python-mixins.gradle

// This script can be applied by any Python mod by adding this to their build.gradle:
// apply from: "python-mixins.gradle"
// It ensures that Python Mixins are compiled into Java before the Java compilation step.

task generatePythonMixins(type: Exec) {
    def pythonSrcDir = file("src/main/python")
    def genJavaDir = file("build/generated/sources/mixins/java")

    // Only run this task if the mod actually has a Python source directory
    onlyIf {
        pythonSrcDir.exists()
    }

    // Set Gradle inputs/outputs for build caching and UP-TO-DATE checks
    if (pythonSrcDir.exists()) {
        inputs.dir(pythonSrcDir)
    }
    outputs.dir(genJavaDir)

    // Execute the Python AST compiler script.
    // Note: This requires a working Python installation on the system PATH.
    commandLine 'python', 'mixin_generator.py', pythonSrcDir.absolutePath, genJavaDir.absolutePath
}

// Hook the custom task into the standard Gradle lifecycle.
// We must generate the Java mixin files BEFORE the Java compiler runs.
tasks.named('compileJava').configure {
    dependsOn 'generatePythonMixins'
}
tasks.matching { it.name == 'sourcesJar' }.configureEach {
    dependsOn 'generatePythonMixins'
}

// Tell the Java compiler to include the dynamically generated Java files in its source set
sourceSets {
    main {
        java {
            srcDirs += 'build/generated/sources/mixins/java'
        }
        resources {
            srcDirs += 'src/main/python'
        }
    }
}