build.gradle

buildscript {
    repositories {
        // for early access Kotlin versions
        maven { url = 'https://files.minecraftforge.net/maven' }
        jcenter()
        mavenCentral()
    }
    dependencies {
        classpath group: 'net.minecraftforge.gradle', name: 'ForgeGradle', version: '3.+', changing: true
        // Make sure this version matches the one included in Kotlin for Forge
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.4.0"
    }
}
apply plugin: 'net.minecraftforge.gradle'
apply plugin: 'kotlin'

version = '1.0.0'
group = 'example.examplemod'
archivesBaseName = 'examplemod'

sourceCompatibility = targetCompatibility = compileJava.sourceCompatibility = compileJava.targetCompatibility = '1.8'

minecraft {
    // Change to your preferred mappings
    mappings channel: 'snapshot', version: '20200620-1.15.1'
    // Add your AccessTransformer
    // accessTransformer = file('src/main/resources/META-INF/accesstransformer.cfg')

    runs {
        client {
            workingDirectory project.file('run')

            property 'forge.logging.console.level', 'debug'

            mods {
                examplemod {
                    source sourceSets.main
                }
            }
        }

        server {
            workingDirectory project.file('run')

            property 'forge.logging.console.level', 'debug'

            mods {
                examplemod {
                    source sourceSets.main
                }
            }
        }

        data {
            workingDirectory project.file('run')

            property 'forge.logging.console.level', 'debug'

            args '--mod', 'examplemod', '--all', '--output', file('src/generated/resources/')

            mods {
                examplemod {
                    source sourceSets.main
                }
            }
        }
    }
}

repositories {
    maven {
        name = 'Kotlin for Forge'
        url = 'https://thedarkcolour.github.io/KotlinForForge/'
    }
}

dependencies {
    // Use the latest version of Minecraft Forge
    minecraft 'net.minecraftforge:forge:1.15.2-31.2.19'

    // Use the latest version of KotlinForForge
    fg.deobf(implementation('thedarkcolour:kotlinforforge:1.5.0'))
}

compileKotlin {
    kotlinOptions {
        jvmTarget = '1.8'
        languageVersion = '1.4'
        apiVersion = '1.4'
    }
}

// Optional (include assets and data from 'generated' folder)
sourceSets.main.resources {
    srcDirs 'src/generated/resources/'
}

jar {
    manifest {
        attributes([
                "Specification-Title": "examplemod",
                "Specification-Vendor": "examplemodsareus",
                "Specification-Version": "1", // We are version 1 of ourselves
                "Implementation-Title": project.name,
                "Implementation-Version": "${version}",
                "Implementation-Vendor" :"examplemodsareus",
                "Implementation-Timestamp": new Date().format("yyyy-MM-dd'T'HH:mm:ssZ")
        ])
    }
}