If I run CC-Tweaked with IntelliJ, I always get this Error:

I setup the Mod with this Commands:

./gradlew --stacktrace setupDecompWorkspace --refresh-dependencies
./gradlew --stacktrace cleanIdea idea

Can you upload your run configuration and see if there's anything in the logs? I've never come across this issue, so I suspect it's an issue with your setup.

Here is the log

btw:
The Error message is a liitle bit broken on Pocket Computers:

./gradlew runClient works!

Here's the run configuration:

If I load a World that I created in a IntelliJ Instance with a gradlew runClient, I get this Error:

Here's the run configuration:

On the "Use classpath of module" section, see if you can select cc-tweaked-1.12.2-main instead. If that doesn't work, then I'm at a loss.

If I load a World that I created in a IntelliJ Instance with a gradlew runClient, I get this Error:

Yeah, ForgeGradle/IntelliJ integration is a little broken so MCMultipart + Charset get injected into the wrong scope. It's OK to hit yes.

There is no cc-tweaked-1.12.2-main. There is only cc-tweaked-1.12.2.

[20:24:24] [main/ERROR] [FML]: Unable to read a class file correctly
java.lang.IllegalArgumentException: null
	at org.objectweb.asm.ClassReader.<init>(ClassReader.java:185) ~[asm-debug-all-5.2.jar:5.2]
	at org.objectweb.asm.ClassReader.<init>(ClassReader.java:168) ~[asm-debug-all-5.2.jar:5.2]
	at org.objectweb.asm.ClassReader.<init>(ClassReader.java:439) ~[asm-debug-all-5.2.jar:5.2]
[20:24:25] [main/WARN] [FML]: Zip file junit-platform-commons-1.1.0.jar failed to read properly, it will be ignored
net.minecraftforge.fml.common.LoaderException: java.lang.IllegalArgumentException

	at net.minecraftforge.fml.common.discovery.asm.ASMModParser.<init>(ASMModParser.java:63) ~[ASMModParser.class:?]
	at net.minecraftforge.fml.common.discovery.JarDiscoverer.findClassesASM(JarDiscoverer.java:102) ~[JarDiscoverer.class:?]
	at net.minecraftforge.fml.common.discovery.JarDiscoverer.discover(JarDiscoverer.java:77) [JarDiscoverer.class:?]

Well, these are somewhat concerning. A couple of things to try:

• Does it work if you use ./gradlew runClient?
• Can you take a screenshot of your run configuration?

How do I run the mod, if I use the Gradle importer? "Minecraft Client" is not in the list.

You can use ./gradlew genIntellijRuns, or just create a new task like your screenshot above. See also the MinecraftForge docs.

That worked for me! Thanks!

Ahh, probably because you ran the idea task instead of importing directly. Really not sure what's going on then.

This two commands works perfect with the old CC. What commands do you suggest instead to make the code ready for IntelliJ?

Curious - nothing should have changed which'd cause file mounts to suddenly stop working. I Just use IntelliJ's built-in Gradle importing instead.