Migrate to Github Actions

https://forums.minecraftforge.net/topic/154385-forge-435-minecraft-1192/

.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/publish.yml

@@ -0,0 +1,28 @@
+name: Publish
+
+on:
+  push:
+    branches: [ '1.19.2' ]
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    uses: MinecraftForge/SharedActions/.github/workflows/gradle.yml@main
+    with:
+      java: 17
+      gradle_setup: './gradlew setup'
+      gradle_tasks: 'build publish'
+      artifact_name: 'forge'
+    secrets:
+      DISCORD_WEBHOOK: ${{ secrets.DISCORD_WEBHOOK }}
+      PROMOTE_ARTIFACT_WEBHOOK: ${{ secrets.PROMOTE_ARTIFACT_WEBHOOK }}
+      PROMOTE_ARTIFACT_USERNAME: ${{ secrets.PROMOTE_ARTIFACT_USERNAME }}
+      PROMOTE_ARTIFACT_PASSWORD: ${{ secrets.PROMOTE_ARTIFACT_PASSWORD }}
+      MAVEN_USER: ${{ secrets.MAVEN_USER }}
+      MAVEN_PASSWORD: ${{ secrets.MAVEN_PASSWORD }}
+      SIGN_KEY_ALIAS: ${{ secrets.SIGN_KEY_ALIAS }}
+      SIGN_KEY_PASSWORD: ${{ secrets.SIGN_KEY_PASSWORD }}
+      SIGN_KEYSTORE_PASSWORD: ${{ secrets.SIGN_KEYSTORE_PASSWORD }}
+      SIGN_KEYSTORE_DATA: ${{ secrets.SIGN_KEYSTORE_DATA }}

.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-/

Jenkinsfile

@@ -1,125 +0,0 @@
-@Library('forge-shared-library')_
-
-pipeline {
-    options {
-        disableConcurrentBuilds()
-    }
-    agent {
-        docker {
-            image 'gradle:7-jdk16'
-            //args '-v forgegc:/home/gradle/.gradle_cache/'
-        }
-    }
-    environment {
-        GRADLE_ARGS = '--no-daemon --console=plain' // No daemon for now as FG3 kinda derps. //'-Dorg.gradle.daemon.idletimeout=5000'
-        DISCORD_WEBHOOK = credentials('forge-discord-jenkins-webhook')
-        DISCORD_PREFIX = "Job: Forge Branch: ${BRANCH_NAME} Build: #${BUILD_NUMBER}"
-        JENKINS_HEAD = 'https://wiki.jenkins-ci.org/download/attachments/2916393/headshot.png'
-    }
-
-    stages {
-        stage('notify_start') {
-            when {
-                not {
-                    changeRequest()
-                }
-            }
-            steps {
-                discordSend(
-                    title: "${DISCORD_PREFIX} Started",
-                    successful: true,
-                    result: 'ABORTED', //White border
-                    thumbnail: JENKINS_HEAD,
-                    webhookURL: DISCORD_WEBHOOK
-                )
-            }
-        }
-        /*
-        stage('pull_cache') {
-            steps {
-                sh 'cp -r /home/gradle/.gradle_cache/jdks/ /home/gradle/.gradle/jdks/'
-                sh 'cp -r /home/gradle/.gradle_cache/wrapper/ /home/gradle/.gradle/wrapper/'
-                sh 'cp -r /home/gradle/.gradle_cache/caches/ /home/gradle/.gradle/caches/'
-            }
-        }
-        */
-        stage('setup') {
-            steps {
-                withGradle {
-                    sh './gradlew ${GRADLE_ARGS} --refresh-dependencies --continue setup'
-                }
-                script {
-                    env.MYVERSION = sh(returnStdout: true, script: './gradlew :forge:properties -q | grep "^version:" | cut -d" " -f2').trim()
-                    env.FMLONLY_VERSION = sh(returnStdout: true, script: './gradlew :fmlonly:properties -q | grep "^version:" | cut -d" " -f2').trim()
-                }
-            }
-        }
-        stage('changelog') {
-            when {
-                not {
-                    changeRequest()
-                }
-            }
-            steps {
-                writeChangelog(currentBuild, 'build/changelog.txt')
-            }
-        }
-        stage('publish') {
-            when {
-                not {
-                    changeRequest()
-                }
-            }
-            environment {
-                CROWDIN = credentials('forge-crowdin')
-                KEYSTORE = credentials('forge-jenkins-keystore-old')
-                KEYSTORE_KEYPASS = credentials('forge-jenkins-keystore-old-keypass')
-                KEYSTORE_STOREPASS = credentials('forge-jenkins-keystore-old-keypass')
-            }
-            steps {
-                withCredentials([usernamePassword(credentialsId: 'maven-forge-user', usernameVariable: 'MAVEN_USER', passwordVariable: 'MAVEN_PASSWORD')]) {
-                    withGradle {
-                        sh './gradlew ${GRADLE_ARGS} publish -PkeystoreKeyPass=${KEYSTORE_KEYPASS} -PkeystoreStorePass=${KEYSTORE_STOREPASS} -Pkeystore=${KEYSTORE} -PcrowdinKey=${CROWDIN}'
-                    }
-                }
-            }
-            post {
-                success {
-                    build job: 'filegenerator', parameters: [string(name: 'COMMAND', value: "promote net.minecraftforge:forge ${env.MYVERSION} latest")], propagate: false, wait: false
-                    build job: 'filegenerator', parameters: [string(name: 'COMMAND', value: "promote net.minecraftforge:fmlonly ${env.FMLONLY_VERSION} latest")], propagate: false, wait: false
-                }
-            }
-        }
-        stage('test_publish_pr') { //Publish to local repo to test full process, but don't include credentials so it can't sign/publish to maven
-            when {
-                changeRequest()
-            }
-            environment {
-                CROWDIN = credentials('forge-crowdin')
-            }
-            steps {
-                withGradle {
-                    sh './gradlew ${GRADLE_ARGS} publish -PcrowdinKey=${CROWDIN}'
-                }
-            }
-        }
-    }
-    post {
-        always {
-            script {
-                archiveArtifacts artifacts: 'projects/forge/build/libs/**/*.*', fingerprint: true, onlyIfSuccessful: true, allowEmptyArchive: true
-
-                if (env.CHANGE_ID == null) { // This is unset for non-PRs
-                    discordSend(
-                        title: "${DISCORD_PREFIX} Finished ${currentBuild.currentResult}",
-                        description: '```\n' + getChanges(currentBuild) + '\n```',
-                        successful: currentBuild.resultIsBetterOrEqualTo("SUCCESS"),
-                        result: currentBuild.currentResult,
-                        thumbnail: JENKINS_HEAD,
-                        webhookURL: DISCORD_WEBHOOK
-                    )
-                }
-            }
-        }
-    }
-}

LICENSE-header.txt

@@ -1,16 +1,2 @@
-Minecraft Forge
-Copyright (c) 2016-${year}.
-
-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

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 'net.minecraftforge:srgutils:0.4.+'
+    implementation 'org.ow2.asm:asm:9.5'
+    implementation 'org.ow2.asm:asm-tree:9.5'
+    implementation 'net.minecraftforge:srgutils:0.5.+'
+    implementation 'commons-io:commons-io:2.12.0'
 }

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

@@ -4,7 +4,7 @@ import groovy.json.JsonBuilder
 import org.gradle.api.DefaultTask
 import org.gradle.api.file.RegularFileProperty
 import org.gradle.api.tasks.InputFile
-import org.gradle.api.tasks.OutputFile
+import org.gradle.api.tasks.Internal
 import org.gradle.api.tasks.TaskAction
 import org.objectweb.asm.ClassReader
 import org.objectweb.asm.Opcodes
@@ -17,7 +17,9 @@ import java.util.zip.ZipInputStream
 
 abstract class BytecodeFinder extends DefaultTask {
     @InputFile abstract RegularFileProperty getJar()
-    @OutputFile abstract RegularFileProperty getOutput()
+    // It should be fine to mark the output as internal as we want to control when we run it anyways.
+    // This also shuts Gradle 8 up about implicit task dependencies.
+    @Internal abstract RegularFileProperty getOutput()
 
     BytecodeFinder() {
         output.convention(project.layout.buildDirectory.dir(name).map { it.file("output.json") })

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 +1,57 @@
+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
+        }
+        outputs.upToDateWhen { false } // Never up to date, because this setup task should always run
+
+        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.provider {
+                fmlLibs.resolvedConfiguration.lenientConfiguration.files
+            })
+        }
+
+        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

@@ -1,5 +1,6 @@
 package net.minecraftforge.forge.tasks
 
+import groovy.json.JsonBuilder
 import groovy.json.JsonSlurper
 
 import java.io.File
@@ -16,15 +17,18 @@ 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
@@ -37,7 +41,7 @@ public class Util {
             return lst
         }
 	}
-	
+
 	public static String[] getClasspath(project, libs, artifact) {
 		def ret = []
 		artifactTree(project, artifact).each { key, lib ->
@@ -47,7 +51,7 @@ public class Util {
 		}
 		return ret
 	}
-	
+
 	public static def getArtifacts(project, config, classifiers) {
 		def ret = [:]
 		config.resolvedConfiguration.resolvedArtifacts.each {
@@ -70,14 +74,6 @@ public class Util {
 			if (!checkExists(url)) {
 				url = "https://maven.minecraftforge.net/${path}"
 			}
-			//TODO remove when Mojang launcher is updated
-			if (!classifiers && art.classifier != null) { 
-				//Mojang launcher doesn't currently support classifiers, so... move it to part of the version, and force the extension to 'jar'
-				// However, keep the path normal so that our mirror system works.
-				art.version = "${art.version}-${art.classifier}"
-				art.classifier = null
-				art.extension = 'jar'
-			}
 			ret[key] = [
 				name: "${art.group}:${art.name}:${art.version}" + (art.classifier == null ? '' : ":${art.classifier}") + (art.extension == 'jar' ? '' : "@${art.extension}"),
 				downloads: [
@@ -92,14 +88,14 @@ 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}:${task.project.version}" + (classifier == '' ? '' : ':' + classifier)
     }
@@ -123,7 +119,7 @@ public class Util {
 		def files = cfg.resolve()
 		return getArtifacts(project, cfg, true)
 	}
-	
+
 	private static boolean checkExists(url) {
 		try {
 			def code = new URL(url).openConnection().with {
@@ -138,4 +134,9 @@ public class Util {
 			throw e
 		}
 	}
+
+    public static String getLatestForgeVersion(mcVersion) {
+        def json = new JsonSlurper().parseText(new URL("https://files.minecraftforge.net/net/minecraftforge/forge/promotions_slim.json").getText("UTF-8"))
+        return json.promos["$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/EnergySystems.md

@@ -1,9 +0,0 @@
-# On the Contribution of an RF-lite Energy System: "Energy"
-Forge has acquired an Energy system, after many years of debate on the topic. The prevalence of the RF API has warranted the inclusion of a similar (but simpler) implementation to forge for 1.10.2 and onwards.
-Those who wish to use an RF like API, feel free to use it. If you don't want to think about Energy, but know you need it, you can use it *if you wish*. If you want to interoperate with other energy systems, feel free to use this to broker with them.
-
-# On Diversity in Energy Systems
-Forge has always supported diversity in energy-like systems. If you have a burning desire to simulate electricity flow in all it's glory, we fully support you and look forward to playing your mod. If you wish to have pneumatic power, we have no objections, and would love to see your wonderful creations. If you have a power system of your own devising that is simply beyond our imagination, please, blow us away.
-
-# On Modder Obligations
-As a modder, you are under *no* obligation to use or support the forge Energy system. If anyone, user, mod-pack maker or even us, tells you otherwise, refer them to this statement. The Forge energy system is not intended to supplant diversity in energy systems. It is not intended to be one-size-fits-all. The choice to support it, is the choice of the modder.

docs/NewFML.md

@@ -1,127 +0,0 @@
-# FML
-
-Entrypoint : ```FMLServiceProvider.onLoad```
-
-- Verify environment
--- Check all libraries are present: ```accesstransformer```, ```coremod```, ```deobfuscator```
--- Check versions are suitable: ```modlauncher```, ```accesstransformer```, ```coremod```, ```deobfuscator```
-- Find deobfuscated and patched MC
--- If not found, trigger job to generate that (loaded later at FMLLaunchProvider.launch)
-
-Injected arguments:
-
-- ```mods``` : CSV list of mod files to load
-- ```modlist``` : JSON formatted list of mod files in a maven-like repository format
-
-Entrypoint : ```FMLServiceProvider.initializer```
-- Setup paths
--- ```mods``` folder
--- ```config``` folder
-- FML config file read (JSON?)
-- Trigger initial loading
-
-Entrypoint : ```FMLLaunchProvider.launch```
-- Launches the patched and deobfuscated game
-- - If that wasn't found it'll be generated from the vanilla jar and patch/deobf files (see above)
-- Possible we'll use an alternative launch for the development environment
-
-(A goal is that we pre-generate this JAR during forge installation or modpack installation)
-
-## Loading
-
-- First we discover all mods
-- - IModLocator instances present in system are found and queried to compile a master list of all mod artifacts of the three types
-- LANGPROVIDERs are added to the supported language system : IModLanguageProvider
-- The MODS from the list have their META-INF/mods.json file queried for mod instances to load
-- - MODS are cross-referenced for their language being available
-- - MODS are cross-referenced for their libraries being available
-- - MODS are cross-referenced for their MOD dependencies being available
-- - MODS with META-INF/coremods.json specification are loaded into the COREMOD system
-- - MODS with META-INF/accesstransformer.json are loaded into the ACCESSTRANSFORMER system
-- - MODS are enqueued to the background loading system
-- FMLLaunchProvider will be triggered from the ModLauncher to start the game
-
-## Game loading
-
-- Events triggered from loadGame will launch various phases of modloading as before
--- Deprecation of old "FML" events in favour of Forge events
--- If a mod hasn't completed scanning there might be a pause waiting for it to complete before loading (testing indicates this should be a very rare occurrence and isn't worse than existing status quo where all scanning and loading is on-thread)
-
-### ```IModLocator```
-
-Finds mods from various sources of various types
-manifest is queried for type: FMLModType
-
-- MOD : this file will be scanned as a mod. This is default if nothing is present
-- LIBRARY : this file will be added to the classpath and no further processing is done
-- LANGPROVIDER : this file will be loaded as a language provider
-
-#### ```ModsFolderLocator```
-
-- scans for jar files from mods folder
--- able to load all types
--- loads in all environments
--- maybe able to do runtime name transformation for dev time?
-
-Standard mechanism to find and load mods
-
-#### ```ExplodedDirectoryLocator```
-
-- loads a directory as a mod
--- only able to load mods
--- should only load in dev env
-
-Intended as a mechanism to allow development of mods easily by pointing at a compiled output directory
-
-#### ```ArgumentModsLocator``` : NYI
-
-- loads mods from the arguments on the command line
--- able to load all types
--- loads in all environments
-
-### ```IModLanguageProvider```
-
-Provides mod and language provider services
-
-- Provides a means to transform a Mod File (from the IModLocator) into a list of modcontainer objects based on mods.json
-- Scanning work will be done in background threads
-- Language providers can be provided as JARs via the modlocator for ease of distribution
-
-#### ```FMLModLanguageProvider```
-
-This is the standard Java @Mod implementation provider
-
-- provided by default (always supported)
-- All scanning for @Mod will be done in the background thread
-
-#### ```ScalaModLanguageProvider```
-
-This is the scala language provider. It'll be provided separately as a JAR mod download.
-
-- API contract will need definition
-
-Other languages? Kotlin? Alternative Scala versions? Javascript?
-
-## Coremods
-
-Coremods are now forcefully separated into _injection_ and _runtime_ phases.
-
-### Injection
-
-Injection is the act of intercepting the loading of a class and modifying the inbound class with alterations such as additions, replacements and deletions
-
-Injections will be written using Javascript. Two functions are required: a function providing the list of injection sites, and the function to transform the injection site.
-
-All injection sites will need to be pre-specified by the coremod in their metadata. Lookup services should be provided in the Javascript API.
-
-Javascript API for common coremod injection tasks needs to be developed, to allow common best-practice tooling for these complex tasks.
-
-Runtime coremod code (code that has been injected) is Java as usual.
-
-## Background loading thread
-
-Early in loading, a background thread is triggered which will perform scanning tasks for common resources, such as @Mod instances and other annotations. This thread will also be responsible for loading any cached resources, either those defined at build time or pre-computed from previous runs. It may also be tasked with writing those precomputed resources.
-
-There will be a IPreLoaderJobProvider that will allow extension of the scope of these tasks
-
-

docs/README.md

@@ -2,25 +2,21 @@
 
 MinecraftForge
 =============
-[![Stable Release](https://img.shields.io/badge/dynamic/json?url=https://files.minecraftforge.net/net/minecraftforge/forge/promotions_slim.json&label=Stable&prefix=1.17.1-&query=$.promos["1.17.1-recommended"]&color=brightgreen&logo=data:image/svg+xml;base64,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)](https://files.minecraftforge.net)
-[![Latest Release](https://img.shields.io/badge/dynamic/json?url=https://files.minecraftforge.net/net/minecraftforge/forge/promotions_slim.json&label=Latest&prefix=1.17.1-&query=$.promos["1.17.1-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)
+[![Stable Release](https://img.shields.io/badge/dynamic/json?url=https://files.minecraftforge.net/net/minecraftforge/forge/promotions_slim.json&label=Stable&prefix=1.19.2-&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)][Discord] [![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    |
-| ------------- | ------------- |
-|    1.17.x     |    Active     |
-|    1.16.x     |    LTS        |
+| Version      | Support                     |
+|--------------|-----------------------------|
+| All versions | [Supported][Support-Policy] |
 
 * [Download]
 * [Forum]
 * [Discord]
 * [Documentation]
 
-#### Notes:
-- Introduced in 1.13 was a new FML, information found [here](NewFML.md).
-
 # Installing Forge
 
 Go to [the Forge website](https://files.minecraftforge.net)
@@ -32,37 +28,65 @@ 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][Support-Forum] or [the Forge Discord server][Discord].
 
-[Here is a short video from Rorax showing how to install and setup Forge.](https://www.youtube.com/watch?v=lB3ArN_-3Oc)
+## Required Java Versions
+
+We require the version of Java that Minecraft requires, which is currently:
+
+| Minecraft     | Java              |
+|---------------|-------------------|
+| 1.20.6+       | [21][Adoptium-21] |
+| 1.18 - 1.20.4 | [17][Adoptium-17] |
+| 1.17.1        | [16][Adoptium-16] |
+| 1.16.5-       | [8][Adoptium-8]   |
+
+**If you are on Windows and have difficulty using Java to launch JAR files, consider using [Jarfix by Johann Löfflmann][Jarfix].**
 
 # Creating Mods
 
-[See the "Getting Started" section in the Forge Documentation](https://mcforge.readthedocs.io/en/latest/gettingstarted/).
+[See the "Getting Started" section in the Forge Documentation](https://docs.minecraftforge.net/en/1.19.2/gettingstarted/).
 
 # Contribute to Forge
 
 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/).
+
+ [See the guide to setting up a Forge workspace](https://docs.minecraftforge.net/en/1.19.2/forgedev/).
 
 ### Pull requests
 
-[See the "Making Changes and Pull Requests" section in the Forge documentation](https://mcforge.readthedocs.io/en/latest/forgedev/#making-changes-and-pull-requests).
+[See the "Making Changes and Pull Requests" section in the Forge documentation](https://docs.minecraftforge.net/en/1.19.2/forgedev/#making-changes-and-pull-requests).
 
 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/
-[Discord]: https://discord.gg/UvedJ9m
-[Documentation]: https://mcforge.readthedocs.io
+
+[Adoptium-21]: https://adoptium.net/temurin/releases/?version=21
+[Adoptium-17]: https://adoptium.net/temurin/releases/?version=17
+[Adoptium-16]: https://adoptium.net/temurin/releases/?version=16
+[Adoptium-8]: https://adoptium.net/temurin/releases/?version=8
+[Jarfix]: https://johann.loefflmann.net/en/software/jarfix/index.html
+
+[Forum]: https://forums.minecraftforge.net/
+[Support-Forum]: https://forums.minecraftforge.net/forum/18-support-bug-reports/
+[Support-Policy]: https://forums.minecraftforge.net/topic/144690-new-tiered-support-policy
+
+[Discord]: https://discord.minecraftforge.net/
+
+[Documentation]: https://docs.minecraftforge.net/en/1.19.2/
+[Getting-Started]: https://docs.minecraftforge.net/en/1.19.2/gettingstarted/
+[ForgeDev]: https://docs.minecraftforge.net/en/1.19.2/forgedev/
+[Pull-Requests]: https://docs.minecraftforge.net/en/1.19.2/forgedev/#making-changes-and-pull-requests
+
+[Patreon]: https://www.patreon.com/LexManos

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
 

docs/assets/Forge_logo.svg

@@ -1,12 +1,7 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE svg  PUBLIC '-//W3C//DTD SVG 1.1//EN'  'http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd'>
-<svg enable-background="new 164.072 372.466 294.41 46.56" version="1.1" viewBox="164.072 372.466 294.41 46.56" xml:space="preserve" xmlns="http://www.w3.org/2000/svg">
-	<g fill="#DFA86A">
-		<polygon points="266.16 417.99 277.12 417.99 277.12 401.05 295.09 401.05 295.09 390.78 277.12 390.78 277.12 383.77 296.18 383.77 296.18 373.5 266.16 373.5"/>
-		<path d="m337.33 378.7c-2.103-2.057-4.629-3.64-7.51-4.704-2.743-1.015-5.786-1.528-9.041-1.528l-0.356 2e-3c-3.362 0-6.503 0.556-9.338 1.651-2.857 1.106-5.357 2.707-7.434 4.761-2.073 2.052-3.714 4.559-4.877 7.45-1.158 2.876-1.748 6.104-1.748 9.59 0 3.417 0.59 6.582 1.753 9.403 1.163 2.829 2.807 5.297 4.88 7.329 2.073 2.03 4.572 3.621 7.425 4.724 2.834 1.096 5.975 1.651 9.339 1.651h0.023c3.402-0.043 6.57-0.639 9.42-1.772 2.863-1.142 5.375-2.757 7.465-4.804 2.091-2.051 3.742-4.524 4.91-7.358 1.162-2.823 1.75-5.987 1.75-9.402 0-3.487-0.588-6.705-1.748-9.568-1.168-2.874-2.82-5.371-4.913-7.425zm-4.644 16.762c0 1.96-0.302 3.782-0.896 5.413-0.587 1.607-1.42 3.011-2.479 4.167-1.05 1.147-2.335 2.065-3.821 2.728-1.479 0.656-3.164 0.99-5.008 0.99-1.84 0-3.514-0.333-4.973-0.988-1.47-0.662-2.747-1.578-3.799-2.729-1.062-1.156-1.895-2.559-2.479-4.167-0.595-1.63-0.896-3.451-0.896-5.413 0-1.801 0.298-3.497 0.887-5.044 0.584-1.536 1.419-2.894 2.479-4.037 1.048-1.132 2.323-2.03 3.792-2.674 1.465-0.642 3.145-0.968 4.988-0.968 1.848 0 3.539 0.326 5.025 0.971 1.481 0.643 2.766 1.541 3.812 2.671 1.062 1.143 1.896 2.501 2.479 4.036 0.589 1.548 0.889 3.245 0.889 5.044z"/>
-		<path d="m376.27 395.65c1.902-2.327 2.867-5.221 2.867-8.603 0-2.614-0.508-4.84-1.506-6.613-0.997-1.762-2.354-3.188-4.035-4.234-1.603-0.995-3.445-1.705-5.482-2.114-1.938-0.388-3.969-0.583-6.037-0.583h-16.021v44.487h10.961v-17.282h2.35l9.447 17.282h13.127l-11.199-18.646c2.262-0.728 4.116-1.964 5.528-3.694zm-19.254-12.223h4.426c0.844 0 1.73 0.054 2.636 0.16 0.784 0.094 1.503 0.283 2.132 0.568 0.496 0.225 0.888 0.553 1.193 0.998 0.283 0.415 0.428 1.031 0.428 1.836 0 0.931-0.16 1.643-0.459 2.06-0.34 0.472-0.771 0.813-1.32 1.046-0.686 0.289-1.459 0.477-2.301 0.554-0.975 0.089-1.963 0.136-2.938 0.136h-3.795l-2e-3 -7.358z"/>
-		<path d="m394.82 386.38c1.05-1.132 2.325-2.03 3.793-2.674 1.464-0.642 3.144-0.968 4.988-0.968 1.843 0 3.611 0.311 5.26 0.921 1.609 0.599 2.992 1.449 4.107 2.531l1.314 1.278 8.019-8.105-1.454-1.298c-2.355-2.103-5.066-3.586-8.058-4.407-2.879-0.789-5.987-1.189-9.247-1.189-3.361 0-6.503 0.556-9.339 1.651-2.856 1.106-5.355 2.707-7.431 4.761-2.074 2.052-3.716 4.559-4.88 7.45-1.158 2.876-1.746 6.104-1.746 9.59 0 3.417 0.59 6.582 1.752 9.403 1.164 2.829 2.807 5.297 4.88 7.329 2.073 2.03 4.572 3.621 7.425 4.724 2.832 1.096 5.975 1.651 9.339 1.651 6.501 0 12.475-1.432 17.751-4.25l0.979-0.522v-23.814h-19.313v10.27h8.354v6.639c-0.871 0.397-1.834 0.709-2.881 0.933-1.5 0.314-3.127 0.478-4.83 0.478-1.841 0-3.514-0.333-4.973-0.988-1.472-0.662-2.748-1.578-3.801-2.729-1.06-1.156-1.893-2.559-2.478-4.167-0.595-1.63-0.896-3.451-0.896-5.413 0-1.801 0.299-3.497 0.887-5.044 0.586-1.54 1.421-2.897 2.479-4.041z"/>
-		<polygon points="437.69 407.72 437.69 400.36 456.41 400.36 456.41 390.09 437.69 390.09 437.69 383.77 457.44 383.77 457.44 373.5 426.72 373.5 426.72 417.99 458.48 417.99 458.48 407.72"/>
-	</g>
-	<path d="m243.63 379.09l-37.842-1.852 46.229-0.034v-3.727h-52.125l-1e-3 7.798v6.201c0 0.115-1.52-9.144-1.87-11.734h-4.098v13.029c0 0.123-1.753-10.888-1.939-12.264h-27.914c1.902 1.648 12.401 10.598 19.865 14.28 3.741 1.846 8.33 1.86 12.414 1.974 2.075 0.06 4.25 0.217 5.803 1.754 2.255 2.236 2.758 5.704 0.814 8.33-1.922 2.594-7.335 3.156-7.335 3.156l-4.509 5.531v6.424h10.251l0.319-6.348 8.863-6.285c-0.946 0.757-3.058 2.783-6.229 7.666-0.717 1.102-1.275 2.306-1.711 3.49 2.238-1.896 6.84-3.194 12.153-3.194 5.307 0 9.903 1.295 12.146 3.188-0.437-1.185-0.994-2.385-1.709-3.483-3.172-4.883-5.284-6.909-6.229-7.666l8.863 6.285 0.32 6.348h9.565v-6.424l-4.507-5.531s-6.675-0.425-8.423-3.156c-5.032-7.869 2.115-20.082 18.836-23.756z" fill="#1E2D41"/>
+<svg xmlns="http://www.w3.org/2000/svg" xml:space="preserve" viewBox="164.072 372.466 294.41 46.56">
+  <g fill="#DFA86A">
+    <path d="M266.16 417.99h10.96v-16.94h17.97v-10.27h-17.97v-7.01h19.06V373.5h-30.02zM337.33 378.7c-2.103-2.057-4.629-3.64-7.51-4.704-2.743-1.015-5.786-1.528-9.041-1.528l-.356.002c-3.362 0-6.503.556-9.338 1.651-2.857 1.106-5.357 2.707-7.434 4.761-2.073 2.052-3.714 4.559-4.877 7.45-1.158 2.876-1.748 6.104-1.748 9.59 0 3.417.59 6.582 1.753 9.403 1.163 2.829 2.807 5.297 4.88 7.329 2.073 2.03 4.572 3.621 7.425 4.724 2.834 1.096 5.975 1.651 9.339 1.651h.023c3.402-.043 6.57-.639 9.42-1.772 2.863-1.142 5.375-2.757 7.465-4.804 2.091-2.051 3.742-4.524 4.91-7.358 1.162-2.823 1.75-5.987 1.75-9.402 0-3.487-.588-6.705-1.748-9.568-1.168-2.874-2.82-5.371-4.913-7.425zm-4.644 16.762c0 1.96-.302 3.782-.896 5.413-.587 1.607-1.42 3.011-2.479 4.167-1.05 1.147-2.335 2.065-3.821 2.728-1.479.656-3.164.99-5.008.99-1.84 0-3.514-.333-4.973-.988-1.47-.662-2.747-1.578-3.799-2.729-1.062-1.156-1.895-2.559-2.479-4.167-.595-1.63-.896-3.451-.896-5.413 0-1.801.298-3.497.887-5.044.584-1.536 1.419-2.894 2.479-4.037 1.048-1.132 2.323-2.03 3.792-2.674 1.465-.642 3.145-.968 4.988-.968 1.848 0 3.539.326 5.025.971 1.481.643 2.766 1.541 3.812 2.671 1.062 1.143 1.896 2.501 2.479 4.036.589 1.548.889 3.245.889 5.044zM376.27 395.65c1.902-2.327 2.867-5.221 2.867-8.603 0-2.614-.508-4.84-1.506-6.613-.997-1.762-2.354-3.188-4.035-4.234-1.603-.995-3.445-1.705-5.482-2.114-1.938-.388-3.969-.583-6.037-.583h-16.021v44.487h10.961v-17.282h2.35l9.447 17.282h13.127l-11.199-18.646c2.262-.728 4.116-1.964 5.528-3.694zm-19.254-12.223h4.426c.844 0 1.73.054 2.636.16.784.094 1.503.283 2.132.568.496.225.888.553 1.193.998.283.415.428 1.031.428 1.836 0 .931-.16 1.643-.459 2.06-.34.472-.771.813-1.32 1.046-.686.289-1.459.477-2.301.554-.975.089-1.963.136-2.938.136h-3.795l-.002-7.358z"/>
+    <path d="M394.82 386.38c1.05-1.132 2.325-2.03 3.793-2.674 1.464-.642 3.144-.968 4.988-.968 1.843 0 3.611.311 5.26.921 1.609.599 2.992 1.449 4.107 2.531l1.314 1.278 8.019-8.105-1.454-1.298c-2.355-2.103-5.066-3.586-8.058-4.407-2.879-.789-5.987-1.189-9.247-1.189-3.361 0-6.503.556-9.339 1.651-2.856 1.106-5.355 2.707-7.431 4.761-2.074 2.052-3.716 4.559-4.88 7.45-1.158 2.876-1.746 6.104-1.746 9.59 0 3.417.59 6.582 1.752 9.403 1.164 2.829 2.807 5.297 4.88 7.329 2.073 2.03 4.572 3.621 7.425 4.724 2.832 1.096 5.975 1.651 9.339 1.651 6.501 0 12.475-1.432 17.751-4.25l.979-.522v-23.814h-19.313v10.27h8.354v6.639c-.871.397-1.834.709-2.881.933-1.5.314-3.127.478-4.83.478-1.841 0-3.514-.333-4.973-.988-1.472-.662-2.748-1.578-3.801-2.729-1.06-1.156-1.893-2.559-2.478-4.167-.595-1.63-.896-3.451-.896-5.413 0-1.801.299-3.497.887-5.044.586-1.54 1.421-2.897 2.479-4.041zM437.69 407.72v-7.36h18.72v-10.27h-18.72v-6.32h19.75V373.5h-30.72v44.49h31.76v-10.27z"/>
+  </g>
+  <path fill="#1E2D41" d="m243.63 379.09-37.842-1.852 46.229-.034v-3.727h-52.125l-.001 7.798v6.201c0 .115-1.52-9.144-1.87-11.734h-4.098v13.029c0 .123-1.753-10.888-1.939-12.264H164.07c1.902 1.648 12.401 10.598 19.865 14.28 3.741 1.846 8.33 1.86 12.414 1.974 2.075.06 4.25.217 5.803 1.754 2.255 2.236 2.758 5.704.814 8.33-1.922 2.594-7.335 3.156-7.335 3.156l-4.509 5.531v6.424h10.251l.319-6.348 8.863-6.285c-.946.757-3.058 2.783-6.229 7.666-.717 1.102-1.275 2.306-1.711 3.49 2.238-1.896 6.84-3.194 12.153-3.194 5.307 0 9.903 1.295 12.146 3.188-.437-1.185-.994-2.385-1.709-3.483-3.172-4.883-5.284-6.909-6.229-7.666l8.863 6.285.32 6.348h9.565v-6.424l-4.507-5.531s-6.675-.425-8.423-3.156c-5.032-7.869 2.115-20.082 18.836-23.756z"/>
 </svg>

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

@@ -1,35 +1,40 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
 package net.minecraftforge.fml;
 
-import cpw.mods.modlauncher.util.ServiceLoaderUtils;
 import net.minecraftforge.eventbus.api.IEventBus;
 import net.minecraftforge.fml.config.IConfigEvent;
 import net.minecraftforge.fml.loading.FMLLoader;
 
+import java.util.ServiceConfigurationError;
 import java.util.ServiceLoader;
 import java.util.function.Supplier;
 
 public class Bindings {
-    private static final Bindings INSTANCE = new Bindings();
+    private Bindings() {}
 
-    private final IBindingsProvider provider;
-
-    private Bindings() {
-        final var providers = ServiceLoaderUtils.streamServiceLoader(()->ServiceLoader.load(FMLLoader.getGameLayer(), IBindingsProvider.class), sce->{}).toList();
-        if (providers.size() != 1) {
-            throw new IllegalStateException("Could not find bindings provider");
-        }
-        this.provider = providers.get(0);
-    }
+    /**
+     * The provider of the bindings
+     * @implNote May also throw a {@link ServiceConfigurationError}
+     */
+    private static final IBindingsProvider PROVIDER = ServiceLoader.load(FMLLoader.getGameLayer(), IBindingsProvider.class)
+            .findFirst().orElseThrow(() -> new IllegalStateException("Could not find bindings provider"));
 
+    /**
+     * @return A supplier of net.minecraftforge.common.MinecraftForge#EVENT_BUS
+     */
     public static Supplier<IEventBus> getForgeBus() {
-        return INSTANCE.provider.getForgeBusSupplier();
+        return PROVIDER.getForgeBusSupplier();
     }
 
     public static Supplier<I18NParser> getMessageParser() {
-        return INSTANCE.provider.getMessageParser();
+        return PROVIDER.getMessageParser();
     }
 
     public static Supplier<IConfigEvent.ConfigConfig> getConfigConfiguration() {
-        return INSTANCE.provider.getConfigConfiguration();
+        return PROVIDER.getConfigConfiguration();
     }
 }

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 +8,111 @@ 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";
+
+        /**
+         * Ignores any version information coming from the server - use for server only mods
+         */
+        public static final Supplier<DisplayTest> IGNORE_SERVER_VERSION = () -> new DisplayTest(IGNORESERVERONLY, (remoteVersion, isFromServer) -> true);
+
+        /**
+         * Ignores all information and provides no information
+         */
+        public static final Supplier<DisplayTest> IGNORE_ALL_VERSION = () -> new DisplayTest("", (remoteVersion, isFromServer) -> true);
+
+        /**
+         * An optional alternative to {@link #DisplayTest(Supplier, BiPredicate)} which accepts a constant version string
+         * instead of a {@link Supplier}.
+         * <p>Internally, the provided version string is wrapped in a Supplier for you.</p>
+         */
+        public DisplayTest(String version, BiPredicate<String, Boolean> remoteVersionTest) {
+            this(() -> version, remoteVersionTest);
+        }
+    }
 }

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;
@@ -23,6 +9,7 @@ import net.minecraftforge.eventbus.api.Event;
 import net.minecraftforge.fml.config.IConfigEvent;
 import net.minecraftforge.fml.config.ModConfig;
 import net.minecraftforge.fml.event.IModBusEvent;
+import net.minecraftforge.fml.loading.moddiscovery.ModFileInfo;
 import net.minecraftforge.forgespi.language.IModInfo;
 
 import java.util.EnumMap;
@@ -34,6 +21,7 @@ import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.Executor;
 import java.util.function.BiFunction;
+import java.util.function.BiPredicate;
 import java.util.function.Consumer;
 import java.util.function.Supplier;
 
@@ -70,9 +58,25 @@ 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")
+                .orElseGet(() -> (Boolean) info.getOwningFile().getFileProperties().getOrDefault(ModFileInfo.CLIENT_SIDE_ONLY_PROP, Boolean.FALSE) ? "IGNORE_ALL_VERSION" : "MATCH_VERSION");
+        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
+                    IExtensionPoint.DisplayTest.IGNORE_SERVER_VERSION;
+            case "IGNORE_ALL_VERSION" -> // Ignores all information and provides no information
+                    IExtensionPoint.DisplayTest.IGNORE_ALL_VERSION;
+            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);
     }
 
     /**
@@ -141,6 +145,22 @@ public abstract class ModContainer
         extensionPoints.put(point, extension);
     }
 
+    public void registerDisplayTest(IExtensionPoint.DisplayTest displayTest) {
+        registerExtensionPoint(IExtensionPoint.DisplayTest.class, () -> displayTest);
+    }
+
+    public void registerDisplayTest(Supplier<IExtensionPoint.DisplayTest> displayTest) {
+        registerExtensionPoint(IExtensionPoint.DisplayTest.class, displayTest);
+    }
+
+    public void registerDisplayTest(String version, BiPredicate<String, Boolean> remoteVersionTest) {
+        registerDisplayTest(new IExtensionPoint.DisplayTest(version, remoteVersionTest));
+    }
+
+    public void registerDisplayTest(Supplier<String> suppliedVersion, BiPredicate<String, Boolean> remoteVersionTest) {
+        registerDisplayTest(new IExtensionPoint.DisplayTest(suppliedVersion, remoteVersionTest));
+    }
+
     public void addConfig(final ModConfig modConfig) {
        configs.put(modConfig.getType(), modConfig);
     }

fmlcore/src/main/java/net/minecraftforge/fml/ModList.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;
@@ -35,8 +21,9 @@ 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;
 import java.util.Objects;
 import java.util.Optional;
@@ -67,6 +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)
     {
@@ -85,7 +73,7 @@ public class ModList
     }
 
     private String fileToLine(IModFile mf) {
-        return String.format("%-50.50s|%-30.30s|%-30.30s|%-20.20s|%-10.10s|Manifest: %s", mf.getFileName(),
+        return String.format(Locale.ENGLISH, "%-50.50s|%-30.30s|%-30.30s|%-20.20s|%-10.10s|Manifest: %s", mf.getFileName(),
                 mf.getModInfos().get(0).getDisplayName(),
                 mf.getModInfos().get(0).getModId(),
                 mf.getModInfos().get(0).getVersion(),
@@ -124,7 +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(
@@ -133,12 +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 -> {
@@ -169,6 +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()));
     }
 
@@ -232,6 +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;
@@ -22,18 +8,22 @@ 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.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
@@ -42,6 +32,7 @@ import java.util.Optional;
 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 +101,7 @@ 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 +138,7 @@ 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 +151,22 @@ 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 +218,7 @@ 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 +244,7 @@ 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()));
 
@@ -258,7 +266,7 @@ public class ModLoader
         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 +295,7 @@ 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 +303,18 @@ 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> 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

@@ -1,54 +1,61 @@
 /*
- * 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 org.slf4j.Logger;
 
+import java.util.function.BiPredicate;
 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 ModContainer activeContainer;
     private Object languageExtension;
     private ModLoadingStage stage;
 
+    /**
+     * @deprecated Use the context provided by your language loader in your mod's constructor.
+     */
+    @Deprecated(forRemoval = true, since = "1.21.1")
     public static ModLoadingContext get() {
         return context.get();
     }
 
-    private ModContainer activeContainer;
-
+    /**
+     * @deprecated Going to be moved to ForgeHooks for internal use.
+     */
+    @Deprecated(forRemoval = true, since = "1.21.1")
     public void setActiveContainer(final ModContainer container) {
         this.activeContainer = container;
         this.languageExtension = container == null ? null : container.contextExtension.get();
     }
 
+    /**
+     * Going to be moved to ForgeHooks for internal use.
+     * @deprecated Override/Use {@link ModLoadingContext#getContainer()}
+     */
+    @Deprecated(forRemoval = true, since = "1.21.1")
     public ModContainer getActiveContainer() {
         return activeContainer == null ? ModList.get().getModContainerById("minecraft").orElseThrow(()->new RuntimeException("Where is minecraft???!")) : activeContainer;
     }
 
+    @Deprecated(forRemoval = true, since = "1.21.1")
     public String getActiveNamespace() {
         return activeContainer == null ? "minecraft" : activeContainer.getNamespace();
     }
 
+    public ModContainer getContainer() {
+        return getActiveContainer();
+    }
+
     /**
      * Register an {@link IExtensionPoint} with the mod container.
      * @param point The extension point to register
@@ -56,15 +63,67 @@ public class ModLoadingContext
      * @param <T> The type signature of the extension operator
      */
     public <T extends Record & IExtensionPoint<T>> void registerExtensionPoint(Class<? extends IExtensionPoint<T>> point, Supplier<T> extension) {
-        getActiveContainer().registerExtensionPoint(point, extension);
+        getContainer().registerExtensionPoint(point, extension);
+    }
+
+    /**
+     * Register a {@link IExtensionPoint.DisplayTest} with the mod container.
+     * <p>A shorthand for registering a DisplayTest with {@link #registerExtensionPoint(Class, Supplier)}.</p>
+     * @param displayTest The {@link IExtensionPoint.DisplayTest} to register
+     */
+    public void registerDisplayTest(IExtensionPoint.DisplayTest displayTest) {
+        getContainer().registerDisplayTest(() -> displayTest);
+    }
+
+    /**
+     * Register a {@link IExtensionPoint.DisplayTest} with the mod container.
+     * <p>A shorthand for registering a DisplayTest supplier with {@link #registerExtensionPoint(Class, Supplier)}.</p>
+     * @param displayTest The {@link Supplier<IExtensionPoint.DisplayTest>} to register
+     */
+    public void registerDisplayTest(Supplier<IExtensionPoint.DisplayTest> displayTest) {
+        getContainer().registerDisplayTest(displayTest);
+    }
+
+    /**
+     * Register a {@link IExtensionPoint.DisplayTest} with the mod container.
+     * <p>A shorthand for registering a DisplayTest with {@link #registerExtensionPoint(Class, Supplier)} that also
+     * creates the DisplayTest instance for you using the provided parameters.</p>
+     * @see IExtensionPoint.DisplayTest#DisplayTest(String, BiPredicate)
+     */
+    public void registerDisplayTest(String version, BiPredicate<String, Boolean> remoteVersionTest) {
+        getContainer().registerDisplayTest(new IExtensionPoint.DisplayTest(version, remoteVersionTest));
+    }
+
+    /**
+     * Register a {@link IExtensionPoint.DisplayTest} with the mod container.
+     * <p>A shorthand for registering a DisplayTest with {@link #registerExtensionPoint(Class, Supplier)} that also
+     * creates the DisplayTest instance for you using the provided parameters.</p>
+     * @see IExtensionPoint.DisplayTest#DisplayTest(Supplier, BiPredicate)
+     */
+    public void registerDisplayTest(Supplier<String> suppliedVersion, BiPredicate<String, Boolean> remoteVersionTest) {
+        getContainer().registerDisplayTest(new IExtensionPoint.DisplayTest(suppliedVersion, remoteVersionTest));
     }
 
     public void registerConfig(ModConfig.Type type, IConfigSpec<?> spec) {
-        getActiveContainer().addConfig(new ModConfig(type, spec, getActiveContainer()));
+        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, getContainer().getModId());
+            return;
+        }
+
+        getContainer().addConfig(new ModConfig(type, spec, getContainer()));
     }
 
     public void registerConfig(ModConfig.Type type, IConfigSpec<?> spec, String fileName) {
-        getActiveContainer().addConfig(new ModConfig(type, spec, getActiveContainer(), 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, getContainer().getModId(), fileName);
+            return;
+        }
+
+        getContainer().addConfig(new ModConfig(type, spec, getContainer(), 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());
 
@@ -81,6 +67,7 @@ public class ConfigFileTypeHandler {
     }
 
     private boolean setupConfigFile(final ModConfig modConfig, final Path file, final ConfigFormat<?> conf) throws IOException {
+        Files.createDirectories(file.getParent());
         Path p = defaultConfigPath.resolve(modConfig.getFileName());
         if (Files.exists(p)) {
             LOGGER.info(CONFIG, "Loading default config file from path {}", p);

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) 2016-2021.
- *
- * 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;
@@ -27,6 +13,7 @@ import net.minecraftforge.fml.loading.StringUtils;
 
 import java.io.ByteArrayInputStream;
 import java.nio.file.Path;
+import java.util.Locale;
 import java.util.concurrent.Callable;
 
 public class ModConfig
@@ -54,7 +41,7 @@ public class ModConfig
 
     private static String defaultConfigName(Type type, String modId) {
         // config file name would be "forge-client.toml" and "forge-server.toml"
-        return String.format("%s-%s.toml", modId, type.extension());
+        return String.format(Locale.ROOT, "%s-%s.toml", modId, type.extension());
     }
     public Type getType() {
         return type;

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'
@@ -10,28 +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:21.0.0')
+    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:2.14.1')
-    api('com.google.guava:guava:21.0')
-    api('com.google.code.gson:gson:2.8.0')
-    api('org.apache.maven:maven-artifact:3.8.1')
-    api('org.apache.commons:commons-lang3:3.8.1')
-    api('com.electronwill.night-config:core:3.6.3')
-    api('com.electronwill.night-config:toml:3.6.3')
-    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:2.14.1')
-    annotationProcessor('org.apache.logging.log4j:log4j-core:2.14.1')
-    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}")
 }
 
@@ -69,6 +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 +1,18 @@
 /*
- * 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.common.asm;
 
 import java.util.EnumSet;
 import java.util.List;
+import java.util.Map;
+import java.util.Set;
 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;
@@ -34,26 +25,56 @@ import cpw.mods.modlauncher.serviceapi.ILaunchPluginService;
  * Will also de-finalize all fields in on class level annotations.
  */
 public class ObjectHolderDefinalize implements ILaunchPluginService {
-
-    private final String OBJECT_HOLDER = "Lnet/minecraftforge/registries/ObjectHolder;"; //Don't directly reference this to prevent class loading.
+    // 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 static final Set<String> VANILLA_OBJECT_HOLDER_CLASSES = VANILLA_OBJECT_HOLDERS.keySet().stream()
+            .map(it -> it.replace('.', '/'))
+            .collect(Collectors.toUnmodifiableSet());
+    private static final String OBJECT_HOLDER = "Lnet/minecraftforge/registries/ObjectHolder;"; //Don't directly reference this to prevent class loading.
+    private static final int PUBLIC_STATIC_FINAL_FLAGS = Opcodes.ACC_PUBLIC | Opcodes.ACC_STATIC | Opcodes.ACC_FINAL;
 
     @Override
     public String name() {
         return "object_holder_definalize";
     }
 
-
     private static final EnumSet<Phase> YAY = EnumSet.of(Phase.AFTER);
     private static final EnumSet<Phase> NAY = EnumSet.noneOf(Phase.class);
 
     @Override
-    public EnumSet<Phase> handlesClass(Type classType, boolean isEmpty)
-    {
-        return isEmpty ? NAY : YAY;
+    public EnumSet<Phase> handlesClass(Type classType, boolean isEmpty) {
+        if (isEmpty)
+            return NAY;
+
+        // Let's skip processing classes that definitely don't have object holders
+        String internalName = classType.getInternalName();
+
+        // Forge classes that aren't in the debug package (that package is used for tests)
+        if (internalName.startsWith("net/minecraftforge/") && !internalName.substring(18).contains("debug")
+            && !internalName.equals("net/minecraftforge/common/crafting/ConditionalRecipe"))
+            return NAY;
+
+        // Vanilla classes that don't have object holders
+        if (internalName.startsWith("com/mojang/"))
+            return NAY;
+
+        // ...except specific ones we added to the VANILLA_OBJECT_HOLDERS map
+        if (internalName.startsWith("net/minecraft/") && !VANILLA_OBJECT_HOLDER_CLASSES.contains(internalName))
+            return NAY;
+
+        return YAY;
     }
 
-    private boolean hasHolder(List<AnnotationNode> lst)
-    {
+    private boolean hasHolder(List<AnnotationNode> lst) {
         return lst != null && lst.stream().anyMatch(n -> n.desc.equals(OBJECT_HOLDER));
     }
 
@@ -76,10 +97,9 @@ public class ObjectHolderDefinalize implements ILaunchPluginService {
     {
         final AtomicBoolean changes = new AtomicBoolean();
         //Must be public static finals, and non-array objects
-        final int flags = Opcodes.ACC_PUBLIC | Opcodes.ACC_STATIC | Opcodes.ACC_FINAL;
 
         //Fix Annotated Fields before injecting from class level
-        classNode.fields.stream().filter(f -> ((f.access & flags) == flags) && f.desc.startsWith("L") && hasHolder(f.visibleAnnotations)).forEach(f ->
+        classNode.fields.stream().filter(f -> ((f.access & PUBLIC_STATIC_FINAL_FLAGS) == PUBLIC_STATIC_FINAL_FLAGS) && f.desc.startsWith("L") && hasHolder(f.visibleAnnotations)).forEach(f ->
         {
             int prev = f.access;
             f.access &= ~Opcodes.ACC_FINAL; //Strip final
@@ -87,11 +107,9 @@ 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 ->
+            classNode.fields.stream().filter(f -> ((f.access & PUBLIC_STATIC_FINAL_FLAGS) == PUBLIC_STATIC_FINAL_FLAGS) && f.desc.startsWith("L")).forEach(f ->
             {
                 int prev = f.access;
                 f.access &= ~Opcodes.ACC_FINAL;
@@ -109,4 +127,5 @@ 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 +62,50 @@ 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());
         }
 
+        // Allows us to communicate properties with other services through ModLauncher
+        setupBlackboardKeys();
+
         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 +117,7 @@ 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");
         }
 
@@ -136,11 +125,17 @@ 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");
         }
     }
 
+    private static void setupBlackboardKeys() {
+        LOGGER.debug(CORE, "Requesting CoreMods to not apply the fix for ASMAPI.findFirstInstructionBefore by default");
+        var blackboardKey = TypesafeMap.Key.getOrCreate(Launcher.INSTANCE.blackboard(), "coremods.use_old_findFirstInstructionBefore", Boolean.class);
+        Launcher.INSTANCE.blackboard().<Boolean>computeIfAbsent(blackboardKey, k -> true);
+    }
+
     static void setupLaunchHandler(final IEnvironment environment, final Map<String, Object> arguments)
     {
         final String launchTarget = environment.getProperty(IEnvironment.Keys.LAUNCHTARGET.get()).orElse("MISSING");
@@ -148,12 +143,12 @@ 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 +18,15 @@ 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;
 
 import static java.util.stream.Collectors.*;
@@ -45,15 +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)
@@ -63,13 +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;
@@ -88,11 +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)
@@ -108,11 +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))
@@ -135,10 +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()) {
@@ -149,62 +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()
@@ -233,6 +209,27 @@ public class ModSorter
         LOGGER.debug(LOADING, "Found {} mod requirements missing ({} mandatory, {} optional)", missingVersions.size(), mandatoryMissing, missingVersions.size() - mandatoryMissing);
 
         if (!missingVersions.isEmpty()) {
+            if (mandatoryMissing > 0) {
+                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:\n{}",
+                        missingVersions.stream()
+                                .filter(ver -> !ver.isMandatory())
+                                .map(ver -> formatDependencyError(ver, modVersions))
+                                .collect(Collectors.joining("\n"))
+                );
+            }
+
             return missingVersions.stream()
                     .map(mv -> new ExceptionData(mv.isMandatory() ? "fml.modloading.missingdependency" : "fml.modloading.missingdependency.optional",
                             mv.getOwner(), mv.getModId(), mv.getOwner().getModId(), mv.getVersionRange(),
@@ -242,6 +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 +1,145 @@
+/*
+ * 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.ArrayList;
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+import static java.util.stream.Collectors.groupingBy;
+import static java.util.stream.Collectors.joining;
+import static net.minecraftforge.fml.loading.LogMarkers.LOADING;
+
+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<String> dupedModErrors = modIds.values().stream()
+                .filter(modInfos -> modInfos.size() > 1)
+                .map(mods -> String.format("\tMod ID: '%s' from mod files: %s",
+                        mods.get(0).getModId(),
+                        mods.stream()
+                                .map(modInfo -> modInfo.getOwningFile().getFile().getFileName()).collect(joining(", "))
+                )).toList();
+
+        if (!dupedModErrors.isEmpty()) {
+            LOGGER.error(LOADING, "Found duplicate mods:\n{}", dupedModErrors.stream().collect(joining("\n")));
+            throw new EarlyLoadingException("Duplicate mods found", null, dupedModErrors.stream()
+                    .map(s -> new EarlyLoadingException.ExceptionData(s))
+                    .toList());
+        }
+
+        final List<String> dupedLibErrors = versionedLibIds.values().stream()
+                .filter(modFiles -> modFiles.size() > 1)
+                .map(mods -> String.format("\tLibrary: '%s' from files: %s",
+                        getModId(mods.get(0)),
+                        mods.stream()
+                                .map(modFile -> modFile.getFileName()).collect(joining(", "))
+                )).toList();
+
+        if (!dupedLibErrors.isEmpty()) {
+            LOGGER.error(LOADING, "Found duplicate plugins or libraries:\n{}", dupedLibErrors.stream().collect(joining("\n")));
+            throw new EarlyLoadingException("Duplicate plugins or libraries found", null, dupedLibErrors.stream()
+                    .map(s -> new EarlyLoadingException.ExceptionData(s))
+                    .toList());
+        }
+
+        // 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;