Glue

Gradle plugin that helps build multi-version Fabric Minecraft mods by glueing together multiple builds.

"Glueing" (sic) means combining the jars, overwriting existing files - except for the fabric.mod.json, mixin configurations and refmap JSON files.
These 3 types of files are instead combined as a sort of map/object, where existing entries are overwritten or combined if they are objects or lists.

Setup

build.gradle:

plugins {
    id 'glue' version '0.0.7'
}

settings.gradle:

pluginManagement {
    repositories {
        maven {
            name = "Fourmisain's Maven"
            url = "https://gitlab.com/api/v4/projects/37712942/packages/maven"
        }
    }
}

Configuring

build.gradle example:

glue {
    // subproject names in the order they'll be glued
    targets = ['legacy', 'main', 'glue']

    // the output file name (without ".jar"), defaults to "${project.archives_base_name}-${project.mod_version}"
    // note: the output path is "build/libs"
    outputName = "${project.archives_base_name}-${project.mod_version}-universal"

    // the input file name (without ".jar") for each target, defaults to "${subproject.archives_base_name}-${subproject.mod_version}"
    // note: the input path is "${target}/build/libs"
    inputNames = [
        legacy: 'testName'  // overrides the input filename for the 'legacy' target
    ]

    // overrides allow you to change or remove top-level entries in the 3 types of JSON files
    overrides = [
        'fabric.mod.json': [
            'mixins': null
        ]
    ]

    // there's also more general JSON file transforms if needed (note: this disables task caching)
    transform('fabric.mod.json') {
        it['authors'] += 'Glue'
    }
}

Building

Build with gradle build or gradle glue

Example

The easiest way to understand how to use this plugin is to look at an example usage: Creative One-Punch

This mod has the legacy and main subprojects, which build the mod for old and modern Minecraft versions.
Since the mod only uses one simple Mixin, the idea is to add a Mixin plugin which applies the correct Mixin from either build based on the Minecraft version that's running - this is what the glue subproject is supposed to do.

The java files all have unique names/paths to ensure they won't be overwritten. The Mixins need to live in the same base package (but can be in sub packages) - in this case one of the Mixins simply has Legacy in its name, which is also used to determine if it should run on old Minecraft versions or not.

Inside build.gradle, Glue is configured to glue legacy, main, glue in order, hence glue gets to decide e.g. the Minecraft version range in fabric.mod.json and especially the plugin value in creativeonepunch.mixins.json.