CleanroomGradle

Gradle plugin for Cleanroom Loader development and Cleanroom-targeted mod development. The current release is 0.9.1.

Applying the plugin

The settings plugin adds the Cleanroom, Forge, Mojang, and Maven Central dependency repositories and configures Foojay toolchain resolution. The project plugin registers the Minecraft toolchain and development tasks.

// settings.gradle
pluginManagement {
    repositories {
        maven {
            url = 'https://maven.cleanroommc.com'
        }
        maven {
            url = 'https://maven.minecraftforge.net/'
        }
        gradlePluginPortal()
    }
}

plugins {
    id 'com.cleanroommc.cleanroomgradle.settings' version '0.9.1'
}

// build.gradle
plugins {
    id 'java'
    id 'com.cleanroommc.cleanroomgradle'
}

Project Mode

Choose the pipeline explicitly for predictable task registration:

import com.cleanroommc.gradle.api.ext.ProjectMode

cleanroom {
    mode = ProjectMode.USERDEV // VANILLA, LOADER, or default: USERDEV
    version = '0.7.0-alpha'
}

Mode	Purpose
VANILLA	Vanilla download, run, decompile, and shared MCP facilities only
LOADER	Cleanroom loader sources, SAS/AT processing, run tasks, and distribution artifacts
USERDEV	Mod workspace backed by cleanroomVersion or a cleanroomUserdev dependency

The default is USERDEV, since mod development is the primary use case. Loader development and standalone vanilla tooling must select LOADER or VANILLA explicitly.

USERDEV requires one of:

cleanroom {
    version '0.7.0-alpha'
}

// or
dependencies {
    cleanroomUserdev 'com.cleanroommc:cleanroom:0.7.0:userdev@jar'
}

Useful Configuration

cleanroom {
    // Optional cache overrides, shared downloads use Gradle user home by default
    cacheDirectory = layout.projectDirectory.dir('.gradle/cleanroom-shared')
    versionCacheDirectory = layout.projectDirectory.dir('.gradle/cleanroom-shared/versions/1.12.2')

    // Project-local generated/intermediate data
    localCacheDirectory = layout.buildDirectory.dir('cleanroom_gradle')

    // Loader defaults false; other modes default true
    discardIntermediates = true

    // Optional editable Tiny v2 source at <directory>/mappings.tiny
    namesDirectory = layout.projectDirectory.dir('mappings')

    accessTransformers.from('src/main/resources/META-INF/accesstransformer.cfg')
    sideAnnotationStrippers.from('src/main/resources/META-INF/side_annotation_stripper.cfg')
}

Use -Pmc=<version> to select another Minecraft version through Mojang's launcher manifest. Use -Pcleanroom.vanillaJava=<major> to override the Java launcher selected for vanilla Minecraft.

The mc property remains a shortcut for selecting the version used by the original unsuffixed tasks. Named vanilla environments are available in every project mode, including the default USERDEV mode. For several versions in one project, declare them together:

cleanroom {
    vanilla {
        "1.4.7" {
            client {
                args '--demo'
                maxHeapSize = '2G'
            }
            server {
                args '--custom-server-argument'
            }
        }
        "26.1" {
            javaVersion = 25 // optional - defaults to launcher metadata
        }
    }
}

An environment name defaults to its Minecraft version and becomes part of its task names: The example creates run1.4.7Client, run1.4.7Server, decompile1.4.7, run26.1Client, and their version-specific download tasks. Dots are valid in Gradle task names, so quoted version strings are kept exactly. Letters, numbers, dots, underscores, and hyphens are accepted in environment names.

An alias can target a different version:

cleanroom {
    vanilla {
        legacy {
            version = '1.4.7'
        }
    }
}

That creates runLegacyClient while caching the Minecraft data under version 1.4.7. Named environments share downloaded assets and per-version metadata/JARs, but use isolated dependency configurations, extracted natives, and run directories. Launcher metadata supplies each vanilla client's main class and arguments. Compatibility is still ultimately constrained by the launch protocol and Java requirements of the selected Minecraft version.

Entry-point tasks

Area	Tasks
Diagnostics	cleanroomInfo
Vanilla	decompileVersion, runVanillaClient, runVanillaServer, plus decompile<name> and run<name>Client/Server for named environments
MCP/loader	runSrgClient, runSrgServer, runMcpClient, runMcpServer, importMcpNames
Loader	runCleanroomClient, runCleanroomServer, universalJar, userdevJar, javadocJar, publishMmcPackZip
Userdev	setupCleanroom, runClient, runServer, decompileDevJar, reobfJar

Run ./gradlew tasks --all for the complete pipeline.

Diagnostics and Offline Use

./gradlew cleanroomInfo

The report shows the effective mode, Minecraft version, names source, cache paths, configured/default tool versions, intermediate policy, and whether the client JAR, server JAR, and asset index are ready for offline use. It does not resolve or download tool artifacts.

Before using --offline, run the relevant setup or client task online once. downloadAssets --offline validates all indexed objects and reports missing/corrupt assets together with a repair command. Configuration and task validation failures use Gradle's Problems API where Gradle exposes it, so IDEs and the generated build/reports/problems/problems-report.html receive structured problem IDs, details, locations, and suggested fixes.

Cache Behavior

Gradle build-cache and configuration-cache support are enabled by this project's defaults. Expensive deterministic transforms including: decompilation, mappings, access transformation, SAS, and binpatch work declare cacheable inputs and outputs.

• clean deletes the build directory and localCacheDirectory as it preserves shared Minecraft downloads.
• cleanCleanroomSharedCache explicitly deletes the configured shared cacheDirectory.
• cleanroom.discardIntermediates=true deletes consumed project-local pipeline artifacts - cacheable tasks can restore them later.

For shared CI reuse, configure a Gradle local or remote build cache in the consuming build's settings.gradle; CleanroomGradle does not choose credentials or a cache server for you.

Replacing Tools

Tool configurations use defaults only while empty. Add a dependency to replace a tool without changing task wiring:

dependencies {
    decompiler 'example:replacement-decompiler:1.0'
    mergetool 'example:replacement-merger:1.0'
    mcinjector 'example:replacement-injector:1.0'
    accesstransformer 'example:replacement-at:1.0'
    installertools 'example:replacement-installer-tools:1.0'
}

If the replacement has a different command line, configure the corresponding MavenJarExec task with useDefaultToolArguments = false, mainClass, and args.