I just got another feature idea, unless you have a better answer to this problem. Not that rarely, a newly added file is not checked into version control. This is tricky, since everything will keep working fine locally, so it will not be discovered (automatically) until you push. I suggest an option to auto-ignore (source) files not under version control. This way, the file would not be picked up by pants, and the issue would surface much sooner.

Interesting. I think this would personally confuse me when iterating, but I see the appeal Iiuc, CI will catch this, right? If you haven't added the files, they won't be included in CI?

Exactly.. provided you have test coverage for it cough cough 😛 And there could be clearly visible warnings in case such files are ignored, with indications to

git|hg|svn|vcs|... add

them in order for pants to pick them up.