Fatal: reference is not a tree: b8f1ebb46a91f1c634e616feb89ae34de5937e17

Hello everyone I was just going through second cohort of pioneer program . When I run cabal repl in week03 it’s giving me reference is not a tree error. Could anyone please tell me how to fix this?

Here is the error
Screenshot from 2022-11-18 18-29-51

Try a git fetch or git pull first to get latest.

Typically this kind of error means the SHA-1 is not valid so the commit history is outdated between local and remote.

I have checked in the repo and seems the commit is deleted from repo

Whelp, that is special as the entire point of source control management via a repository is so that you never lose anything ever. You can also attempt a git show or git log to search but presumably that is how you knew the commit hash was nuked via force push or something stupid. Alternately, try messaging Lars or someone in the pioneer program directly as in the past they deleted solutions in preparation for the next PPP class …