Please note I did make sure to be able to download everything, but it is still not working.

Both “gradlew build” and “gradlew setupDecompWorkspace” will result in this Error.

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':reobf'.
> java.io.FileNotFoundException: ~/projects/minecraft/et-futurum-requiem/build/tmp/reobf/mixins.srg (No such file or directory)

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 8s
13 actionable tasks: 5 executed, 8 up-to-date

I can only close with a comment, but if i left the comment BEFORE closing i cant really close without leaving YET ANOTHER comment. That was my issue lol.

I have cleaned my build folder (I did not delete .gitignore) and tried both commands. setupdecompworkspace succeeds, and gradlew build also succeeds, the latter of which generates the mixins.srg file.

No one else has run into this issue so I'm wondering if your workspace possibly ran into a hiccup along the way. What happens if you delete and re-clone the repository?

Clearing out the build directory fixed it, thanks.

Edit: Sorry for notification spam, but apparently i cant close as completed as a STANDALONE action on the github web page...

Weird, for me I can do that. What do you see? We can use this issue here as a quick test if you want.