Issue with setting up MCP/Mixins

Plugins Plugin Development
1

Im trying to set up a workspace for a new plugin (mc 1.12.2, forge) but I keep getting a gradle error… What am I missing?

build.gradle:

buildscript {
    repositories {
        maven {
            name = 'sponge'
            url = 'https://repo.spongepowered.org/maven'
        }
        maven {
            name = 'forge'
            url = 'https://files.minecraftforge.net/maven'
        }
    }
    dependencies {
        classpath 'net.minecraftforge.gradle:ForgeGradle:2.3-SNAPSHOT'
        classpath 'org.spongepowered:mixingradle:0.6-SNAPSHOT'
    }
}

plugins {
    id 'org.spongepowered.plugin' version '0.8.1'
}

apply plugin: 'net.minecraftforge.gradle.forge'
apply plugin: "org.spongepowered.mixin"

group = 'com.myplugin'
version = '2.0-SNAPSHOT'
description = 'BALBLABLA'

dependencies {
    compile 'org.spongepowered:spongeapi:7.1.0'
    compile 'org.spongepowered:mixin:0.7.5-SNAPSHOT'
}

minecraft {
    forgeVersion = '2611'
    mappings = 'snapshot_20180227'
}

sourceSets {
    main {
        refMap = "mixins.myplugin.refmap.json"
    }
}

jar {
    manifest.attributes(
            'TweakClass': 'org.spongepowered.asm.launch.MixinTweaker',
            'MixinConfigs': 'mixins.myplugin.json',
            'FMLCorePluginContainsFMLMod': 'true',
    )
}

Error:

* Where:
Build file '../../../build.gradle' line: 22

* What went wrong:
A problem occurred evaluating root project 'plugin'.
> Failed to apply plugin [id 'net.minecraftforge.gradle.forge']
   > MISSING REPLACEMENT DATA FOR RUN_DIR

Line 22 in build.gradle:

apply plugin: 'net.minecraftforge.gradle.forge'

Last time I did it it worked out, but that project is gone, so I have to set up a new one.
Thanks in advance!

2

downgrade gradle and/or use the wrapper that comes with the MDK