Also, do we want to allow

PathGlobsAndRoot

to work with the asynchronous rules API? We need to keep it for tests to continue working. It does seem like a useful intrinsic, generally. Maybe we’d want to discourage it for arguments of hermiticity and reproducibility, but also Everyone Is An Adult

would avoid it unless there is a usecase… the easiest way to avoid file collisions is to use snapshots that are rooted at the buildroot, so would be good to avoid implying that it’s necessary to use relative paths in general

Okay. Sounds good. I’m gonna move PathGlobsAndRoot out of fs.py then so that it’s not in the public API