predicate must still accept this value as a remote version in order to display
+     * as compatible if the mod is present on the client.</p>
+     *
+     * <p><strong>The compatibility display test does not necessarily indicate the success or failure of an actual
+     * connection attempt.</strong> Factors such as display test extension misconfiguration, truncation of ping data,
+     * difference of registry data or network channels between server and client, and others may cause the result of the
+     * compatibility test to not reflect the actual likelihood of a connection successfully being established between
+     * the server and the client.</p>
+     *
+     * <p>An example declaration of a display test extension registration for a regular mod (requires to be present on
+     * server and client) is as follows:</p>
      * <pre>{@code
-     *     registerExtensionPoint(DISPLAYTEST, ()->Pair.of(
-     *      ()->FMLNetworkConstants.IGNORESERVERONLY, // ignore me, I'm a server only mod
-     *      (s,b)->true // i accept anything from the server or the save, if I'm asked
-     *     )
+     * String compatibilityVersion = "1"; // Could be linked with a network channel version or mod version
+     * ModLoadingContext.get().registerExtensionPoint(IExtensionPoint.DisplayTest.class,
+     *         () -> new IExtensionPoint.DisplayTest(
+     *                 () -> compatibilityVersion,
+     *                 (remoteVersion, isFromServer) -> remoteVersion.equals(compatibilityVersion)
+     *         )
+     * );
      * }</pre>
      *
-     * <p>
-     * Examples: A client only mod
-     * </p>
+     * <p>An example declaration of a display test extension registration for a <em>server-side-only</em> mod (does not
+     * require to be present on the client) is as follows:</p>
      * <pre>{@code
-     *     registerExtensionPoint(DISPLAYTEST, ()->Pair.of(
-     *      ()->"anything. i don't care", // if i'm actually on the server, this string is sent but i'm a client only mod, so it won't be
-     *      (remoteversionstring,networkbool)->networkbool // i accept anything from the server, by returning true if it's asking about the server
-     *     )
+     * ModLoadingContext.get().registerExtensionPoint(IExtensionPoint.DisplayTest.class,
+     *         () -> new IExtensionPoint.DisplayTest(
+     *                 // Ignore this mod if not present on the client
+     *                 () -> NetworkConstants.IGNORESERVERONLY,
+     *                 // If present on the client, accept any version if from a server
+     *                 (remoteVersion, isFromServer) -> isFromServer
+     *         )
+     * );
      * }</pre>
      *
+     * <p>An example declaration of a display test extension registration for a <em>client-side-only</em> mod (does not
+     * require to be present on the server) is as follows:</p>
+     * <pre>{@code
+     * ModLoadingContext.get().registerExtensionPoint(IExtensionPoint.DisplayTest.class,
+     *         () -> new IExtensionPoint.DisplayTest(
+     *                 // Send any version from server to client, since we will be accepting any version as well
+     *                 () -> "dQw4w9WgXcQ",
+     *                 // Accept any version on the client, from server or from save
+     *                 (remoteVersion, isFromServer) -> true
+     *         )
+     * );
+     * }</pre>
+     *
+     * @see net.minecraftforge.network.ServerStatusPing
+     * @see net.minecraftforge.client.ForgeHooksClient#processForgeListPingData(net.minecraft.network.protocol.status.ServerStatus, net.minecraft.client.multiplayer.ServerData)
      */
-    record DisplayTest(Supplier<String> suppliedVersion, BiPredicate<String, Boolean> remoteVersionTest) implements IExtensionPoint<DisplayTest> {}
+    @SuppressWarnings("JavadocReference") // reference to NetworkConstants, ForgeHooksClient
+    record DisplayTest(Supplier<String> suppliedVersion, BiPredicate<String, Boolean> remoteVersionTest) implements IExtensionPoint<DisplayTest> {
+        public static final String IGNORESERVERONLY = "OHNOES\uD83D\uDE31\uD83D\uDE31\uD83D\uDE31\uD83D\uDE31\uD83D\uDE31\uD83D\uDE31\uD83D\uDE31\uD83D\uDE31\uD83D\uDE31\uD83D\uDE31\uD83D\uDE31\uD83D\uDE31\uD83D\uDE31\uD83D\uDE31\uD83D\uDE31\uD83D\uDE31\uD83D\uDE31";
+    }
 }

fmlcore/src/main/java/net/minecraftforge/fml/IModLoadingState.java

@@ -1,25 +1,86 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.fml;
 
 import net.minecraftforge.eventbus.api.Event;
 import net.minecraftforge.fml.event.IModBusEvent;
 
-import java.util.List;
 import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.Executor;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
+/**
+ * A mod loading state. During mod loading, the mod loader transitions between states in a defined sorted list of states,
+ * grouped into various {@link ModLoadingPhase phases}.
+ *
+ * @see IModStateProvider
+ */
 public interface IModLoadingState {
+    /**
+     * {@return the name of this state}
+     */
     String name();
+
+    /**
+     * {@return the name of the state immediately previous to this state} This may be a blank name, which indicates this
+     * is either the first mod loading state or an exceptional mod loading state (such as a situation where errors
+     * prevent the loading process from continuing normally).
+     */
     String previous();
+
+    /**
+     * {@return the mod loading phase this state belongs to} For exceptional mod loading states, this should be
+     * {@link ModLoadingPhase#ERROR}.
+     */
     ModLoadingPhase phase();
+
+    /**
+     * {@return a function returning a human-friendly message for this state}
+     */
     Function<ModList, String> message();
+
+    /**
+     * {@return an optional runnable, which runs before starting the transition from this state to the next}
+     * @see #buildTransition(Executor, Executor, Function, Function)
+     */
     Optional<Consumer<ModList>> inlineRunnable();
 
-    default <T extends Event & IModBusEvent> Optional<CompletableFuture<List<Throwable>>> buildTransition(final Executor syncExecutor, final Executor parallelExecutor) {
-        return buildTransition(syncExecutor, parallelExecutor, e->CompletableFuture.runAsync(()->{}, e), e->CompletableFuture.runAsync(()->{}, e));
+    /**
+     * Builds the transition task for this state with a blank pre-sync and post-sync task.
+     *
+     * @param syncExecutor a synchronous executor
+     * @param parallelExecutor a parallel executor
+     * @param <T> a type of event fired on the mod-specific event bus
+     * @return a transition task for this state
+     * @see #buildTransition(Executor, Executor, Function, Function)
+     */
+    default <T extends Event & IModBusEvent>
+    Optional<CompletableFuture<Void>> buildTransition(final Executor syncExecutor,
+                                                      final Executor parallelExecutor) {
+        return buildTransition(syncExecutor, parallelExecutor,
+                e -> CompletableFuture.runAsync(() -> {}, e),
+                e -> CompletableFuture.runAsync(() -> {}, e));
     }
 
-    <T extends Event & IModBusEvent> Optional<CompletableFuture<List<Throwable>>> buildTransition(Executor syncExecutor, Executor parallelExecutor, Function<Executor, CompletableFuture<Void>> preSyncTask, Function<Executor, CompletableFuture<Void>> postSyncTask);
+    /**
+     * Builds the transition task for this state. The pre-sync and post-sync task functions allow the transition builder
+     * to run these tasks on the same executor as the actual event dispatch and pre/post hooks.
+     *
+     * @param syncExecutor a synchronous executor
+     * @param parallelExecutor a parallel executor
+     * @param preSyncTask a function which returns a task to run before event pre-dispatch hook
+     * @param postSyncTask a function which returns a task to run after event post-dispatch hook
+     * @param <T> a type of event fired on the mod-specific event bus
+     * @return a transition task for this state
+     */
+    <T extends Event & IModBusEvent>
+    Optional<CompletableFuture<Void>> buildTransition(final Executor syncExecutor,
+                                                      final Executor parallelExecutor,
+                                                      final Function<Executor, CompletableFuture<Void>> preSyncTask,
+                                                      final Function<Executor, CompletableFuture<Void>> postSyncTask);
 }

fmlcore/src/main/java/net/minecraftforge/fml/IModStateProvider.java

@@ -1,7 +1,21 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.fml;
 
 import java.util.List;
 
+/**
+ * Provides a list of mod loading states which the mod loader may transition between.
+ *
+ * <p>There may be multiple mod state providers in a single application, where all states from each provider is
+ * combined into a single list and ordered.</p>
+ */
 public interface IModStateProvider {
+    /**
+     * {@return the list of mod loading states known to this provider}
+     */
     List<IModLoadingState> getAllStates();
 }

fmlcore/src/main/java/net/minecraftforge/fml/IModStateTransition.java

@@ -1,10 +1,14 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.fml;
 
 import net.minecraftforge.eventbus.api.Event;
 import net.minecraftforge.fml.event.IModBusEvent;
 
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.Executor;
@@ -19,18 +23,26 @@ public interface IModStateTransition {
         return new NoopTransition();
     }
 
-    default <T extends Event & IModBusEvent> CompletableFuture<List<Throwable>> build(Executor syncExecutor, Executor parallelExecutor, Function<Executor, CompletableFuture<Void>> preSyncTask, Function<Executor, CompletableFuture<Void>> postSyncTask) {
-        List<CompletableFuture<List<Throwable>>> cfs = new ArrayList<>();
+    default <T extends Event & IModBusEvent>
+    CompletableFuture<Void> build(final Executor syncExecutor,
+                                  final Executor parallelExecutor,
+                                  final Function<Executor, CompletableFuture<Void>> preSyncTask,
+                                  final Function<Executor, CompletableFuture<Void>> postSyncTask) {
+        List<CompletableFuture<Void>> futures = new ArrayList<>();
+
         this.eventFunctionStream().get()
-                .map(f->(EventGenerator<T>)f)
-                .reduce((head, tail)-> addCompletableFutureTaskForModDispatch(syncExecutor, parallelExecutor, cfs, head, ModLoadingStage::currentState, tail))
-                .ifPresent(last-> addCompletableFutureTaskForModDispatch(syncExecutor, parallelExecutor, cfs, last, nextModLoadingStage(), null));
+                .map(f -> (EventGenerator<T>) f)
+                .reduce((head, tail) -> addCompletableFutureTaskForModDispatch(syncExecutor, parallelExecutor, futures, head, ModLoadingStage::currentState, tail))
+                .ifPresent(last -> addCompletableFutureTaskForModDispatch(syncExecutor, parallelExecutor, futures, last, nextModLoadingStage(), null));
+
         final CompletableFuture<Void> preSyncTaskCF = preSyncTask.apply(syncExecutor);
-        final CompletableFuture<List<Throwable>> eventDispatchCF = ModList.gather(cfs).thenCompose(ModList::completableFutureFromExceptionList);
-        final CompletableFuture<List<Throwable>> postEventDispatchCF = preSyncTaskCF.thenComposeAsync(n -> eventDispatchCF, parallelExecutor).thenApply(r -> {
-            postSyncTask.apply(syncExecutor);
-            return r;
-        });
+        final CompletableFuture<Void> eventDispatchCF = ModList.gather(futures).thenCompose(ModList::completableFutureFromExceptionList);
+        final CompletableFuture<Void> postEventDispatchCF = preSyncTaskCF
+                .thenComposeAsync(n -> eventDispatchCF, parallelExecutor)
+                .thenApply(r -> {
+                    postSyncTask.apply(syncExecutor);
+                    return null;
+                });
         return this.finalActivityGenerator().apply(syncExecutor, postEventDispatchCF);
     }
 
@@ -38,18 +50,31 @@ public interface IModStateTransition {
         return ModLoadingStage::nextState;
     }
 
-    private <T extends Event & IModBusEvent> EventGenerator<T> addCompletableFutureTaskForModDispatch(final Executor syncExecutor, final Executor parallelExecutor, final List<CompletableFuture<List<Throwable>>> completeableFutures, final EventGenerator<T> eventGenerator, BiFunction<ModLoadingStage, Throwable, ModLoadingStage> nextState, final EventGenerator<T> nextGenerator) {
-        completeableFutures.add(((BiFunction<Executor, EventGenerator<T>, CompletableFuture<List<Throwable>>>)preDispatchHook()).apply(threadSelector().apply(syncExecutor, parallelExecutor), eventGenerator));
-        completeableFutures.add(ModList.get().futureVisitor(eventGenerator, nextState).apply(threadSelector().apply(syncExecutor, parallelExecutor)));
-        completeableFutures.add(((BiFunction<Executor, EventGenerator<T>, CompletableFuture<List<Throwable>>>)postDispatchHook()).apply(threadSelector().apply(syncExecutor, parallelExecutor), eventGenerator));
+    private <T extends Event & IModBusEvent>
+    EventGenerator<T> addCompletableFutureTaskForModDispatch(final Executor syncExecutor,
+                                                             final Executor parallelExecutor,
+                                                             final List<CompletableFuture<Void>> completableFutures,
+                                                             final EventGenerator<T> eventGenerator,
+                                                             final BiFunction<ModLoadingStage, Throwable, ModLoadingStage> nextState,
+                                                             final EventGenerator<T> nextGenerator) {
+        final Executor selectedExecutor = threadSelector().apply(syncExecutor, parallelExecutor);
+
+        var preDispatchHook = (BiFunction<Executor, EventGenerator<T>, CompletableFuture<Void>>) preDispatchHook();
+        completableFutures.add(preDispatchHook.apply(selectedExecutor, eventGenerator));
+
+        completableFutures.add(ModList.get().futureVisitor(eventGenerator, nextState).apply(threadSelector().apply(syncExecutor, parallelExecutor)));
+
+        var postDispatchHook = (BiFunction<Executor, EventGenerator<T>, CompletableFuture<Void>>) postDispatchHook();
+        completableFutures.add(postDispatchHook.apply(selectedExecutor, eventGenerator));
+
         return nextGenerator;
     }
 
     Supplier<Stream<EventGenerator<?>>> eventFunctionStream();
     ThreadSelector threadSelector();
-    BiFunction<Executor, CompletableFuture<List<Throwable>>, CompletableFuture<List<Throwable>>> finalActivityGenerator();
-    BiFunction<Executor, ? extends EventGenerator<?>, CompletableFuture<List<Throwable>>> preDispatchHook();
-    BiFunction<Executor, ? extends EventGenerator<?>, CompletableFuture<List<Throwable>>> postDispatchHook();
+    BiFunction<Executor, CompletableFuture<Void>, CompletableFuture<Void>> finalActivityGenerator();
+    BiFunction<Executor, ? extends EventGenerator<?>, CompletableFuture<Void>> preDispatchHook();
+    BiFunction<Executor, ? extends EventGenerator<?>, CompletableFuture<Void>> postDispatchHook();
 
     interface EventGenerator<T extends Event & IModBusEvent> extends Function<ModContainer, T> {
         static <FN extends Event & IModBusEvent> EventGenerator<FN> fromFunction(Function<ModContainer, FN> fn) {
@@ -71,17 +96,17 @@ record NoopTransition() implements IModStateTransition {
     }
 
     @Override
-    public BiFunction<Executor, CompletableFuture<List<Throwable>>, CompletableFuture<List<Throwable>>> finalActivityGenerator() {
+    public BiFunction<Executor, CompletableFuture<Void>, CompletableFuture<Void>> finalActivityGenerator() {
         return (e, t) -> t.thenApplyAsync(Function.identity(), e);
     }
 
     @Override
-    public BiFunction<Executor, ? extends EventGenerator<?>, CompletableFuture<List<Throwable>>> preDispatchHook() {
-        return (t, f)-> CompletableFuture.completedFuture(Collections.emptyList());
+    public BiFunction<Executor, ? extends EventGenerator<?>, CompletableFuture<Void>> preDispatchHook() {
+        return (t, f)-> CompletableFuture.completedFuture(null);
     }
 
     @Override
-    public BiFunction<Executor, ? extends EventGenerator<?>, CompletableFuture<List<Throwable>>> postDispatchHook() {
-        return (t, f)-> CompletableFuture.completedFuture(Collections.emptyList());
+    public BiFunction<Executor, ? extends EventGenerator<?>, CompletableFuture<Void>> postDispatchHook() {
+        return (t, f)-> CompletableFuture.completedFuture(null);
     }
 }

fmlcore/src/main/java/net/minecraftforge/fml/ISystemReportExtender.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;

fmlcore/src/main/java/net/minecraftforge/fml/InterModComms.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;

fmlcore/src/main/java/net/minecraftforge/fml/LoadingFailedException.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;

fmlcore/src/main/java/net/minecraftforge/fml/Logging.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;

fmlcore/src/main/java/net/minecraftforge/fml/LogicalSide.java

@@ -1,30 +1,45 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;
 
+import net.minecraftforge.api.distmarker.Dist;
+
+/**
+ * A logical side of the Minecraft game.
+ * <p>
+ * The {@linkplain Dist#CLIENT client distribution} has a copy of the logical client and the logical server, while the
+ * {@linkplain Dist#DEDICATED_SERVER dedicated server distribution} only holds
+ * the logical server.
+ *
+ * @see Dist
+ */
 public enum LogicalSide
 {
-    CLIENT, SERVER;
+    /**
+     * The logical client of the Minecraft game, which interfaces with the player's inputs and renders the player's
+     * viewpoint.
+     * <p>
+     * The logical client is only shipped with the client distribution of the game.
+     *
+     * @see Dist#CLIENT
+     */
+    CLIENT,
+    /**
+     * The logical server of the Minecraft game, responsible for connecting to clients and running the simulation logic
+     * on the level.
+     * <p>
+     * The logical server is shipped with both client and dedicated server distributions. The client distribution runs
+     * the logical server for singleplayer mode and LAN play.
+     *
+     * @see Dist#DEDICATED_SERVER
+     */
+    SERVER;
 
     /**
-     * @return if the logical side is a server.
+     * {@return if this logical side is the server}
      */
     public boolean isServer()
     {
@@ -32,7 +47,7 @@ public enum LogicalSide
     }
 
     /**
-     * @return if the logical side is a client.
+     * {@return if the logical side is the client}
      */
     public boolean isClient()
     {

fmlcore/src/main/java/net/minecraftforge/fml/ModContainer.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;
@@ -70,9 +56,24 @@ public abstract class ModContainer
         this.namespace = this.modId;
         this.modInfo = info;
         this.modLoadingStage = ModLoadingStage.CONSTRUCT;
-        // default displaytest extension checks for version string match
-        registerExtensionPoint(IExtensionPoint.DisplayTest.class, () -> new IExtensionPoint.DisplayTest(()->this.modInfo.getVersion().toString(),
-                (incoming, isNetwork)->Objects.equals(incoming, this.modInfo.getVersion().toString())));
+
+        final String displayTestString = info.getConfig().<String>getConfigElement("displayTest").orElse("MATCH_VERSION"); // missing defaults to DEFAULT type
+        Supplier<IExtensionPoint.DisplayTest> displayTestSupplier = switch (displayTestString) {
+            case "MATCH_VERSION" -> // default displaytest checks for version string match
+                    () -> new IExtensionPoint.DisplayTest(() -> this.modInfo.getVersion().toString(),
+                        (incoming, isNetwork) -> Objects.equals(incoming, this.modInfo.getVersion().toString()));
+            case "IGNORE_SERVER_VERSION" -> // Ignores any version information coming from the server - use for server only mods
+                    () -> new IExtensionPoint.DisplayTest(() -> IExtensionPoint.DisplayTest.IGNORESERVERONLY, (incoming, isNetwork) -> true);
+            case "IGNORE_ALL_VERSION" -> // Ignores all information and provides no information
+                    () -> new IExtensionPoint.DisplayTest(() -> "", (incoming, isNetwork) -> true);
+            case "NONE" -> null; // NO display test at all - use this if you're going to do your own display test
+            default -> // any other value throws an exception
+                    throw new IllegalArgumentException("Invalid displayTest value supplied in mods.toml");
+        };
+        if (displayTestSupplier != null)
+            registerExtensionPoint(IExtensionPoint.DisplayTest.class, displayTestSupplier);
+        else
+            extensionPoints.remove(IExtensionPoint.DisplayTest.class);
     }
 
     /**

fmlcore/src/main/java/net/minecraftforge/fml/ModList.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2022.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;
@@ -35,7 +21,7 @@ import java.util.AbstractMap;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.Collections;
+import java.util.Comparator;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
@@ -68,6 +54,7 @@ public class ModList
     private List<ModContainer> mods;
     private Map<String, ModContainer> indexedMods;
     private List<ModFileScanData> modFileScanData;
+    private List<ModContainer> sortedContainers;
 
     private ModList(final List<ModFile> modFiles, final List<ModInfo> sortedList)
     {
@@ -125,7 +112,7 @@ public class ModList
         return this.fileById.get(modid);
     }
 
-    <T extends Event & IModBusEvent> Function<Executor, CompletableFuture<List<Throwable>>> futureVisitor(
+    <T extends Event & IModBusEvent> Function<Executor, CompletableFuture<Void>> futureVisitor(
             final IModStateTransition.EventGenerator<T> eventGenerator,
             final BiFunction<ModLoadingStage, Throwable, ModLoadingStage> stateChange) {
         return executor -> gather(
@@ -134,12 +121,12 @@ public class ModList
                 .collect(Collectors.toList()))
             .thenComposeAsync(ModList::completableFutureFromExceptionList, executor);
     }
-    static CompletionStage<List<Throwable>> completableFutureFromExceptionList(List<? extends Map.Entry<?, Throwable>> t) {
+    static CompletionStage<Void> completableFutureFromExceptionList(List<? extends Map.Entry<?, Throwable>> t) {
         if (t.stream().noneMatch(e->e.getValue()!=null)) {
-            return CompletableFuture.completedFuture(Collections.emptyList());
+            return CompletableFuture.completedFuture(null);
         } else {
             final List<Throwable> throwables = t.stream().filter(e -> e.getValue() != null).map(Map.Entry::getValue).collect(Collectors.toList());
-            CompletableFuture<List<Throwable>> cf = new CompletableFuture<>();
+            CompletableFuture<Void> cf = new CompletableFuture<>();
             final RuntimeException accumulator = new RuntimeException();
             cf.completeExceptionally(accumulator);
             throwables.forEach(exception -> {
@@ -170,6 +157,7 @@ public class ModList
     void setLoadedMods(final List<ModContainer> modContainers)
     {
         this.mods = modContainers;
+        this.sortedContainers = modContainers.stream().sorted(Comparator.comparingInt(c->sortedList.indexOf(c.getModInfo()))).toList();
         this.indexedMods = modContainers.stream().collect(Collectors.toMap(ModContainer::getModId, Function.identity()));
     }
 
@@ -233,6 +221,10 @@ public class ModList
         indexedMods.forEach(modContainerConsumer);
     }
 
+    public void forEachModInOrder(Consumer<ModContainer> containerConsumer) {
+        this.sortedContainers.forEach(containerConsumer);
+    }
+
     public <T> Stream<T> applyForEachModContainer(Function<ModContainer, T> function) {
         return indexedMods.values().stream().map(function);
     }

fmlcore/src/main/java/net/minecraftforge/fml/ModLoader.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;
@@ -22,26 +8,25 @@ package net.minecraftforge.fml;
 import com.google.common.collect.ImmutableList;
 import net.minecraftforge.eventbus.api.Event;
 import net.minecraftforge.fml.event.IModBusEvent;
+import net.minecraftforge.fml.loading.FMLEnvironment;
 import net.minecraftforge.fml.loading.FMLLoader;
 import net.minecraftforge.fml.loading.LoadingModList;
 import net.minecraftforge.fml.loading.moddiscovery.InvalidModIdentifier;
-import net.minecraftforge.fml.loading.moddiscovery.ModFile;
 import net.minecraftforge.fml.loading.moddiscovery.ModFileInfo;
+import net.minecraftforge.fml.loading.moddiscovery.ModInfo;
 import net.minecraftforge.fml.loading.progress.StartupMessageManager;
 import net.minecraftforge.forgespi.language.IModInfo;
 import net.minecraftforge.forgespi.language.IModLanguageProvider;
+import net.minecraftforge.forgespi.locating.ForgeFeature;
+import net.minecraftforge.forgespi.locating.IModFile;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
-import java.util.Map;
-import java.util.Objects;
-import java.util.Optional;
+import java.util.*;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionException;
 import java.util.concurrent.Executor;
+import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.stream.Collectors;
@@ -110,7 +95,7 @@ public class ModLoader
                 .map(file -> new ModLoadingWarning(null, ModLoadingStage.VALIDATE, InvalidModIdentifier.identifyJarProblem(file.getFilePath()).orElse("fml.modloading.brokenfile"), file.getFileName()))
                 .collect(Collectors.toList());
         FMLLoader.getLoadingModList().getModFiles().stream()
-                .filter(ModFileInfo::missingLicense) //Search for files with missing licenses
+                .filter(ModFileInfo::missingLicense)
                 .filter(modFileInfo -> modFileInfo.getMods().stream().noneMatch(thisModInfo -> this.loadingExceptions.stream().map(ModLoadingException::getModInfo).anyMatch(otherInfo -> otherInfo == thisModInfo))) //Ignore files where any other mod already encountered an error
                 .map(modFileInfo -> new ModLoadingException(null, ModLoadingStage.VALIDATE, "fml.modloading.missinglicense", null, modFileInfo.getFile()))
                 .forEach(this.loadingExceptions::add);
@@ -147,6 +132,7 @@ public class ModLoader
      * @param periodicTask Optional periodic task to perform on the main thread while other activities run
      */
     public void gatherAndInitializeMods(final ModWorkManager.DrivenExecutor syncExecutor, final Executor parallelExecutor, final Runnable periodicTask) {
+        ForgeFeature.registerFeature("java_version", ForgeFeature.VersionFeatureTest.forVersionString(IModInfo.DependencySide.SERVER, System.getProperty("java.version")));
         loadingStateValid = true;
         statusConsumer.ifPresent(c->c.accept("Waiting for scan to complete"));
         FMLLoader.backgroundScanHandler.waitForScanToComplete(periodicTask);
@@ -159,6 +145,22 @@ public class ModLoader
             loadingStateValid = false;
             throw new LoadingFailedException(loadingExceptions);
         }
+        statusConsumer.ifPresent(c->c.accept("Validating features"));
+        List<? extends ForgeFeature.Bound> failedBounds = loadingModList.getMods().stream()
+                .map(ModInfo::getForgeFeatures)
+                .flatMap(Collection::stream)
+                .filter(bound -> !ForgeFeature.testFeature(FMLEnvironment.dist, bound))
+                .toList();
+
+        if (!failedBounds.isEmpty()) {
+            LOGGER.fatal(CORE, "Failed to validate feature bounds for mods");
+            modList.setLoadedMods(Collections.emptyList());
+            loadingStateValid = false;
+            throw new LoadingFailedException(failedBounds.stream()
+                    .map(fb -> new ModLoadingException(fb.modInfo(), ModLoadingStage.CONSTRUCT, "fml.modloading.feature.missing", null, fb.featureName(), fb.featureBound(), ForgeFeature.featureValue(fb)))
+                    .toList());
+        }
+
         statusConsumer.ifPresent(c->c.accept("Building Mod List"));
         final List<ModContainer> modContainers = loadingModList.getModFiles().stream()
                 .map(ModFileInfo::getFile)
@@ -210,7 +212,7 @@ public class ModLoader
         state.buildTransition(syncExecutor, parallelExecutor, preSyncTask, postSyncTask).ifPresent(t->waitForTransition(state, syncExecutor, ticker, t));
     }
 
-    private void waitForTransition(final IModLoadingState state, final ModWorkManager.DrivenExecutor syncExecutor, final Runnable ticker, final CompletableFuture<List<Throwable>> transition) {
+    private void waitForTransition(final IModLoadingState state, final ModWorkManager.DrivenExecutor syncExecutor, final Runnable ticker, final CompletableFuture<Void> transition) {
         while (!transition.isDone()) {
             syncExecutor.drive(ticker);
         }
@@ -236,7 +238,7 @@ public class ModLoader
         }
     }
 
-    private List<ModContainer> buildMods(final ModFile modFile)
+    private List<ModContainer> buildMods(final IModFile modFile)
     {
         final Map<String, IModInfo> modInfoMap = modFile.getModFileInfo().getMods().stream().collect(Collectors.toMap(IModInfo::getModId, Function.identity()));
 
@@ -248,17 +250,29 @@ public class ModLoader
                 .filter(Objects::nonNull)
                 .collect(Collectors.toList());
         if (containers.size() != modInfoMap.size()) {
+            var modIds = modInfoMap.values().stream().map(IModInfo::getModId).sorted().collect(Collectors.toList());
+            var containerIds = containers.stream().map(c -> c != null ? c.getModId() : "(null)").sorted().collect(Collectors.toList());
+
             LOGGER.fatal(LOADING,"File {} constructed {} mods: {}, but had {} mods specified: {}",
                     modFile.getFilePath(),
-                    containers.size(), containers.stream().map(c -> c != null ? c.getModId() : "(null)").sorted().collect(Collectors.toList()),
-                    modInfoMap.size(), modInfoMap.values().stream().map(IModInfo::getModId).sorted().collect(Collectors.toList()));
+                    containers.size(), containerIds,
+                    modInfoMap.size(), modIds);
+
+            var missingClasses = new ArrayList<>(modIds);
+            missingClasses.removeAll(containerIds);
+            LOGGER.fatal(LOADING, "The following classes are missing, but are reported in the mods.toml: {}", missingClasses);
+
+            var missingMods = new ArrayList<>(containerIds);
+            missingMods.removeAll(modIds);
+            LOGGER.fatal(LOADING, "The following mods are missing, but have classes in the jar: {}", missingMods);
+
             loadingExceptions.add(new ModLoadingException(null, ModLoadingStage.CONSTRUCT, "fml.modloading.missingclasses", null, modFile.getFilePath()));
         }
         // remove errored mod containers
         return containers.stream().filter(mc -> mc.modLoadingStage != ModLoadingStage.ERROR).collect(Collectors.toList());
     }
 
-    private ModContainer buildModContainerFromTOML(final ModFile modFile, final Map<String, IModInfo> modInfoMap, final Map.Entry<String, ? extends IModLanguageProvider.IModLanguageLoader> idToProviderEntry) {
+    private ModContainer buildModContainerFromTOML(final IModFile modFile, final Map<String, IModInfo> modInfoMap, final Map.Entry<String, ? extends IModLanguageProvider.IModLanguageLoader> idToProviderEntry) {
         try {
             final String modId = idToProviderEntry.getKey();
             final IModLanguageProvider.IModLanguageLoader languageLoader = idToProviderEntry.getValue();
@@ -287,7 +301,7 @@ public class ModLoader
             LOGGER.error("Cowardly refusing to send event generator to a broken mod state");
             return;
         }
-        ModList.get().forEachModContainer((id, mc) -> mc.acceptEvent(generator.apply(mc)));
+        ModList.get().forEachModInOrder(mc -> mc.acceptEvent(generator.apply(mc)));
     }
 
     public <T extends Event & IModBusEvent> void postEvent(T e) {
@@ -295,7 +309,26 @@ public class ModLoader
             LOGGER.error("Cowardly refusing to send event {} to a broken mod state", e.getClass().getName());
             return;
         }
-        ModList.get().forEachModContainer((id, mc) -> mc.acceptEvent(e));
+        ModList.get().forEachModInOrder(mc -> mc.acceptEvent(e));
+    }
+    public <T extends Event & IModBusEvent> T postEventWithReturn(T e) {
+        if (!loadingStateValid) {
+            LOGGER.error("Cowardly refusing to send event {} to a broken mod state", e.getClass().getName());
+            return e;
+        }
+        ModList.get().forEachModInOrder(mc -> mc.acceptEvent(e));
+        return e;
+    }
+    public <T extends Event & IModBusEvent> void postEventWithWrapInModOrder(T e, BiConsumer<ModContainer, T> pre, BiConsumer<ModContainer, T> post) {
+        if (!loadingStateValid) {
+            LOGGER.error("Cowardly refusing to send event {} to a broken mod state", e.getClass().getName());
+            return;
+        }
+        ModList.get().forEachModInOrder(mc -> {
+            pre.accept(mc, e);
+            mc.acceptEvent(e);
+            post.accept(mc, e);
+        });
     }
 
     public List<ModLoadingWarning> getWarnings()

fmlcore/src/main/java/net/minecraftforge/fml/ModLoadingContext.java

@@ -1,31 +1,22 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;
 
+import com.mojang.logging.LogUtils;
 import net.minecraftforge.fml.config.IConfigSpec;
 import net.minecraftforge.fml.config.ModConfig;
+import net.minecraftforge.fml.loading.FMLLoader;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.util.function.Supplier;
 
 public class ModLoadingContext
 {
+    private static final Logger LOGGER = LogUtils.getLogger();
     private static final ThreadLocal<ModLoadingContext> context = ThreadLocal.withInitial(ModLoadingContext::new);
     private Object languageExtension;
     private ModLoadingStage stage;
@@ -60,10 +51,24 @@ public class ModLoadingContext
     }
 
     public void registerConfig(ModConfig.Type type, IConfigSpec<?> spec) {
+        if (spec.isEmpty())
+        {
+            // This handles the case where a mod tries to register a config, without any options configured inside it.
+            LOGGER.debug("Attempted to register an empty config for type {} on mod {}", type, getActiveContainer().getModId());
+            return;
+        }
+
         getActiveContainer().addConfig(new ModConfig(type, spec, getActiveContainer()));
     }
 
     public void registerConfig(ModConfig.Type type, IConfigSpec<?> spec, String fileName) {
+        if (spec.isEmpty())
+        {
+            // This handles the case where a mod tries to register a config, without any options configured inside it.
+            LOGGER.debug("Attempted to register an empty config for type {} on mod {} using file name {}", type, getActiveContainer().getModId(), fileName);
+            return;
+        }
+
         getActiveContainer().addConfig(new ModConfig(type, spec, getActiveContainer(), fileName));
     }
 

fmlcore/src/main/java/net/minecraftforge/fml/ModLoadingException.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;

fmlcore/src/main/java/net/minecraftforge/fml/ModLoadingPhase.java

@@ -1,9 +1,38 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.fml;
 
+/**
+ * Phases of mod loading, for grouping mod loading states.
+ */
 public enum ModLoadingPhase {
+    /**
+     * Special phase for exceptional situations and error handling, where mod loading cannot continue normally.
+     *
+     * <p>There is conventionally only one state with this phase.</p>
+     */
     ERROR, // Special state for error handling
+    /**
+     * Phase for discovering and gathering mods for loading.
+     */
     GATHER,
+    /**
+     * Phase for the loading of mods found from mod discovery.
+     *
+     * @see #GATHER
+     */
     LOAD,
+    /**
+     * Phase after mod loading has completed, for post-loading tasks.
+     *
+     * @see #LOAD
+     */
     COMPLETE,
-    DONE;
+    /**
+     * Marker phase for the last state in the full mod loading process.
+     */
+    DONE
 }

fmlcore/src/main/java/net/minecraftforge/fml/ModLoadingStage.java

@@ -1,34 +1,57 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;
 
+/**
+ * Mod loading stage of mod containers during the mod loading process. These will have a corresponding {@link ModLoadingState}
+ * in the basic mod loading process provided by FML.
+ *
+ * <p>Each mod loading stage has a global {@link DeferredWorkQueue}, which is populated during the execution of the state
+ * associated with this stage and emptied at the end of the state's execution.</p>
+ */
 public enum ModLoadingStage
 {
+    /**
+     * Special stage for exceptional situations and error handling.
+     */
     ERROR,
+    /**
+     * Validation of the mod list.
+     * TODO: figure out where this is used and why this exists instead of CONSTRUCT being the first normal stage
+     */
     VALIDATE,
+    /**
+     * Default stage of mod containers after construction.
+     */
     CONSTRUCT,
+    /**
+     * Common (non-side-specific) setup and initialization.
+     */
     COMMON_SETUP,
+    /**
+     * Side-specific setup and initialization.
+     *
+     * @see net.minecraftforge.api.distmarker.Dist
+     */
     SIDED_SETUP,
+    /**
+     * Stage for enqueuing {@link net.minecraftforge.fml.InterModComms} messages for later processing.
+     */
     ENQUEUE_IMC,
+    /**
+     * Stage for processing received messages though {@link net.minecraftforge.fml.InterModComms}.
+     */
     PROCESS_IMC,
+    /**
+     * Marks the completion of mod loading for this container.
+     */
     COMPLETE,
+    /**
+     * Marks the completion of the full mod loading process.
+     */
     DONE;
 
     private final DeferredWorkQueue deferredWorkQueue;
@@ -37,14 +60,27 @@ public enum ModLoadingStage
         deferredWorkQueue = new DeferredWorkQueue(this);
     }
 
+    /**
+     * {@return the next stage after this stage, or {@link #ERROR} if the exception is not {@code null}}
+     *
+     * @param exception the exception that occurred during this stage, may be {@code null}
+     */
     ModLoadingStage nextState(Throwable exception) {
         return exception != null ? ERROR : values()[this.ordinal()+1];
     }
 
+    /**
+     * {@return this stage, or {@link #ERROR} if the exception is not {@code null}}
+     *
+     * @param exception the exception that occurred during this stage, may be {@code null}
+     */
     public ModLoadingStage currentState(Throwable exception) {
         return exception != null ? ERROR : this;
     }
 
+    /**
+     * {@return the deferred work queue for this stage}
+     */
     public DeferredWorkQueue getDeferredWorkQueue() {
         return deferredWorkQueue;
     }

fmlcore/src/main/java/net/minecraftforge/fml/ModLoadingState.java

@@ -1,33 +1,98 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.fml;
 
 import net.minecraftforge.eventbus.api.Event;
 import net.minecraftforge.fml.event.IModBusEvent;
 
-import java.util.List;
 import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.Executor;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
-public record ModLoadingState(String name, String previous, Function<ModList, String> message, ModLoadingPhase phase, Optional<Consumer<ModList>> inlineRunnable, Optional<IModStateTransition> transition) implements IModLoadingState {
+/**
+ * Implementation of the {@link IModLoadingState} interface.
+ *
+ * @param name           the name of this state
+ * @param previous       the name of the state immediately previous to this state
+ * @param message        a function returning a human-friendly message for this state
+ * @param phase          the mod loading phase this state belongs to
+ * @param inlineRunnable an optional runnable, which runs before starting the transition from this state to the next
+ * @param transition     optional state transition information
+ */
+public record ModLoadingState(String name, String previous,
+                              Function<ModList, String> message,
+                              ModLoadingPhase phase,
+                              Optional<Consumer<ModList>> inlineRunnable,
+                              Optional<IModStateTransition> transition) implements IModLoadingState {
     @Override
-    public <T extends Event & IModBusEvent> Optional<CompletableFuture<List<Throwable>>> buildTransition(final Executor syncExecutor, final Executor parallelExecutor, Function<Executor, CompletableFuture<Void>> preSyncTask, Function<Executor, CompletableFuture<Void>> postSyncTask) {
-        return transition.map(t->t.build(syncExecutor, parallelExecutor, preSyncTask, postSyncTask));
+    public <T extends Event & IModBusEvent>
+    Optional<CompletableFuture<Void>> buildTransition(final Executor syncExecutor,
+                                                      final Executor parallelExecutor,
+                                                      final Function<Executor, CompletableFuture<Void>> preSyncTask,
+                                                      final Function<Executor, CompletableFuture<Void>> postSyncTask) {
+        return transition.map(t -> t.build(syncExecutor, parallelExecutor, preSyncTask, postSyncTask));
     }
 
+    /**
+     * {@return an empty mod loading state} The mod loading state has a blank human-readable message, no inline runnable,
+     * and no state transition information.
+     *
+     * @param name     the name of the state
+     * @param previous the name of the immediately previous state to this state
+     * @param phase    the mod loading phase the state belongs to
+     */
     public static ModLoadingState empty(final String name, final String previous, final ModLoadingPhase phase) {
-        return new ModLoadingState(name, previous, ml->"", phase, Optional.empty(), Optional.empty());
+        return new ModLoadingState(name, previous, ml -> "", phase, Optional.empty(), Optional.empty());
     }
 
-    public static ModLoadingState withTransition(final String name, final String previous, final ModLoadingPhase phase, IModStateTransition transition) {
-        return new ModLoadingState(name, previous, ml->"Processing transition "+name, phase, Optional.empty(), Optional.of(transition));
+    /**
+     * Returns a mod loading state with state transition information and a default human-friendly message of
+     * {@code Processing transition [name]}.
+     *
+     * @param name       the name of the state
+     * @param previous   the name of the immediately previous state to this state
+     * @param phase      the mod loading phase the state belongs to
+     * @param transition the state transition information
+     * @return a mod loading state with state transition information and a default message
+     */
+    public static ModLoadingState withTransition(final String name, final String previous, final ModLoadingPhase phase,
+                                                 final IModStateTransition transition) {
+        return new ModLoadingState(name, previous, ml -> "Processing transition " + name, phase, Optional.empty(), Optional.of(transition));
     }
 
-    public static ModLoadingState withTransition(final String name, final String previous, final Function<ModList, String> message, final ModLoadingPhase phase, IModStateTransition transition) {
+    /**
+     * Returns a mod loading state with state transition information and a custom human-friendly message function.
+     *
+     * @param name       the name of the state
+     * @param previous   the name of the immediately previous state to this state
+     * @param message    a function returning a human-friendly message for this state
+     * @param phase      the mod loading phase the state belongs to
+     * @param transition the state transition information
+     * @return a mod loading state with state transition information and a custom message
+     */
+    public static ModLoadingState withTransition(final String name, final String previous,
+                                                 final Function<ModList, String> message, final ModLoadingPhase phase,
+                                                 final IModStateTransition transition) {
         return new ModLoadingState(name, previous, message, phase, Optional.empty(), Optional.of(transition));
     }
-    public static ModLoadingState withInline(final String name, final String previous, final ModLoadingPhase phase, Consumer<ModList> inline) {
-        return new ModLoadingState(name, previous, ml->"Processing work "+name, phase, Optional.of(inline), Optional.empty());
+
+    /**
+     * Returns a mod loading state with an inline runnable and a default human-friendly message of {@code Processing
+     * work [name]}.
+     *
+     * @param name     the name of the state
+     * @param previous the name of the immediately previous state to this state
+     * @param phase    the mod loading phase the state belongs to
+     * @param inline   an optional runnable, which runs before starting the transition from this state to the next
+     * @return a mod loading state with an inline runnable and default message
+     */
+    public static ModLoadingState withInline(final String name, final String previous, final ModLoadingPhase phase,
+                                             final Consumer<ModList> inline) {
+        return new ModLoadingState(name, previous, ml -> "Processing work " + name, phase, Optional.of(inline), Optional.empty());
     }
 }

fmlcore/src/main/java/net/minecraftforge/fml/ModLoadingWarning.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;

fmlcore/src/main/java/net/minecraftforge/fml/ModStateManager.java

@@ -1,3 +1,8 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.fml;
 
 import com.google.common.graph.GraphBuilder;

fmlcore/src/main/java/net/minecraftforge/fml/ModWorkManager.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;

fmlcore/src/main/java/net/minecraftforge/fml/OptionalMod.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;

fmlcore/src/main/java/net/minecraftforge/fml/StartupMessageManager.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;

fmlcore/src/main/java/net/minecraftforge/fml/ThreadSelector.java

@@ -1,3 +1,8 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.fml;
 
 import java.util.concurrent.Executor;

fmlcore/src/main/java/net/minecraftforge/fml/VersionChecker.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml;
@@ -131,14 +117,22 @@ public class VersionChecker
             /**
              * Returns the response body as a String for the given URL while following redirects
              */
-            private String openUrlString(URL url) throws IOException, URISyntaxException, InterruptedException {
+            private String openUrlString(URL url, IModInfo mod) throws IOException, URISyntaxException, InterruptedException {
                 URL currentUrl = url;
+
+                final StringBuilder sb = new StringBuilder();
+                sb.append("Java-http-client/").append(System.getProperty("java.version")).append(' ');
+                sb.append("MinecraftForge/").append(FMLLoader.versionInfo().mcAndForgeVersion()).append(' ');
+                sb.append(mod.getModId()).append('/').append(mod.getVersion());
+                final String userAgent = sb.toString();
+
                 for (int redirects = 0; redirects < MAX_HTTP_REDIRECTS; redirects++)
                 {
                     var request = HttpRequest.newBuilder()
                             .uri(currentUrl.toURI())
                             .timeout(Duration.ofSeconds(HTTP_TIMEOUT_SECS))
                             .setHeader("Accept-Encoding", "gzip")
+                            .setHeader("User-Agent", userAgent)
                             .GET()
                             .build();
 
@@ -180,7 +174,7 @@ public class VersionChecker
                     URL url = mod.getUpdateURL().get();
                     LOGGER.info("[{}] Starting version check at {}", mod.getModId(), url.toString());
 
-                    String data = openUrlString(url);
+                    String data = openUrlString(url, mod);
 
                     LOGGER.debug("[{}] Received version check data:\n{}", mod.getModId(), data);
 

fmlcore/src/main/java/net/minecraftforge/fml/config/ConfigFileTypeHandler.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.config;
@@ -24,11 +10,11 @@ import com.electronwill.nightconfig.core.file.CommentedFileConfig;
 import com.electronwill.nightconfig.core.file.FileWatcher;
 import com.electronwill.nightconfig.core.io.ParsingException;
 import com.electronwill.nightconfig.core.io.WritingMode;
+import com.mojang.logging.LogUtils;
 import net.minecraftforge.fml.loading.FMLConfig;
 import net.minecraftforge.fml.loading.FMLPaths;
 import org.apache.commons.io.FilenameUtils;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import org.slf4j.Logger;
 
 import java.io.IOException;
 import java.nio.file.Files;
@@ -38,7 +24,7 @@ import java.util.function.Function;
 import static net.minecraftforge.fml.config.ConfigTracker.CONFIG;
 
 public class ConfigFileTypeHandler {
-    private static final Logger LOGGER = LogManager.getLogger();
+    private static final Logger LOGGER = LogUtils.getLogger();
     static ConfigFileTypeHandler TOML = new ConfigFileTypeHandler();
     private static final Path defaultConfigPath = FMLPaths.GAMEDIR.get().resolve(FMLConfig.defaultConfigPath());
 

fmlcore/src/main/java/net/minecraftforge/fml/config/ConfigTracker.java

@@ -1,38 +1,24 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.config;
 
 import com.electronwill.nightconfig.core.CommentedConfig;
 import com.electronwill.nightconfig.core.file.CommentedFileConfig;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
-import org.apache.logging.log4j.Marker;
-import org.apache.logging.log4j.MarkerManager;
+import com.mojang.logging.LogUtils;
+import org.slf4j.Logger;
+import org.slf4j.Marker;
+import org.slf4j.MarkerFactory;
 
 import java.nio.file.Path;
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 
 public class ConfigTracker {
-    private static final Logger LOGGER = LogManager.getLogger();
-    static final Marker CONFIG = MarkerManager.getMarker("CONFIG");
+    private static final Logger LOGGER = LogUtils.getLogger();
+    static final Marker CONFIG = MarkerFactory.getMarker("CONFIG");
     public static final ConfigTracker INSTANCE = new ConfigTracker();
     private final ConcurrentHashMap<String, ModConfig> fileMap;
     private final EnumMap<ModConfig.Type, Set<ModConfig>> configSets;

fmlcore/src/main/java/net/minecraftforge/fml/config/IConfigEvent.java

@@ -1,3 +1,8 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.fml.config;
 
 import net.minecraftforge.eventbus.api.Event;

fmlcore/src/main/java/net/minecraftforge/fml/config/IConfigSpec.java

@@ -1,3 +1,8 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.fml.config;
 
 import com.electronwill.nightconfig.core.CommentedConfig;

fmlcore/src/main/java/net/minecraftforge/fml/config/ModConfig.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2022.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.config;

fmlcore/src/main/java/net/minecraftforge/fml/event/IModBusEvent.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.event;

fmlcore/src/main/java/net/minecraftforge/fml/util/CertificateHelper.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.util;

fmlcore/src/main/java/net/minecraftforge/fml/util/EnhancedRuntimeException.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.util;

fmlcore/src/main/java/net/minecraftforge/fml/util/LoaderException.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.util;

fmlcore/src/main/java/net/minecraftforge/fml/util/LoaderExceptionModCrash.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.util;

fmlcore/src/main/java/net/minecraftforge/fml/util/ObfuscationReflectionHelper.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.util;

fmlcore/src/main/java/net/minecraftforge/fml/util/thread/EffectiveSide.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.util.thread;

fmlcore/src/main/java/net/minecraftforge/fml/util/thread/SidedThreadGroup.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.util.thread;

fmlcore/src/main/java/net/minecraftforge/fml/util/thread/SidedThreadGroups.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.util.thread;

fmlloader/build.gradle

@@ -1,6 +1,7 @@
 plugins {
     id 'com.github.ben-manes.versions'
     id 'org.javamodularity.moduleplugin' version '1.8.3' apply false
+    id 'org.cadixdev.licenser'
 }
 apply plugin: 'java-library'
 apply plugin: 'jacoco'
@@ -10,29 +11,36 @@ dependencyUpdates.rejectVersionIf { isNonStable(it.candidate.version) }
 configurations.forEach{ it.transitive = false }
 
 dependencies {
-    implementation('net.sf.jopt-simple:jopt-simple:5.0.4')
-    compileOnly('org.jetbrains:annotations:23.0.0')
+    compileOnly("org.jetbrains:annotations:${JETBRAINS_ANNOTATIONS_VERSION}")
+
     api("org.ow2.asm:asm:${ASM_VERSION}")
     api("org.ow2.asm:asm-tree:${ASM_VERSION}")
     api("org.ow2.asm:asm-commons:${ASM_VERSION}")
-    api('net.minecraftforge:forgespi:4.0.+')
-    api('org.apache.logging.log4j:log4j-api:2.17.0')
-    api('org.slf4j:slf4j-api:1.8.0-beta4')
-    api('com.google.guava:guava:21.0')
-    api('com.google.code.gson:gson:2.8.9')
-    api('org.apache.maven:maven-artifact:3.8.1')
-    api('org.apache.commons:commons-lang3:3.12.0')
-    api('com.electronwill.night-config:core:3.6.4')
-    api('com.electronwill.night-config:toml:3.6.4')
-    api('cpw.mods:modlauncher:9.0.+')
-    api('net.minecraftforge:coremods:5.0.+')
+    api("net.minecraftforge:forgespi:${SPI_VERSION}")
+    api("org.apache.logging.log4j:log4j-api:${LOG4J_VERSION}")
+    api("org.slf4j:slf4j-api:${SLF4J_API_VERSION}")
+    api("com.google.guava:guava:${GUAVA_VERSION}")
+    api("com.google.code.gson:gson:${GSON_VERSION}")
+    api("org.apache.maven:maven-artifact:${APACHE_MAVEN_ARTIFACT_VERSION}")
+    api("org.apache.commons:commons-lang3:${APACHE_COMMONS_LANG3_VERSION}")
+    api("com.electronwill.night-config:core:${NIGHTCONFIG_VERSION}")
+    api("com.electronwill.night-config:toml:${NIGHTCONFIG_VERSION}")
+    api("cpw.mods:modlauncher:${MODLAUNCHER_VERSION}")
+    api("net.minecraftforge:coremods:${COREMODS_VERSION}")
+    api("com.mojang:logging:${MOJANG_LOGGING_VERSION}")
+    api "net.minecraftforge:JarJarSelector:${JARJAR_VERSION}"
+    api "net.minecraftforge:JarJarMetadata:${JARJAR_VERSION}"
+
+    implementation("net.sf.jopt-simple:jopt-simple:${JOPT_SIMPLE_VERSION}")
     implementation("cpw.mods:securejarhandler:${SECUREJARHANDLER_VERSION}")
-    implementation('org.apache.logging.log4j:log4j-core:2.17.0')
-    annotationProcessor('org.apache.logging.log4j:log4j-core:2.17.0')
-    implementation('net.minecraftforge:accesstransformers:8.0.4')
-    implementation('net.minecrell:terminalconsoleappender:1.2.0')
-//    implementation('org.jline:jline:3.12.+')
-    testCompileOnly('org.jetbrains:annotations:21.0.0')
+    implementation("net.minecraftforge:accesstransformers:${ACCESSTRANSFORMERS_VERSION}")
+    implementation("net.minecrell:terminalconsoleappender:${TERMINALCONSOLEAPPENDER_VERSION}")
+    // implementation("org.jline:jline:${JLINE_VERSION}")
+
+    implementation("org.apache.logging.log4j:log4j-core:${LOG4J_VERSION}")
+    annotationProcessor("org.apache.logging.log4j:log4j-core:${LOG4J_VERSION}")
+
+    testCompileOnly("org.jetbrains:annotations:${JETBRAINS_ANNOTATIONS_VERSION}")
     testRuntimeOnly("cpw.mods:bootstraplauncher:${BOOTSTRAPLAUNCHER_VERSION}")
 }
 
@@ -70,6 +78,12 @@ tasks.withType(JavaCompile) {
     options.compilerArgs << '-Xlint:unchecked'
 }
 
+license {
+    header = rootProject.file('LICENSE-header.txt')
+
+    include 'net/minecraftforge/'
+}
+
 artifacts {
     archives jar
     archives sourcesJar

fmlloader/src/main/java/net/minecraftforge/fml/common/asm/CapabilityTokenSubclass.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.common.asm;

fmlloader/src/main/java/net/minecraftforge/fml/common/asm/ObjectHolderDefinalize.java

@@ -1,27 +1,17 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.common.asm;
 
 import java.util.EnumSet;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import org.objectweb.asm.Opcodes;
 import org.objectweb.asm.Type;
@@ -34,7 +24,17 @@ import cpw.mods.modlauncher.serviceapi.ILaunchPluginService;
  * Will also de-finalize all fields in on class level annotations.
  */
 public class ObjectHolderDefinalize implements ILaunchPluginService {
-
+    // Hardcoded map of vanilla classes that should have object holders for each field of the given registry type.
+    // IMPORTANT: Updates to this collection must be reflected in ObjectHolderRegistry. Duplicated cuz classloaders, yay!
+    // Classnames are validated in ObjectHolderRegistry.
+    private static final Map<String, VanillaObjectHolderData> VANILLA_OBJECT_HOLDERS = Stream.of(
+            new VanillaObjectHolderData("net.minecraft.world.level.block.Blocks", "block", "net.minecraft.world.level.block.Block"),
+            new VanillaObjectHolderData("net.minecraft.world.item.Items", "item", "net.minecraft.world.item.Item"),
+            new VanillaObjectHolderData("net.minecraft.world.item.enchantment.Enchantments", "enchantment", "net.minecraft.world.item.enchantment.Enchantment"),
+            new VanillaObjectHolderData("net.minecraft.world.effect.MobEffects", "mob_effect", "net.minecraft.world.effect.MobEffect"),
+            new VanillaObjectHolderData("net.minecraft.core.particles.ParticleTypes", "particle_type", "net.minecraft.core.particles.ParticleType"),
+            new VanillaObjectHolderData("net.minecraft.sounds.SoundEvents", "sound_event", "net.minecraft.sounds.SoundEvent")
+    ).collect(Collectors.toMap(VanillaObjectHolderData::holderClass, Function.identity()));
     private final String OBJECT_HOLDER = "Lnet/minecraftforge/registries/ObjectHolder;"; //Don't directly reference this to prevent class loading.
 
     @Override
@@ -42,7 +42,6 @@ public class ObjectHolderDefinalize implements ILaunchPluginService {
         return "object_holder_definalize";
     }
 
-
     private static final EnumSet<Phase> YAY = EnumSet.of(Phase.AFTER);
     private static final EnumSet<Phase> NAY = EnumSet.noneOf(Phase.class);
 
@@ -87,10 +86,8 @@ public class ObjectHolderDefinalize implements ILaunchPluginService {
             changes.compareAndSet(false, prev != f.access);
         });
 
-        if (hasHolder(classNode.visibleAnnotations)) //Class level, de-finalize all fields and add @ObjectHolder to them!
+        if (VANILLA_OBJECT_HOLDERS.containsKey(classType.getClassName())) //Class level, de-finalize all fields and add @ObjectHolder to them!
         {
-            @SuppressWarnings("unused")
-            String value = getValue(classNode.visibleAnnotations);
             classNode.fields.stream().filter(f -> ((f.access & flags) == flags) && f.desc.startsWith("L")).forEach(f ->
             {
                 int prev = f.access;
@@ -109,4 +106,5 @@ public class ObjectHolderDefinalize implements ILaunchPluginService {
         return changes.get() ? ComputeFlags.SIMPLE_REWRITE : ComputeFlags.NO_REWRITE;
     }
 
+    private record VanillaObjectHolderData(String holderClass, String registryName, String registryType) {}
 }

fmlloader/src/main/java/net/minecraftforge/fml/common/asm/RuntimeEnumExtender.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.common.asm;
@@ -23,9 +9,7 @@ import java.util.EnumSet;
 import java.util.List;
 import java.util.stream.Collectors;
 
-import net.minecraftforge.fml.loading.AdvancedLogMessageAdapter;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import com.mojang.logging.LogUtils;
 import org.objectweb.asm.Label;
 import org.objectweb.asm.Opcodes;
 import org.objectweb.asm.Type;
@@ -35,6 +19,9 @@ import org.objectweb.asm.tree.FieldNode;
 import org.objectweb.asm.tree.MethodNode;
 
 import cpw.mods.modlauncher.serviceapi.ILaunchPluginService;
+import org.slf4j.Logger;
+import org.slf4j.Marker;
+import org.slf4j.MarkerFactory;
 
 /**
  * Modifies specified enums to allow runtime extension by making the $VALUES field non-final and
@@ -42,7 +29,7 @@ import cpw.mods.modlauncher.serviceapi.ILaunchPluginService;
  */
 public class RuntimeEnumExtender implements ILaunchPluginService {
 
-    private static final Logger LOGGER = LogManager.getLogger();
+    private static final Logger LOGGER = LogUtils.getLogger();
     private final Type STRING = Type.getType(String.class);
     private final Type ENUM = Type.getType(Enum.class);
     private final Type MARKER_IFACE = Type.getType("Lnet/minecraftforge/common/IExtensibleEnum;");
@@ -77,43 +64,49 @@ public class RuntimeEnumExtender implements ILaunchPluginService {
         final int flags = Opcodes.ACC_PRIVATE | Opcodes.ACC_STATIC | Opcodes.ACC_FINAL | Opcodes.ACC_SYNTHETIC;
 
         FieldNode values = classNode.fields.stream().filter(f -> f.desc.contentEquals(array.getDescriptor()) && ((f.access & flags) == flags)).findFirst().orElse(null);
-        
+
         if (!classNode.interfaces.contains(MARKER_IFACE.getInternalName())) {
             return ComputeFlags.NO_REWRITE;
         }
-        
+
         //Static methods named "create" with first argument as a string
         List<MethodNode> candidates = classNode.methods.stream()
                 .filter(m -> ((m.access & Opcodes.ACC_STATIC) != 0) && m.name.equals("create"))
                 .collect(Collectors.toList());
-        
+
         if (candidates.isEmpty()) {
             throw new IllegalStateException("IExtensibleEnum has no candidate factory methods: " + classType.getClassName());
         }
-        
+
         candidates.forEach(mtd ->
         {
             Type[] args = Type.getArgumentTypes(mtd.desc);
             if (args.length == 0 || !args[0].equals(STRING)) {
-                LOGGER.fatal(()->new AdvancedLogMessageAdapter(sb-> {
+                if (LOGGER.isErrorEnabled(LogUtils.FATAL_MARKER))
+                {
+                    StringBuilder sb = new StringBuilder();
                     sb.append("Enum has create method without String as first parameter:\n");
                     sb.append("  Enum: ").append(classType.getDescriptor()).append("\n");
                     sb.append("  Target: ").append(mtd.name).append(mtd.desc).append("\n");
-                }));
+                    LOGGER.error(LogUtils.FATAL_MARKER, sb.toString());
+                }
                 throw new IllegalStateException("Enum has create method without String as first parameter: " + mtd.name + mtd.desc);
             }
 
             Type ret = Type.getReturnType(mtd.desc);
             if (!ret.equals(classType)) {
-                LOGGER.fatal(()->new AdvancedLogMessageAdapter(sb-> {
+                if (LOGGER.isErrorEnabled(LogUtils.FATAL_MARKER))
+                {
+                    StringBuilder sb = new StringBuilder();
                     sb.append("Enum has create method with incorrect return type:\n");
                     sb.append("  Enum: ").append(classType.getDescriptor()).append("\n");
                     sb.append("  Target: ").append(mtd.name).append(mtd.desc).append("\n");
                     sb.append("  Found: ").append(ret.getClassName()).append(", Expected: ").append(classType.getClassName());
-                }));
+                    LOGGER.error(LogUtils.FATAL_MARKER, sb.toString());
+                }
                 throw new IllegalStateException("Enum has create method with incorrect return type: " + mtd.name + mtd.desc);
             }
-            
+
             Type[] ctrArgs = new Type[args.length + 1];
             ctrArgs[0] = STRING;
             ctrArgs[1] = Type.INT_TYPE;
@@ -125,23 +118,29 @@ public class RuntimeEnumExtender implements ILaunchPluginService {
             MethodNode ctr = classNode.methods.stream().filter(m -> m.name.equals("<init>") && m.desc.equals(desc)).findFirst().orElse(null);
             if (ctr == null)
             {
-                LOGGER.fatal(()->new AdvancedLogMessageAdapter(sb-> {
+                if (LOGGER.isErrorEnabled(LogUtils.FATAL_MARKER))
+                {
+                    StringBuilder sb = new StringBuilder();
                     sb.append("Enum has create method with no matching constructor:\n");
                     sb.append("  Enum: ").append(classType.getDescriptor()).append("\n");
                     sb.append("  Candidate: ").append(mtd.desc).append("\n");
                     sb.append("  Target: ").append(desc).append("\n");
                     classNode.methods.stream().filter(m -> m.name.equals("<init>")).forEach(m -> sb.append("        : ").append(m.desc).append("\n"));
-                }));
+                    LOGGER.error(LogUtils.FATAL_MARKER, sb.toString());
+                }
                 throw new IllegalStateException("Enum has create method with no matching constructor: " + desc);
             }
 
             if (values == null)
             {
-                LOGGER.fatal(()->new AdvancedLogMessageAdapter(sb-> {
+                if (LOGGER.isErrorEnabled(LogUtils.FATAL_MARKER))
+                {
+                    StringBuilder sb = new StringBuilder();
                     sb.append("Enum has create method but we could not find $VALUES. Found:\n");
                     classNode.fields.stream().filter(f -> (f.access & Opcodes.ACC_STATIC) != 0).
                             forEach(m -> sb.append("  ").append(m.name).append(" ").append(m.desc).append("\n"));
-                }));
+                    LOGGER.error(LogUtils.FATAL_MARKER, sb.toString());
+                }
                 throw new IllegalStateException("Enum has create method but we could not find $VALUES");
             }
 
@@ -149,6 +148,19 @@ public class RuntimeEnumExtender implements ILaunchPluginService {
 
             mtd.access |= Opcodes.ACC_SYNCHRONIZED;
             mtd.instructions.clear();
+            mtd.localVariables.clear();
+            if (mtd.tryCatchBlocks != null)
+            {
+                mtd.tryCatchBlocks.clear();
+            }
+            if (mtd.visibleLocalVariableAnnotations != null)
+            {
+                mtd.visibleLocalVariableAnnotations.clear();
+            }
+            if (mtd.invisibleLocalVariableAnnotations != null)
+            {
+                mtd.invisibleLocalVariableAnnotations.clear();
+            }
             InstructionAdapter ins = new InstructionAdapter(mtd);
 
             int vars = 0;

fmlloader/src/main/java/net/minecraftforge/fml/loading/AdvancedLogMessageAdapter.java

@@ -1,62 +0,0 @@
-/*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
- */
-
-package net.minecraftforge.fml.loading;
-
-import org.apache.logging.log4j.message.Message;
-import org.apache.logging.log4j.util.StringBuilderFormattable;
-
-import java.util.function.Consumer;
-
-public class AdvancedLogMessageAdapter implements Message, StringBuilderFormattable {
-    private static final long serialVersionUID = -8291754833965087436L;
-
-    private static final Object[] EMPTY = new Object[0];
-
-    private final Consumer<StringBuilder> logMessageBuilder;
-
-    public AdvancedLogMessageAdapter(final Consumer<StringBuilder> logMessageBuilder) {
-        this.logMessageBuilder = logMessageBuilder;
-    }
-
-    @Override
-    public String getFormattedMessage() {
-        return "";
-    }
-
-    @Override
-    public String getFormat() {
-        return "";
-    }
-
-    @Override
-    public Object[] getParameters() {
-        return EMPTY;
-    }
-
-    @Override
-    public Throwable getThrowable() {
-        return null;
-    }
-
-    @Override
-    public void formatTo(final StringBuilder buffer) {
-        logMessageBuilder.accept(buffer);
-    }
-}

fmlloader/src/main/java/net/minecraftforge/fml/loading/BackgroundWaiter.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;

fmlloader/src/main/java/net/minecraftforge/fml/loading/ClasspathLocatorUtils.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.minecraftforge.fml.loading;
+
+import com.mojang.logging.LogUtils;
+import org.slf4j.Logger;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.URL;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+public class ClasspathLocatorUtils {
+    
+    private static final Logger LOGGER = LogUtils.getLogger();
+
+    public static Path findJarPathFor(final String resourceName, final String jarName, final URL resource) {
+        try {
+            Path path;
+            final URI uri = resource.toURI();
+            if (uri.getScheme().equals("jar") && uri.getRawSchemeSpecificPart().contains("!/")) {
+                int lastExcl = uri.getRawSchemeSpecificPart().lastIndexOf("!/");
+                path = Paths.get(new URI(uri.getRawSchemeSpecificPart().substring(0, lastExcl)));
+            } else {
+                path = Paths.get(new URI("file://"+uri.getRawSchemeSpecificPart().substring(0, uri.getRawSchemeSpecificPart().length()-resourceName.length())));
+            }
+            //LOGGER.debug(CORE, "Found JAR {} at path {}", jarName, path.toString());
+            return path;
+        } catch (NullPointerException | URISyntaxException e) {
+            LOGGER.error(LogMarkers.SCAN, "Failed to find JAR for class {} - {}", resourceName, jarName);
+            throw new RuntimeException("Unable to locate "+resourceName+" - "+jarName, e);
+        }
+    }
+}

fmlloader/src/main/java/net/minecraftforge/fml/loading/ClasspathTransformerDiscoverer.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.minecraftforge.fml.loading;
+
+import cpw.mods.modlauncher.api.NamedPath;
+import cpw.mods.modlauncher.serviceapi.ITransformerDiscoveryService;
+import org.apache.logging.log4j.LogManager;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.URL;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.*;
+
+public class ClasspathTransformerDiscoverer implements ITransformerDiscoveryService {
+
+    private final List<Path> legacyClasspath = Arrays.stream(System.getProperty("legacyClassPath", "").split(File.pathSeparator)).map(Path::of).toList();
+
+    @Override
+    public List<NamedPath> candidates(Path gameDirectory) {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public List<NamedPath> candidates(final Path gameDirectory, final String launchTarget) {
+        if (launchTarget != null && launchTarget.contains("dev")) {
+            this.scan(gameDirectory);
+        }
+        return List.copyOf(found);
+    }
+
+    private final static List<NamedPath> found = new ArrayList<>();
+
+    public static List<Path> allExcluded() {
+        return found.stream().map(np->np.paths()[0]).toList();
+    }
+    
+    private void scan(final Path gameDirectory) {
+        try {
+            locateTransformers("META-INF/services/cpw.mods.modlauncher.api.ITransformationService");
+            locateTransformers("META-INF/services/net.minecraftforge.forgespi.locating.IModLocator");
+        } catch (IOException e) {
+            LogManager.getLogger().error("Error during discovery of transform services from the classpath", e);
+        }
+    }
+
+    private void locateTransformers(String resource) throws IOException {
+        final Enumeration<URL> resources = ClassLoader.getSystemClassLoader().getResources(resource);
+        while (resources.hasMoreElements()) {
+            URL url = resources.nextElement();
+            Path path = ClasspathLocatorUtils.findJarPathFor(resource, url.toString(), url);
+            if (legacyClasspath.stream().anyMatch(path::equals) || !Files.exists(path) || Files.isDirectory(path))
+                continue;
+            found.add(new NamedPath(path.toUri().toString(), path));
+        }
+    }
+}

fmlloader/src/main/java/net/minecraftforge/fml/loading/EarlyLoadingException.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;
@@ -61,7 +47,7 @@ public class EarlyLoadingException extends RuntimeException {
         return errorMessages;
     }
 
-    EarlyLoadingException(final String message, final Throwable originalException, List<ExceptionData> errorMessages) {
+    public EarlyLoadingException(final String message, final Throwable originalException, List<ExceptionData> errorMessages) {
         super(message, originalException);
         this.errorMessages = errorMessages;
     }

fmlloader/src/main/java/net/minecraftforge/fml/loading/FMLConfig.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;
@@ -24,8 +10,8 @@ import com.electronwill.nightconfig.core.file.CommentedFileConfig;
 import com.electronwill.nightconfig.core.file.FileNotFoundAction;
 import com.electronwill.nightconfig.core.io.ParsingException;
 import com.electronwill.nightconfig.core.io.WritingMode;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import com.mojang.logging.LogUtils;
+import org.slf4j.Logger;
 
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -35,7 +21,7 @@ import static net.minecraftforge.fml.loading.LogMarkers.CORE;
 
 public class FMLConfig
 {
-    private static final Logger LOGGER = LogManager.getLogger();
+    private static final Logger LOGGER = LogUtils.getLogger();
     private static FMLConfig INSTANCE = new FMLConfig();
     private static ConfigSpec configSpec = new ConfigSpec();
     static {
@@ -43,6 +29,7 @@ public class FMLConfig
         configSpec.define("maxThreads", -1);
         configSpec.define("versionCheck", Boolean.TRUE);
         configSpec.define("defaultConfigPath",  "defaultconfigs");
+        configSpec.define("disableOptimizedDFU", Boolean.TRUE);
     }
 
     private CommentedFileConfig configData;
@@ -74,11 +61,14 @@ public class FMLConfig
     {
         final Path configFile = FMLPaths.FMLCONFIG.get();
         INSTANCE.loadFrom(configFile);
-        LOGGER.trace(CORE, "Loaded FML config from {}", FMLPaths.FMLCONFIG.get());
-        LOGGER.trace(CORE, "Splash screen is {}", FMLConfig::splashScreenEnabled);
-        LOGGER.trace(CORE, "Max threads for mod loading computed at {}", FMLConfig::loadingThreadCount);
-        LOGGER.trace(CORE, "Version check is {}", FMLConfig::runVersionCheck);
-        LOGGER.trace(CORE, "Default config paths at {}", FMLConfig::defaultConfigPath);
+        if (LOGGER.isTraceEnabled(CORE))
+        {
+            LOGGER.trace(CORE, "Loaded FML config from {}", FMLPaths.FMLCONFIG.get());
+            LOGGER.trace(CORE, "Splash screen is {}", FMLConfig.splashScreenEnabled());
+            LOGGER.trace(CORE, "Max threads for mod loading computed at {}", FMLConfig.loadingThreadCount());
+            LOGGER.trace(CORE, "Version check is {}", FMLConfig.runVersionCheck());
+            LOGGER.trace(CORE, "Default config paths at {}", FMLConfig.defaultConfigPath());
+        }
         FMLPaths.getOrCreateGameRelativePath(Paths.get(FMLConfig.defaultConfigPath()), "default config directory");
     }
 
@@ -99,4 +89,8 @@ public class FMLConfig
     public static String defaultConfigPath() {
         return INSTANCE.configData.<String>getOptional("defaultConfigPath").orElse("defaultconfigs");
     }
+
+    public static boolean isOptimizedDFUDisabled() {
+        return INSTANCE.configData.<Boolean>getOptional("disableOptimizedDFU").orElse(Boolean.TRUE);
+    }
 }

fmlloader/src/main/java/net/minecraftforge/fml/loading/FMLEnvironment.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;

fmlloader/src/main/java/net/minecraftforge/fml/loading/FMLLoader.java

@@ -1,24 +1,11 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;
 
+import com.mojang.logging.LogUtils;
 import cpw.mods.modlauncher.Launcher;
 import cpw.mods.modlauncher.api.*;
 import cpw.mods.modlauncher.serviceapi.ILaunchPluginService;
@@ -35,8 +22,7 @@ import net.minecraftforge.fml.loading.targets.CommonLaunchHandler;
 import net.minecraftforge.forgespi.Environment;
 import net.minecraftforge.forgespi.coremod.ICoreModProvider;
 import org.apache.commons.lang3.tuple.Pair;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import org.slf4j.Logger;
 
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -49,7 +35,7 @@ import static net.minecraftforge.fml.loading.LogMarkers.SCAN;
 
 public class FMLLoader
 {
-    private static final Logger LOGGER = LogManager.getLogger();
+    private static final Logger LOGGER = LogUtils.getLogger();
     private static AccessTransformerService accessTransformer;
     private static ModDiscoverer modDiscoverer;
     private static ICoreModProvider coreModProvider;
@@ -76,47 +62,47 @@ public class FMLLoader
         final Package modLauncherPackage = ITransformationService.class.getPackage();
         LOGGER.debug(CORE,"FML found ModLauncher version : {}", modLauncherPackage.getImplementationVersion());
         if (!modLauncherPackage.isCompatibleWith("4.0")) {
-            LOGGER.fatal(CORE,"Found incompatible ModLauncher specification : {}, version {} from {}", modLauncherPackage.getSpecificationVersion(), modLauncherPackage.getImplementationVersion(), modLauncherPackage.getImplementationVendor());
+            LOGGER.error(CORE, "Found incompatible ModLauncher specification : {}, version {} from {}", modLauncherPackage.getSpecificationVersion(), modLauncherPackage.getImplementationVersion(), modLauncherPackage.getImplementationVendor());
             throw new IncompatibleEnvironmentException("Incompatible modlauncher found "+modLauncherPackage.getSpecificationVersion());
         }
 
         accessTransformer = (AccessTransformerService) environment.findLaunchPlugin("accesstransformer").orElseThrow(()-> {
-            LOGGER.fatal(CORE,"Access Transformer library is missing, we need this to run");
+            LOGGER.error(CORE, "Access Transformer library is missing, we need this to run");
             return new IncompatibleEnvironmentException("Missing AccessTransformer, cannot run");
         });
 
         final Package atPackage = accessTransformer.getClass().getPackage();
         LOGGER.debug(CORE,"FML found AccessTransformer version : {}", atPackage.getImplementationVersion());
         if (!atPackage.isCompatibleWith("1.0")) {
-            LOGGER.fatal(CORE,"Found incompatible AccessTransformer specification : {}, version {} from {}", atPackage.getSpecificationVersion(), atPackage.getImplementationVersion(), atPackage.getImplementationVendor());
+            LOGGER.error(CORE, "Found incompatible AccessTransformer specification : {}, version {} from {}", atPackage.getSpecificationVersion(), atPackage.getImplementationVersion(), atPackage.getImplementationVendor());
             throw new IncompatibleEnvironmentException("Incompatible accesstransformer found "+atPackage.getSpecificationVersion());
         }
 
         eventBus = environment.findLaunchPlugin("eventbus").orElseThrow(()-> {
-            LOGGER.fatal(CORE,"Event Bus library is missing, we need this to run");
+            LOGGER.error(CORE, "Event Bus library is missing, we need this to run");
             return new IncompatibleEnvironmentException("Missing EventBus, cannot run");
         });
 
         final Package eventBusPackage = eventBus.getClass().getPackage();
         LOGGER.debug(CORE,"FML found EventBus version : {}", eventBusPackage.getImplementationVersion());
         if (!eventBusPackage.isCompatibleWith("1.0")) {
-            LOGGER.fatal(CORE,"Found incompatible EventBus specification : {}, version {} from {}", eventBusPackage.getSpecificationVersion(), eventBusPackage.getImplementationVersion(), eventBusPackage.getImplementationVendor());
+            LOGGER.error(CORE, "Found incompatible EventBus specification : {}, version {} from {}", eventBusPackage.getSpecificationVersion(), eventBusPackage.getImplementationVersion(), eventBusPackage.getImplementationVendor());
             throw new IncompatibleEnvironmentException("Incompatible eventbus found "+eventBusPackage.getSpecificationVersion());
         }
 
         runtimeDistCleaner = (RuntimeDistCleaner)environment.findLaunchPlugin("runtimedistcleaner").orElseThrow(()-> {
-            LOGGER.fatal(CORE,"Dist Cleaner is missing, we need this to run");
+            LOGGER.error(CORE, "Dist Cleaner is missing, we need this to run");
             return new IncompatibleEnvironmentException("Missing DistCleaner, cannot run!");
         });
         LOGGER.debug(CORE, "Found Runtime Dist Cleaner");
 
-        var coreModProviders = ServiceLoaderUtils.streamWithErrorHandling(ServiceLoader.load(FMLLoader.class.getModule().getLayer(), ICoreModProvider.class), sce -> LOGGER.fatal(CORE, "Failed to load a coremod library, expect problems", sce)).toList();
+        var coreModProviders = ServiceLoaderUtils.streamWithErrorHandling(ServiceLoader.load(FMLLoader.class.getModule().getLayer(), ICoreModProvider.class), sce -> LOGGER.error(CORE, "Failed to load a coremod library, expect problems", sce)).toList();
 
         if (coreModProviders.isEmpty()) {
-            LOGGER.fatal(CORE, "Found no coremod provider. Cannot run");
+            LOGGER.error(CORE, "Found no coremod provider. Cannot run");
             throw new IncompatibleEnvironmentException("No coremod library found");
         } else if (coreModProviders.size() > 1) {
-            LOGGER.fatal(CORE, "Found multiple coremod providers : {}. Cannot run", coreModProviders.stream().map(p -> p.getClass().getName()).collect(Collectors.toList()));
+            LOGGER.error(CORE, "Found multiple coremod providers : {}. Cannot run", coreModProviders.stream().map(p -> p.getClass().getName()).collect(Collectors.toList()));
             throw new IncompatibleEnvironmentException("Multiple coremod libraries found");
         }
 
@@ -128,7 +114,7 @@ public class FMLLoader
         LOGGER.debug(CORE, "Found ForgeSPI package implementation version {}", Environment.class.getPackage().getImplementationVersion());
         LOGGER.debug(CORE, "Found ForgeSPI package specification {}", Environment.class.getPackage().getSpecificationVersion());
         if (Integer.parseInt(Environment.class.getPackage().getSpecificationVersion()) < 2) {
-            LOGGER.fatal(CORE, "Found an out of date ForgeSPI implementation: {}, loading cannot continue", Environment.class.getPackage().getSpecificationVersion());
+            LOGGER.error(CORE, "Found an out of date ForgeSPI implementation: {}, loading cannot continue", Environment.class.getPackage().getSpecificationVersion());
             throw new IncompatibleEnvironmentException("ForgeSPI is out of date, we cannot continue");
         }
 
@@ -136,7 +122,7 @@ public class FMLLoader
             Class.forName("com.electronwill.nightconfig.core.Config", false, environment.getClass().getClassLoader());
             Class.forName("com.electronwill.nightconfig.toml.TomlFormat", false, environment.getClass().getClassLoader());
         } catch (ClassNotFoundException e) {
-            LOGGER.fatal(CORE, "Failed to load NightConfig");
+            LOGGER.error(CORE, "Failed to load NightConfig");
             throw new IncompatibleEnvironmentException("Missing NightConfig");
         }
     }
@@ -148,12 +134,12 @@ public class FMLLoader
         final Optional<ILaunchHandlerService> launchHandler = environment.findLaunchHandler(launchTarget);
         LOGGER.debug(CORE, "Using {} as launch service", launchTarget);
         if (launchHandler.isEmpty()) {
-            LOGGER.fatal(CORE,"Missing LaunchHandler {}, cannot continue", launchTarget);
+            LOGGER.error(CORE, "Missing LaunchHandler {}, cannot continue", launchTarget);
             throw new RuntimeException("Missing launch handler: " + launchTarget);
         }
 
         if (!(launchHandler.get() instanceof CommonLaunchHandler)) {
-            LOGGER.fatal(CORE, "Incompatible Launch handler found - type {}, cannot continue", launchHandler.get().getClass().getName());
+            LOGGER.error(CORE, "Incompatible Launch handler found - type {}, cannot continue", launchHandler.get().getClass().getName());
             throw new RuntimeException("Incompatible launch handler found");
         }
         commonLaunchHandler = (CommonLaunchHandler)launchHandler.get();

fmlloader/src/main/java/net/minecraftforge/fml/loading/FMLPaths.java

@@ -1,27 +1,13 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;
 
+import com.mojang.logging.LogUtils;
 import cpw.mods.modlauncher.api.IEnvironment;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import org.slf4j.Logger;
 
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -36,7 +22,7 @@ public enum FMLPaths
     CONFIGDIR("config"),
     FMLCONFIG(false, CONFIGDIR, "fml.toml");
 
-    private static final Logger LOGGER = LogManager.getLogger();
+    private static final Logger LOGGER = LogUtils.getLogger();
     private final Path relativePath;
     private final boolean isDirectory;
     private Path absolutePath;
@@ -75,7 +61,10 @@ public enum FMLPaths
             {
                 FileUtils.getOrCreateDirectory(path.absolutePath, path.name());
             }
-            LOGGER.debug(CORE,"Path {} is {}", ()-> path, ()-> path.absolutePath);
+            if (LOGGER.isDebugEnabled(CORE))
+            {
+                LOGGER.debug(CORE, "Path {} is {}", path, path.absolutePath);
+            }
         }
     }
 

fmlloader/src/main/java/net/minecraftforge/fml/loading/FMLServiceProvider.java

@@ -1,32 +1,18 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;
 
+import com.mojang.logging.LogUtils;
 import cpw.mods.modlauncher.api.*;
 import joptsimple.ArgumentAcceptingOptionSpec;
 import joptsimple.OptionSpecBuilder;
 import net.minecraftforge.fml.loading.moddiscovery.ModFile;
 import net.minecraftforge.forgespi.Environment;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
 import org.jetbrains.annotations.NotNull;
+import org.slf4j.Logger;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -40,7 +26,7 @@ import static net.minecraftforge.fml.loading.LogMarkers.CORE;
 
 public class FMLServiceProvider implements ITransformationService
 {
-    private static final Logger LOGGER = LogManager.getLogger();
+    private static final Logger LOGGER = LogUtils.getLogger();
     private ArgumentAcceptingOptionSpec<String> modsOption;
     private ArgumentAcceptingOptionSpec<String> modListsOption;
     private ArgumentAcceptingOptionSpec<String> mavenRootsOption;

fmlloader/src/main/java/net/minecraftforge/fml/loading/FileUtils.java

@@ -1,27 +1,14 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import com.mojang.logging.LogUtils;
+import org.slf4j.Logger;
 
+import java.io.File;
 import java.io.IOException;
 import java.nio.file.FileAlreadyExistsException;
 import java.nio.file.Files;
@@ -31,7 +18,7 @@ import static net.minecraftforge.fml.loading.LogMarkers.CORE;
 
 public class FileUtils
 {
-    private static final Logger LOGGER = LogManager.getLogger();
+    private static final Logger LOGGER = LogUtils.getLogger();
 
     public static Path getOrCreateDirectory(Path dirPath, String dirLabel) {
         if (!Files.isDirectory(dirPath.getParent())) {
@@ -39,20 +26,20 @@ public class FileUtils
         }
         if (!Files.isDirectory(dirPath))
         {
-            LOGGER.debug(CORE,"Making {} directory : {}", dirLabel, dirPath);
+            LOGGER.debug(CORE, "Making {} directory : {}", dirLabel, dirPath);
             try {
                 Files.createDirectory(dirPath);
             } catch (IOException e) {
                 if (e instanceof FileAlreadyExistsException) {
-                    LOGGER.fatal(CORE,"Failed to create {} directory - there is a file in the way", dirLabel);
+                    LOGGER.error(CORE, "Failed to create {} directory - there is a file in the way", dirLabel);
                 } else {
-                    LOGGER.fatal(CORE,"Problem with creating {} directory (Permissions?)", dirLabel, e);
+                    LOGGER.error(CORE, "Problem with creating {} directory (Permissions?)", dirLabel, e);
                 }
                 throw new RuntimeException("Problem creating directory", e);
             }
-            LOGGER.debug(CORE,"Created {} directory : {}", dirLabel, dirPath);
+            LOGGER.debug(CORE, "Created {} directory : {}", dirLabel, dirPath);
         } else {
-            LOGGER.debug(CORE,"Found existing {} directory : {}", dirLabel, dirPath);
+            LOGGER.debug(CORE, "Found existing {} directory : {}", dirLabel, dirPath);
         }
         return dirPath;
     }
@@ -67,4 +54,16 @@ public class FileUtils
             return "";
         }
     }
+    
+    public static boolean matchFileName(String path, String... matches) {
+        // Extract file name from path
+        String name = path.substring(Math.min(path.lastIndexOf(File.separatorChar) + 1, path.length()));
+        // Check if it contains any of the desired keywords
+        for (String match : matches) {
+            if (name.contains(match)) {
+                return true;
+            }
+        }
+        return false;
+    }
 }

fmlloader/src/main/java/net/minecraftforge/fml/loading/JarVersionLookupHandler.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;

fmlloader/src/main/java/net/minecraftforge/fml/loading/LanguageLoadingProvider.java

@@ -1,24 +1,11 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;
 
+import com.mojang.logging.LogUtils;
 import cpw.mods.modlauncher.Launcher;
 import cpw.mods.modlauncher.api.IModuleLayerManager;
 import cpw.mods.modlauncher.util.ServiceLoaderUtils;
@@ -26,11 +13,10 @@ import net.minecraftforge.fml.loading.progress.StartupMessageManager;
 import net.minecraftforge.forgespi.language.IModLanguageProvider;
 import net.minecraftforge.fml.loading.moddiscovery.ExplodedDirectoryLocator;
 import net.minecraftforge.fml.loading.moddiscovery.ModFile;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
 import org.apache.maven.artifact.versioning.ArtifactVersion;
 import org.apache.maven.artifact.versioning.DefaultArtifactVersion;
 import org.apache.maven.artifact.versioning.VersionRange;
+import org.slf4j.Logger;
 
 import java.net.URISyntaxException;
 import java.nio.file.Files;
@@ -52,7 +38,7 @@ import static net.minecraftforge.fml.loading.LogMarkers.LOADING;
 
 public class LanguageLoadingProvider
 {
-    private static final Logger LOGGER = LogManager.getLogger();
+    private static final Logger LOGGER = LogUtils.getLogger();
     private final List<IModLanguageProvider> languageProviders = new ArrayList<>();
     private final ServiceLoader<IModLanguageProvider> serviceLoader;
     private final Map<String, ModLanguageWrapper> languageProviderMap = new HashMap<>();
@@ -95,7 +81,7 @@ public class LanguageLoadingProvider
         loadLanguageProviders();
     }
     private void loadLanguageProviders() {
-        LOGGER.debug(CORE, "Found {} language providers", ServiceLoaderUtils.streamServiceLoader(()->serviceLoader, sce->LOGGER.fatal("Problem with language loaders")).count());
+        LOGGER.debug(CORE, "Found {} language providers", ServiceLoaderUtils.streamServiceLoader(()->serviceLoader, sce->LOGGER.error("Problem with language loaders")).count());
         serviceLoader.forEach(languageProviders::add);
 
         languageProviders.forEach(lp -> {
@@ -108,7 +94,7 @@ public class LanguageLoadingProvider
             Optional<String> implementationVersion = JarVersionLookupHandler.getImplementationVersion(lp.getClass());
             String impl = implementationVersion.orElse(Files.isDirectory(lpPath) ? FMLLoader.versionInfo().forgeVersion().split("\\.")[0] : null);
             if (impl == null) {
-                LOGGER.fatal(CORE, "Found unversioned language provider {}", lp.name());
+                LOGGER.error(CORE, "Found unversioned language provider {}", lp.name());
                 throw new RuntimeException("Failed to find implementation version for language provider "+ lp.name());
             }
             LOGGER.debug(CORE, "Found language provider {}, version {}", lp.name(), impl);
@@ -148,7 +134,7 @@ public class LanguageLoadingProvider
     }
 
     public IModLanguageProvider findLanguage(ModFile mf, String modLoader, VersionRange modLoaderVersion) {
-        final String languageFileName = mf.getLocator() instanceof ExplodedDirectoryLocator ? "in-development" : mf.getFileName();
+        final String languageFileName = mf.getProvider() instanceof ExplodedDirectoryLocator ? "in-development" : mf.getFileName();
         final ModLanguageWrapper mlw = languageProviderMap.get(modLoader);
         if (mlw == null) {
             LOGGER.error(LOADING,"Missing language {} version {} wanted by {}", modLoader, modLoaderVersion, languageFileName);

fmlloader/src/main/java/net/minecraftforge/fml/loading/LauncherVersion.java

@@ -1,31 +1,17 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import com.mojang.logging.LogUtils;
+import org.slf4j.Logger;
 
 import static net.minecraftforge.fml.loading.LogMarkers.CORE;
 
 public class LauncherVersion {
-    private static final Logger LOGGER = LogManager.getLogger();
+    private static final Logger LOGGER = LogUtils.getLogger();
     private static final String launcherVersion;
 
     static {

fmlloader/src/main/java/net/minecraftforge/fml/loading/LibraryFinder.java

@@ -1,32 +1,18 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import com.mojang.logging.LogUtils;
+import org.slf4j.Logger;
 
 import java.nio.file.Files;
 import java.nio.file.Path;
 
 public class LibraryFinder {
-    private static final Logger LOGGER = LogManager.getLogger();
+    private static final Logger LOGGER = LogUtils.getLogger();
     private static Path libsPath;
     static Path findLibsPath() {
         if (libsPath == null) {

fmlloader/src/main/java/net/minecraftforge/fml/loading/LoadingModList.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;
@@ -24,11 +10,18 @@ import net.minecraftforge.fml.loading.moddiscovery.BackgroundScanHandler;
 import net.minecraftforge.fml.loading.moddiscovery.ModFile;
 import net.minecraftforge.fml.loading.moddiscovery.ModFileInfo;
 import net.minecraftforge.fml.loading.moddiscovery.ModInfo;
+import net.minecraftforge.forgespi.locating.IModFile;
 
 import java.net.URL;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Enumeration;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.NoSuchElementException;
 import java.util.stream.Collectors;
 
 /**
@@ -42,7 +35,7 @@ public class LoadingModList
     private final List<ModInfo> sortedList;
     private final Map<String, ModFileInfo> fileById;
     private final List<EarlyLoadingException> preLoadErrors;
-    private List<ModFile> brokenFiles;
+    private List<IModFile> brokenFiles;
 
     private LoadingModList(final List<ModFile> modFiles, final List<ModInfo> sortedList)
     {
@@ -168,11 +161,11 @@ public class LoadingModList
         return preLoadErrors;
     }
 
-    public void setBrokenFiles(final List<ModFile> brokenFiles) {
+    public void setBrokenFiles(final List<IModFile> brokenFiles) {
         this.brokenFiles = brokenFiles;
     }
 
-    public List<ModFile> getBrokenFiles() {
+    public List<IModFile> getBrokenFiles() {
         return this.brokenFiles;
     }
 }

fmlloader/src/main/java/net/minecraftforge/fml/loading/LogMarkers.java

@@ -1,30 +1,16 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;
 
-import org.apache.logging.log4j.Marker;
-import org.apache.logging.log4j.MarkerManager;
+import org.slf4j.Marker;
+import org.slf4j.MarkerFactory;
 
 public class LogMarkers {
-    public static final Marker CORE = MarkerManager.getMarker("CORE");
-    public static final Marker LOADING = MarkerManager.getMarker("LOADING");
-    public static final Marker SCAN = MarkerManager.getMarker("SCAN");
-    public static final Marker SPLASH = MarkerManager.getMarker("SPLASH");
+    public static final Marker CORE = MarkerFactory.getMarker("CORE");
+    public static final Marker LOADING = MarkerFactory.getMarker("LOADING");
+    public static final Marker SCAN = MarkerFactory.getMarker("SCAN");
+    public static final Marker SPLASH = MarkerFactory.getMarker("SPLASH");
 }

fmlloader/src/main/java/net/minecraftforge/fml/loading/MCPNamingService.java

@@ -1,9 +1,14 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.fml.loading;
 
+import com.mojang.logging.LogUtils;
 import cpw.mods.modlauncher.api.INameMappingService;
 import org.apache.commons.lang3.tuple.Pair;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import org.slf4j.Logger;
 
 import java.io.BufferedReader;
 import java.io.IOException;
@@ -15,7 +20,7 @@ import java.util.function.BiConsumer;
 import java.util.function.BiFunction;
 
 public class MCPNamingService implements INameMappingService {
-    private static final Logger LOGGER = LogManager.getLogger();
+    private static final Logger LOGGER = LogUtils.getLogger();
     private HashMap<String, String> methods;
     private HashMap<String, String> fields;
 

fmlloader/src/main/java/net/minecraftforge/fml/loading/MavenCoordinateResolver.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;

fmlloader/src/main/java/net/minecraftforge/fml/loading/ModDirTransformerDiscoverer.java

@@ -1,38 +1,33 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;
 
+import com.mojang.logging.LogUtils;
+import cpw.mods.jarhandling.SecureJar;
 import cpw.mods.modlauncher.api.LamdbaExceptionUtils;
 import cpw.mods.modlauncher.api.NamedPath;
 import cpw.mods.modlauncher.serviceapi.ITransformerDiscoveryService;
-import org.apache.logging.log4j.LogManager;
+import org.slf4j.Logger;
 
-import java.io.File;
 import java.io.IOException;
+import java.lang.module.ModuleDescriptor;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.List;
-import java.util.zip.ZipFile;
+import java.util.Set;
 
 public class ModDirTransformerDiscoverer implements ITransformerDiscoveryService {
+    private static final Logger LOGGER = LogUtils.getLogger();
+    private static final Set<String> SERVICES = Set.of(
+        "cpw.mods.modlauncher.api.ITransformationService",
+        "net.minecraftforge.forgespi.locating.IModLocator",
+        "net.minecraftforge.forgespi.locating.IDependencyLocator"
+    );
+
     @Override
     public List<NamedPath> candidates(final Path gameDirectory) {
         ModDirTransformerDiscoverer.scan(gameDirectory);
@@ -54,7 +49,7 @@ public class ModDirTransformerDiscoverer implements ITransformerDiscoveryService
         try (var walk = Files.walk(modsDir, 1)){
             walk.forEach(ModDirTransformerDiscoverer::visitFile);
         } catch (IOException | IllegalStateException ioe) {
-            LogManager.getLogger().error("Error during early discovery", ioe);
+            LOGGER.error("Error during early discovery", ioe);
         }
     }
 
@@ -62,14 +57,11 @@ public class ModDirTransformerDiscoverer implements ITransformerDiscoveryService
         if (!Files.isRegularFile(path)) return;
         if (!path.toString().endsWith(".jar")) return;
         if (LamdbaExceptionUtils.uncheck(() -> Files.size(path)) == 0) return;
-        try (ZipFile zf = new ZipFile(new File(path.toUri()))) {
-            if (zf.getEntry("META-INF/services/cpw.mods.modlauncher.api.ITransformationService") != null) {
-                found.add(new NamedPath(zf.getName(), path));
-            } else if (zf.getEntry("META-INF/services/net.minecraftforge.forgespi.locating.IModLocator") != null) {
-                found.add(new NamedPath(zf.getName(), path));
-            }
-        } catch (IOException ioe) {
-            LogManager.getLogger().error("Zip Error when loading jar file {}", path, ioe);
-        }
+
+        SecureJar jar = SecureJar.from(path);
+        jar.moduleDataProvider().descriptor().provides().stream()
+            .map(ModuleDescriptor.Provides::service)
+            .filter(SERVICES::contains)
+            .forEach(s -> found.add(new NamedPath(s, path)));
     }
 }

fmlloader/src/main/java/net/minecraftforge/fml/loading/ModJarURLHandler.java

@@ -1,27 +1,13 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;
 
+import com.mojang.logging.LogUtils;
 import cpw.mods.modlauncher.api.LamdbaExceptionUtils;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import org.slf4j.Logger;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -38,7 +24,7 @@ import static net.minecraftforge.fml.loading.LogMarkers.CORE;
 
 public class ModJarURLHandler extends URLStreamHandler
 {
-    private static final Logger LOGGER = LogManager.getLogger();
+    private static final Logger LOGGER = LogUtils.getLogger();
     // modjar://modid/path/to/file
     @Override
     protected URLConnection openConnection(URL url) {

fmlloader/src/main/java/net/minecraftforge/fml/loading/ModSorter.java

@@ -1,26 +1,15 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;
 
 import com.google.common.graph.GraphBuilder;
 import com.google.common.graph.MutableGraph;
+import com.mojang.logging.LogUtils;
+import cpw.mods.jarhandling.SecureJar;
+import net.minecraftforge.fml.loading.moddiscovery.MinecraftLocator;
 import net.minecraftforge.forgespi.language.IModFileInfo;
 import net.minecraftforge.forgespi.language.IModInfo;
 import net.minecraftforge.fml.loading.EarlyLoadingException.ExceptionData;
@@ -29,15 +18,14 @@ import net.minecraftforge.fml.loading.moddiscovery.ModFileInfo;
 import net.minecraftforge.fml.loading.moddiscovery.ModInfo;
 import net.minecraftforge.fml.loading.toposort.CyclePresentException;
 import net.minecraftforge.fml.loading.toposort.TopologicalSort;
-import net.minecraftforge.forgespi.locating.IModFile;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
 import org.apache.maven.artifact.versioning.ArtifactVersion;
 import org.apache.maven.artifact.versioning.DefaultArtifactVersion;
+import org.slf4j.Logger;
 
 import java.util.*;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Function;
+import java.util.jar.Manifest;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -46,15 +34,16 @@ import static net.minecraftforge.fml.loading.LogMarkers.LOADING;
 
 public class ModSorter
 {
-    private static final Logger LOGGER = LogManager.getLogger();
+    private static final Logger LOGGER = LogUtils.getLogger();
+    private final UniqueModListBuilder uniqueModListBuilder;
     private List<ModFile> modFiles;
     private List<ModInfo> sortedList;
-    private Map<String, ModInfo> modIdNameLookup;
-    private List<ModFile> forgeAndMC;
+    private Map<String, IModInfo> modIdNameLookup;
+    private List<ModFile> systemMods;
 
     private ModSorter(final List<ModFile> modFiles)
     {
-        this.modFiles = modFiles;
+        this.uniqueModListBuilder = new UniqueModListBuilder(modFiles);
     }
 
     public static LoadingModList sort(List<ModFile> mods, final List<ExceptionData> errors)
@@ -64,13 +53,13 @@ public class ModSorter
             ms.buildUniqueList();
         } catch (EarlyLoadingException e) {
             // We cannot build any list with duped mods. We have to abort immediately and report it
-            return LoadingModList.of(ms.forgeAndMC, ms.forgeAndMC.stream().map(mf->(ModInfo)mf.getModInfos().get(0)).collect(toList()), e);
+            return LoadingModList.of(ms.systemMods, ms.systemMods.stream().map(mf->(ModInfo)mf.getModInfos().get(0)).collect(toList()), e);
         }
         // try and validate dependencies
         final List<ExceptionData> failedList = Stream.concat(ms.verifyDependencyVersions().stream(), errors.stream()).toList();
         // if we miss one or the other, we abort now
         if (!failedList.isEmpty()) {
-            return LoadingModList.of(ms.forgeAndMC, ms.forgeAndMC.stream().map(mf->(ModInfo)mf.getModInfos().get(0)).collect(toList()), new EarlyLoadingException("failure to validate mod list", null, failedList));
+            return LoadingModList.of(ms.systemMods, ms.systemMods.stream().map(mf->(ModInfo)mf.getModInfos().get(0)).collect(toList()), new EarlyLoadingException("failure to validate mod list", null, failedList));
         } else {
             // Otherwise, lets try and sort the modlist and proceed
             EarlyLoadingException earlyLoadingException = null;
@@ -89,11 +78,12 @@ public class ModSorter
         // lambdas are identity based, so sorting them is impossible unless you hold reference to them
         final MutableGraph<ModFileInfo> graph = GraphBuilder.directed().build();
         AtomicInteger counter = new AtomicInteger();
-        Map<IModFileInfo, Integer> infos = modFiles.stream()
+        Map<ModFileInfo, Integer> infos = modFiles.stream()
                 .map(ModFile::getModFileInfo)
                 .filter(ModFileInfo.class::isInstance)
+                .map(ModFileInfo.class::cast)
                 .collect(toMap(Function.identity(), e -> counter.incrementAndGet()));
-        infos.keySet().forEach(i -> graph.addNode((ModFileInfo) i));
+        infos.keySet().forEach(graph::addNode);
         modFiles.stream()
                 .map(ModFile::getModInfos)
                 .<IModInfo>mapMulti(Iterable::forEach)
@@ -109,11 +99,10 @@ public class ModSorter
         catch (CyclePresentException e)
         {
             Set<Set<ModFileInfo>> cycles = e.getCycles();
-            LOGGER.error(LOADING, () -> new AdvancedLogMessageAdapter(buffer ->
-                    buffer.append("Mod Sorting failed.\n")
-                    .append("Detected Cycles: ")
-                    .append(cycles)
-                    .append('\n')));
+            if (LOGGER.isErrorEnabled(LOADING))
+            {
+                LOGGER.error(LOADING, "Mod Sorting failed.\nDetected Cycles: {}\n", cycles);
+            }
             var dataList = cycles.stream()
                     .<ModFileInfo>mapMulti(Iterable::forEach)
                     .<IModInfo>mapMulti((mf,c)->mf.getMods().forEach(c))
@@ -136,10 +125,9 @@ public class ModSorter
     private void addDependency(MutableGraph<ModFileInfo> topoGraph, IModInfo.ModVersion dep)
     {
         final ModFileInfo self = (ModFileInfo)dep.getOwner().getOwningFile();
-        final ModInfo targetModInfo = modIdNameLookup.get(dep.getModId());
+        final IModInfo targetModInfo = modIdNameLookup.get(dep.getModId());
         // soft dep that doesn't exist. Just return. No edge required.
-        if (targetModInfo == null) return;
-        final ModFileInfo target = targetModInfo.getOwningFile();
+        if (targetModInfo == null || !(targetModInfo.getOwningFile() instanceof final ModFileInfo target)) return;
         if (self == target)
             return; // in case a jar has two mods that have dependencies between
         switch (dep.getOrdering()) {
@@ -150,62 +138,49 @@ public class ModSorter
 
     private void buildUniqueList()
     {
-        // Collect mod files by module name. This will be used for deduping purposes
-        final Map<String, List<IModFile>> modFilesByFirstId = modFiles.stream()
-                .collect(groupingBy(mf -> mf.getModFileInfo().moduleName()));
+        final UniqueModListBuilder.UniqueModListData uniqueModListData = uniqueModListBuilder.buildUniqueList();
 
-        // Capture forge and MC here, so we can keep them for later
-        forgeAndMC = new ArrayList<>();
-        var mc = modFilesByFirstId.get("minecraft");
-        if (mc != null && !mc.isEmpty())
-            forgeAndMC.add((ModFile) mc.get(0));
-        else
-            throw new IllegalStateException("Failed to find minecraft somehow?");
-        // TODO: remove this hardcoding and make it more flexible
-        var forge = modFilesByFirstId.get("forge");
-        if (forge != null && !forge.isEmpty())
-            forgeAndMC.add((ModFile) forge.get(0)); // Silently ignore if Forge isn't present
+        this.modFiles = uniqueModListData.modFiles();
 
-        // Select the newest by artifact version sorting of non-unique files thus identified
-        this.modFiles = modFilesByFirstId.entrySet().stream()
-                .map(this::selectNewestModInfo)
-                .map(Map.Entry::getValue)
-                .map(ModFile.class::cast)
-                .collect(toList());
+        detectSystemMods(uniqueModListData.modFilesByFirstId());
 
-        // Transform to the full mod id list
-        final Map<String, List<ModInfo>> modIds = modFiles.stream()
-                .map(ModFile::getModInfos)
-                .flatMap(Collection::stream)
-                .map(ModInfo.class::cast)
-                .collect(groupingBy(IModInfo::getModId));
-
-        // Its theoretically possible that some mod has somehow moved an id to a secondary place, thus causing a dupe.
-        // We can't handle this
-        final List<ModInfo> dupedMods = modIds.values().stream()
-                .filter(modInfos -> modInfos.size() > 1)
-                .map(modInfos -> modInfos.get(0))
-                .toList();
-
-        if (!dupedMods.isEmpty()) {
-            final List<EarlyLoadingException.ExceptionData> duplicateModErrors = dupedMods.stream()
-                    .map(dm -> new EarlyLoadingException.ExceptionData("fml.modloading.dupedmod",
-                            dm, Objects.toString(dm))).toList();
-            throw new EarlyLoadingException("Duplicate mods found", null,  duplicateModErrors);
-        }
-
-        modIdNameLookup = modIds.entrySet().stream()
-                .collect(toMap(Map.Entry::getKey, e -> e.getValue().get(0)));
+        modIdNameLookup = uniqueModListData.modFilesByFirstId().entrySet().stream()
+                .filter(e -> !e.getValue().get(0).getModInfos().isEmpty())
+                .collect(Collectors.toMap(
+                    Map.Entry::getKey,
+                    e -> e.getValue().get(0).getModInfos().get(0)
+                  ));
     }
 
-    private Map.Entry<String, IModFile> selectNewestModInfo(Map.Entry<String, List<IModFile>> fullList) {
-        List<IModFile> modInfoList = fullList.getValue();
-        if (modInfoList.size() > 1) {
-            LOGGER.debug("Found {} mods for first modid {}, selecting most recent based on version data", modInfoList.size(), fullList.getKey());
-            modInfoList.sort(Comparator.<IModFile, ArtifactVersion>comparing(mf -> mf.getModInfos().get(0).getVersion()).reversed());
-            LOGGER.debug("Selected file {} for modid {} with version {}", modInfoList.get(0).getFileName(), fullList.getKey(), modInfoList.get(0).getModInfos().get(0).getVersion());
+    private void detectSystemMods(final Map<String, List<ModFile>> modFilesByFirstId)
+    {
+        // Capture system mods (ex. MC, Forge) here, so we can keep them for later
+        final Set<String> systemMods = new HashSet<>();
+        // The minecraft mod is always a system mod
+        systemMods.add("minecraft");
+        // Find mod file from MinecraftLocator to define the system mods
+        modFiles.stream()
+                .filter(modFile -> modFile.getProvider().getClass() == MinecraftLocator.class)
+                .map(ModFile::getSecureJar)
+                .map(SecureJar::moduleDataProvider)
+                .map(SecureJar.ModuleDataProvider::getManifest)
+                .map(Manifest::getMainAttributes)
+                .map(mf -> mf.getValue("FML-System-Mods"))
+                .filter(Objects::nonNull)
+                .findFirst()
+                .ifPresent(value -> systemMods.addAll(Arrays.asList(value.split(","))));
+        LOGGER.debug("Configured system mods: {}", systemMods);
+
+        this.systemMods = new ArrayList<>();
+        for (String systemMod : systemMods) {
+            var container = modFilesByFirstId.get(systemMod);
+            if (container != null && !container.isEmpty()) {
+                LOGGER.debug("Found system mod: {}", systemMod);
+                this.systemMods.add((ModFile) container.get(0));
+            } else {
+                throw new IllegalStateException("Failed to find system mod: " + systemMod);
+            }
         }
-        return Map.entry(fullList.getKey(), modInfoList.get(0));
     }
 
     private List<EarlyLoadingException.ExceptionData> verifyDependencyVersions()
@@ -235,10 +210,24 @@ public class ModSorter
 
         if (!missingVersions.isEmpty()) {
             if (mandatoryMissing > 0) {
-                LOGGER.error(LOADING, "Missing mandatory dependencies: {}", missingVersions.stream().filter(IModInfo.ModVersion::isMandatory).map(IModInfo.ModVersion::getModId).collect(Collectors.joining(", ")));
+                LOGGER.error(
+                        LOADING,
+                        "Missing or unsupported mandatory dependencies:\n{}",
+                        missingVersions.stream()
+                                .filter(IModInfo.ModVersion::isMandatory)
+                                .map(ver -> formatDependencyError(ver, modVersions))
+                                .collect(Collectors.joining("\n"))
+                );
             }
             if (missingVersions.size() - mandatoryMissing > 0) {
-                LOGGER.error(LOADING, "Unsupported installed optional dependencies: {}", missingVersions.stream().filter(ver -> !ver.isMandatory()).map(IModInfo.ModVersion::getModId).collect(Collectors.joining(", ")));
+                LOGGER.error(
+                        LOADING,
+                        "Unsupported installed optional dependencies:\n{}",
+                        missingVersions.stream()
+                                .filter(ver -> !ver.isMandatory())
+                                .map(ver -> formatDependencyError(ver, modVersions))
+                                .collect(Collectors.joining("\n"))
+                );
             }
 
             return missingVersions.stream()
@@ -250,6 +239,18 @@ public class ModSorter
         return Collections.emptyList();
     }
 
+    private static String formatDependencyError(IModInfo.ModVersion dependency, Map<String, ArtifactVersion> modVersions)
+    {
+        ArtifactVersion installed = modVersions.get(dependency.getModId());
+        return String.format(
+                "\tMod ID: '%s', Requested by: '%s', Expected range: '%s', Actual version: '%s'",
+                dependency.getModId(),
+                dependency.getOwner().getModId(),
+                dependency.getVersionRange(),
+                installed != null ? installed.toString() : "[MISSING]"
+        );
+    }
+
     private boolean modVersionNotContained(final IModInfo.ModVersion mv, final Map<String, ArtifactVersion> modVersions)
     {
         return !(VersionSupportMatrix.testVersionSupportMatrix(mv.getVersionRange(), mv.getModId(), "mod", (modId, range) -> modVersions.containsKey(modId) &&

fmlloader/src/main/java/net/minecraftforge/fml/loading/RuntimeDistCleaner.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;
@@ -30,14 +16,11 @@ import java.util.function.Consumer;
 import java.util.stream.Collectors;
 
 import com.google.common.collect.Streams;
+import com.mojang.logging.LogUtils;
 import cpw.mods.modlauncher.serviceapi.ILaunchPluginService;
 import net.minecraftforge.api.distmarker.Dist;
 import net.minecraftforge.api.distmarker.OnlyIn;
 import net.minecraftforge.api.distmarker.OnlyIns;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
-import org.apache.logging.log4j.Marker;
-import org.apache.logging.log4j.MarkerManager;
 import org.objectweb.asm.Handle;
 import org.objectweb.asm.MethodVisitor;
 import org.objectweb.asm.Opcodes;
@@ -47,11 +30,14 @@ import org.objectweb.asm.tree.AnnotationNode;
 import org.objectweb.asm.tree.ClassNode;
 import org.objectweb.asm.tree.FieldNode;
 import org.objectweb.asm.tree.MethodNode;
+import org.slf4j.Logger;
+import org.slf4j.Marker;
+import org.slf4j.MarkerFactory;
 
 public class RuntimeDistCleaner implements ILaunchPluginService
 {
-    private static final Logger LOGGER = LogManager.getLogger();
-    private static final Marker DISTXFORM = MarkerManager.getMarker("DISTXFORM");
+    private static final Logger LOGGER = LogUtils.getLogger();
+    private static final Marker DISTXFORM = MarkerFactory.getMarker("DISTXFORM");
     private static String DIST;
     private static final String ONLYIN = Type.getDescriptor(OnlyIn.class);
     private static final String ONLYINS = Type.getDescriptor(OnlyIns.class);
@@ -67,7 +53,7 @@ public class RuntimeDistCleaner implements ILaunchPluginService
         AtomicBoolean changes = new AtomicBoolean();
         if (remove(classNode.visibleAnnotations, DIST))
         {
-            LOGGER.fatal(DISTXFORM, "Attempted to load class {} for invalid dist {}", classNode.name, DIST);
+            LOGGER.error(DISTXFORM, "Attempted to load class {} for invalid dist {}", classNode.name, DIST);
             throw new RuntimeException("Attempted to load class "+ classNode.name  + " for invalid dist "+ DIST);
         }
 

fmlloader/src/main/java/net/minecraftforge/fml/loading/StringSubstitutor.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;

fmlloader/src/main/java/net/minecraftforge/fml/loading/StringUtils.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;

fmlloader/src/main/java/net/minecraftforge/fml/loading/TracingPrintStream.java

@@ -1,26 +1,11 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;
 
-import org.apache.logging.log4j.Logger;
-
+import org.slf4j.Logger;
 import java.io.PrintStream;
 
 /**

fmlloader/src/main/java/net/minecraftforge/fml/loading/UniqueModListBuilder.java

@@ -0,0 +1,133 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.minecraftforge.fml.loading;
+
+import com.mojang.logging.LogUtils;
+import net.minecraftforge.fml.loading.moddiscovery.ModFile;
+import net.minecraftforge.forgespi.language.IModInfo;
+import org.apache.maven.artifact.versioning.ArtifactVersion;
+import org.slf4j.Logger;
+
+import java.util.*;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+import static java.util.stream.Collectors.*;
+
+public class UniqueModListBuilder
+{
+    private final static Logger LOGGER = LogUtils.getLogger();
+
+    private final List<ModFile> modFiles;
+
+    public UniqueModListBuilder(final List<ModFile> modFiles) {this.modFiles = modFiles;}
+
+    public UniqueModListData buildUniqueList()
+    {
+        List<ModFile> uniqueModList;
+        List<ModFile> uniqueLibListWithVersion;
+
+        // Collect mod files by module name. This will be used for deduping purposes
+        final Map<String, List<ModFile>> modFilesByFirstId = modFiles.stream()
+                .filter(mf -> mf.getModFileInfo() != null)
+                .collect(groupingBy(UniqueModListBuilder::getModId));
+
+        final Map<String, List<ModFile>> libFilesWithVersionByModuleName = modFiles.stream()
+                .filter(mf -> mf.getModFileInfo() == null)
+                .collect(groupingBy(UniqueModListBuilder::getModId));
+
+        // Select the newest by artifact version sorting of non-unique files thus identified
+        uniqueModList = modFilesByFirstId.entrySet().stream()
+                .map(this::selectNewestModInfo)
+                .toList();
+
+        // Select the newest by artifact version sorting of non-unique files thus identified
+        uniqueLibListWithVersion = libFilesWithVersionByModuleName.entrySet().stream()
+                .map(this::selectNewestModInfo)
+                .toList();
+
+        // Transform to the full mod id list
+        final Map<String, List<IModInfo>> modIds = uniqueModList.stream()
+                .filter(mf -> mf.getModFileInfo() != null) //Filter out non-mod files, we don't care about those for now.....
+                .map(ModFile::getModInfos)
+                .flatMap(Collection::stream)
+                .collect(groupingBy(IModInfo::getModId));
+
+        // Transform to the full lib id list
+        final Map<String, List<ModFile>> versionedLibIds = uniqueLibListWithVersion.stream()
+                .map(UniqueModListBuilder::getModId)
+                .collect(Collectors.toMap(
+                    Function.identity(),
+                    libFilesWithVersionByModuleName::get
+                ));
+
+        // Its theoretically possible that some mod has somehow moved an id to a secondary place, thus causing a dupe.
+        // We can't handle this
+        final List<IModInfo> dupedMods = modIds.values().stream()
+                .filter(modInfos -> modInfos.size() > 1)
+                .map(modInfos -> modInfos.get(0))
+                .toList();
+
+        if (!dupedMods.isEmpty()) {
+            final List<EarlyLoadingException.ExceptionData> duplicateModErrors = dupedMods.stream()
+                                                                                   .map(dm -> new EarlyLoadingException.ExceptionData("fml.modloading.dupedmod", dm, Objects.toString(dm)))
+                                                                                   .toList();
+            throw new EarlyLoadingException("Duplicate mods found", null,  duplicateModErrors);
+        }
+
+        final List<ModFile> dupedLibs = versionedLibIds.values().stream()
+                .filter(modFiles -> modFiles.size() > 1)
+                .map(modFiles -> modFiles.get(0))
+                .toList();
+
+        if (!dupedLibs.isEmpty()) {
+            final List<EarlyLoadingException.ExceptionData> duplicateLibErrors = dupedLibs.stream()
+                .map(dm -> new EarlyLoadingException.ExceptionData("fml.modloading.dupedlib.versioned", dm, Objects.toString(dm)))
+                .toList();
+            throw new EarlyLoadingException("Duplicate plugins or libraries found", null,  duplicateLibErrors);
+        }
+
+        // Collect unique mod files by module name. This will be used for deduping purposes
+        final Map<String, List<ModFile>> uniqueModFilesByFirstId = uniqueModList.stream()
+                .collect(groupingBy(UniqueModListBuilder::getModId));
+
+        final List<ModFile> loadedList = new ArrayList<>();
+        loadedList.addAll(uniqueModList);
+        loadedList.addAll(uniqueLibListWithVersion);
+
+        return new UniqueModListData(loadedList, uniqueModFilesByFirstId);
+    }
+
+    private ModFile selectNewestModInfo(Map.Entry<String, List<ModFile>> fullList) {
+        List<ModFile> modInfoList = fullList.getValue();
+        if (modInfoList.size() > 1) {
+            LOGGER.debug("Found {} mods for first modid {}, selecting most recent based on version data", modInfoList.size(), fullList.getKey());
+            modInfoList.sort(Comparator.comparing(this::getVersion).reversed());
+            LOGGER.debug("Selected file {} for modid {} with version {}", modInfoList.get(0).getFileName(), fullList.getKey(), this.getVersion(modInfoList.get(0)));
+        }
+        return modInfoList.get(0);
+    }
+
+    private ArtifactVersion getVersion(final ModFile mf)
+    {
+        if (mf.getModFileInfo() == null || mf.getModInfos() == null || mf.getModInfos().isEmpty()) {
+            return mf.getJarVersion();
+        }
+
+        return mf.getModInfos().get(0).getVersion();
+    }
+
+    private static String getModId(ModFile modFile) {
+        if (modFile.getModFileInfo() == null || modFile.getModFileInfo().getMods().isEmpty()) {
+            return modFile.getSecureJar().name();
+        }
+
+        return modFile.getModFileInfo().moduleName();
+    }
+
+    public record UniqueModListData(List<ModFile> modFiles, Map<String, List<ModFile>> modFilesByFirstId) {}
+
+}

fmlloader/src/main/java/net/minecraftforge/fml/loading/VersionInfo.java

@@ -1,3 +1,8 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.fml.loading;
 
 import java.util.Map;

fmlloader/src/main/java/net/minecraftforge/fml/loading/VersionSupportMatrix.java

@@ -1,24 +1,11 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading;
 
+import net.minecraftforge.forgespi.language.MavenVersionAdapter;
 import org.apache.maven.artifact.versioning.ArtifactVersion;
 import org.apache.maven.artifact.versioning.DefaultArtifactVersion;
 import org.apache.maven.artifact.versioning.VersionRange;
@@ -32,16 +19,12 @@ public class VersionSupportMatrix {
     private static final HashMap<String, List<ArtifactVersion>> overrideVersions = new HashMap<>();
     static {
         final ArtifactVersion version = new DefaultArtifactVersion(FMLLoader.versionInfo().mcVersion());
-        // if (MavenVersionAdapter.createFromVersionSpec("[1.16.4,1.16.5]").containsVersion(version)) {
-        //     // 1.16.4 is Compatible with 1.16.3
-        //     add("languageloader.javafml", "34");
-        //     add("mod.minecraft",          "1.16.3");
-        //     add("mod.forge",              "34.1.42");
-        //     // 1.16.5 is Compatible with 1.16.4, and thus 1.16.3
-        //     add("languageloader.javafml", "35");
-        //     add("mod.minecraft",          "1.16.4");
-        //     add("mod.forge",              "35.1.37");
-        // }
+         if (MavenVersionAdapter.createFromVersionSpec("[1.19.2]").containsVersion(version)) {
+             // 1.19.2 is Compatible with 1.19.1
+             add("languageloader.javafml", "42");
+             add("mod.minecraft",          "1.19.1");
+             add("mod.forge",              "42.0.9");
+        }
     }
     private static void add(String key, String value) {
         overrideVersions.computeIfAbsent(key, k -> new ArrayList<>()).add(new DefaultArtifactVersion(value));

fmlloader/src/main/java/net/minecraftforge/fml/loading/log4j/ForgeHighlight.java

@@ -1,20 +1,6 @@
 /*
- * Minecraft Forge
- * Copyright (c) 2016-2021.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
  */
 
 package net.minecraftforge.fml.loading.log4j;

fmlloader/src/main/java/net/minecraftforge/fml/loading/log4j/SLF4JFixerLaunchPluginService.java

@@ -1,3 +1,8 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.fml.loading.log4j;
 
 import cpw.mods.modlauncher.api.NamedPath;

fmlloader/src/main/java/net/minecraftforge/fml/loading/moddiscovery/AbstractJarFileDependencyLocator.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.minecraftforge.fml.loading.moddiscovery;
+
+import com.mojang.logging.LogUtils;
+import net.minecraftforge.forgespi.locating.IDependencyLocator;
+import net.minecraftforge.forgespi.locating.IModFile;
+import net.minecraftforge.forgespi.locating.ModFileLoadingException;
+import org.slf4j.Logger;
+
+import java.io.FileNotFoundException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Optional;
+
+public abstract class AbstractJarFileDependencyLocator extends AbstractJarFileModProvider implements IDependencyLocator
+{
+    private static final Logger LOGGER = LogUtils.getLogger();
+
+    protected Optional<InputStream> loadResourceFromModFile(final IModFile modFile, final Path path) {
+        try {
+            return Optional.of(Files.newInputStream(modFile.findResource(path.toString())));
+        }
+        catch (final FileNotFoundException e) {
+            LOGGER.debug("Failed to load resource {} from {}, it does not contain dependency information.", path, modFile.getFileName());
+            return Optional.empty();
+        }
+        catch (final Exception e) {
+            LOGGER.error("Failed to load resource {} from mod {}, cause {}", path, modFile.getFileName(), e);
+            return Optional.empty();
+        }
+    }
+
+    protected Optional<IModFile> loadModFileFrom(final IModFile file, final Path path) {
+        try {
+            final Path pathInModFile = file.findResource(path.toString());
+            return Optional.of(createMod(pathInModFile).file());
+        }
+        catch (Exception e) {
+            LOGGER.error("Failed to load mod file {} from {}", path, file.getFileName());
+            throw new ModFileLoadingException("Failed to load mod file "+file.getFileName());
+        }
+    }
+
+    protected String identifyMod(final IModFile modFile) {
+        return modFile.getFileName();
+    }
+}

fmlloader/src/main/java/net/minecraftforge/fml/loading/moddiscovery/AbstractJarFileLocator.java

@@ -1,71 +0,0 @@
-/*
- * Minecraft Forge
- * Copyright (c) 2016-2022.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
- */
-
-package net.minecraftforge.fml.loading.moddiscovery;
-
-import cpw.mods.jarhandling.SecureJar;
-import cpw.mods.jarhandling.JarMetadata;
-import net.minecraftforge.fml.loading.LogMarkers;
-import net.minecraftforge.forgespi.language.IConfigurable;
-import net.minecraftforge.forgespi.language.IModFileInfo;
-import net.minecraftforge.forgespi.language.IModInfo;
-import net.minecraftforge.forgespi.locating.IModFile;
-import net.minecraftforge.forgespi.locating.IModLocator;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
-
-import java.io.IOException;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.util.Collections;
-import java.util.List;
-import java.util.Map;
-import java.util.Optional;
-import java.util.function.Consumer;
-import java.util.function.Function;
-import java.util.jar.Manifest;
-import java.util.stream.Collectors;
-import java.util.stream.Stream;
-
-public abstract class AbstractJarFileLocator extends AbstractModLocator {
-    private static final Logger LOGGER = LogManager.getLogger();
-
-    @Override
-    public void scanFile(final IModFile file, final Consumer<Path> pathConsumer) {
-        LOGGER.debug(LogMarkers.SCAN,"Scan started: {}", file);
-        final Function<Path, SecureJar.Status> status = p->file.getSecureJar().verifyPath(p);
-        try (Stream<Path> files = Files.find(file.getSecureJar().getRootPath(), Integer.MAX_VALUE, (p, a) -> p.getNameCount() > 0 && p.getFileName().toString().endsWith(".class"))) {
-            file.setSecurityStatus(files.peek(pathConsumer).map(status).reduce((s1, s2)-> SecureJar.Status.values()[Math.min(s1.ordinal(), s2.ordinal())]).orElse(SecureJar.Status.INVALID));
-        } catch (IOException e) {
-            e.printStackTrace();
-        }
-        LOGGER.debug(LogMarkers.SCAN,"Scan finished: {}", file);
-    }
-
-    @Override
-    public List<IModFile> scanMods() {
-        return scanCandidates()
-                .map(this::createMod)
-                .filter(Optional::isPresent)
-                .map(Optional::get)
-                .collect(Collectors.toList());
-    }
-
-    public abstract Stream<Path> scanCandidates();
-}

fmlloader/src/main/java/net/minecraftforge/fml/loading/moddiscovery/AbstractJarFileModLocator.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.minecraftforge.fml.loading.moddiscovery;
+
+import net.minecraftforge.forgespi.locating.IModLocator;
+
+import java.nio.file.Path;
+import java.util.List;
+import java.util.stream.Stream;
+
+public abstract class AbstractJarFileModLocator extends AbstractJarFileModProvider implements IModLocator
+{
+    @Override
+    public List<IModLocator.ModFileOrException> scanMods()
+    {
+        return scanCandidates().map(this::createMod).toList();
+    }
+
+    public abstract Stream<Path> scanCandidates();
+}

fmlloader/src/main/java/net/minecraftforge/fml/loading/moddiscovery/AbstractJarFileModProvider.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.minecraftforge.fml.loading.moddiscovery;
+
+import com.mojang.logging.LogUtils;
+import cpw.mods.jarhandling.SecureJar;
+import net.minecraftforge.fml.loading.LogMarkers;
+import net.minecraftforge.forgespi.locating.IModFile;
+import org.slf4j.Logger;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.stream.Stream;
+
+public abstract class AbstractJarFileModProvider extends AbstractModProvider
+{
+    private static final Logger LOGGER = LogUtils.getLogger();
+
+    @Override
+    public void scanFile(final IModFile file, final Consumer<Path> pathConsumer) {
+        LOGGER.debug(LogMarkers.SCAN,"Scan started: {}", file);
+        final Function<Path, SecureJar.Status> status = p->file.getSecureJar().verifyPath(p);
+        try (Stream<Path> files = Files.find(file.getSecureJar().getRootPath(), Integer.MAX_VALUE, (p, a) -> p.getNameCount() > 0 && p.getFileName().toString().endsWith(".class"))) {
+            file.setSecurityStatus(files.peek(pathConsumer).map(status).reduce((s1, s2)-> SecureJar.Status.values()[Math.min(s1.ordinal(), s2.ordinal())]).orElse(SecureJar.Status.INVALID));
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        LOGGER.debug(LogMarkers.SCAN,"Scan finished: {}", file);
+    }
+}