This mostly works, unless you’re cloning with a --depth=1.
I’ll implement a hook to call a git fetch --depth 1 {upstream} commit soon if the target cannot be found initially, otherwise we’d be stuck doing a partial/full clone which is not ideal. We should be able to fetch what we need.
Edit: Updated here:
https://github.com/discourse/discourse/commit/787ad7d84ddb74a91e851c04ad13f7dab29ee96a
I’ve backported this one to Beta and Stable as well - so we should be able to pin even with shallow clones now.