I'm noticing that my OSX workstation isn't playing happily with Minecraft because it is a case sensitive filesystem.
For example, when loading the language file, it finally gets to FolderResourcePack.validatePath, it hits this line:
>>> return s.endsWith(p_191384_1_);
Looking at a debugger, here are the values of s and p_19blah
/Users/<redacted>/src/forge/bin/assets/konigsmod/lang/en_US.lang
assets/konigsmod/lang/en_us.lang
So because their cases do not match, the path is not valid.
But it's not just there, I have a file a json file that has the same problem, because I describe my items in mixedCase.
Is it possible you could replace s.endsWith(p_191384_1_) with s.toLowerCase().endsWith(p_191384_1_1.toLowerCase());? That's not i18n friendly, but if the system already deals with encodings, it gets simpler.
Why does that check even exist, anyway?
In the meantime, I plan to switch my resource names to lowercase. Hopefully that'll help.
Thanks,
Robert