`git rev-list` failed when updating stack about ghstack

[amyreese]

Looks like this was because my .git/config for that repo was only set up to sync the main branch, for reasons I don't understand:

[remote "upstream"]
    url = [email protected]:Instagram/LibCST.git
    fetch = +refs/heads/main:refs/remotes/upstream/main
    gh-resolved = base

Replacing main with * on both sides of the fetch option resolved this issue. Perhaps this is something we should validate somewhere in ghstack?

[amyreese]

I believe this is also why I was encountering errors with this project — it had a similar git config. I think this might be the way that the gh tool clones from forked repos, with the expectation that upstream branches don't matter. Then trying to use ghstack with that git config blows up.

I'll look at adding a simple check for this config, and submit a PR to at least call it out and probably abort early.

[ezyang]

Aha! The best fix is to manually specify an appropriate refspec when we fetch. Do you think you know how to construct that PR?

[amyreese]

I'll see what I can figure out tomorrow. I'll have to pay closer attention to what's happening with the git commands. 😅