The bug

MC-121379 happens again, with errors such as

Non [a-z0-9/._-] character in path of location: namespace:worldgen/structure/.DS_Store

How to reproduce

1. Start the game with the output log enabled
2. Load a data pack that has .DS_Store files (which are common on macOS)
3. Notice the errors in the log

Expected behavior

I expected the game to exclude these hidden system files when loading data packs and resource packs, and I expected this wouldn't show errors in the log.