Question

I’m writing a script which keeps reference of some commits in a repository, but if some commits gets squashed then references become invalid. I know that there is pre-rebase hook, but no post-rebase hook, so is there a way to determine which commits get squashed together?

For example, before rebase I had this history:

cf79121 Refactor the trim_file_name method. Closes #1965.
82ed26a Updated dependencies and project versions.
8047297 Updated Node.js implementation package information.
b2b727c Added "finished" callback, which is called for each "completed" or "failed" event.

After rebase I got:

cf79121 Refactor the trim_file_name method. Closes #1965.
9b7ac26 Updated dependencies, project versions, and node.js package information.
b2b727c Added "finished" callback, which is called for each "completed" or "failed" event.

How can I find out that 82ed26a + 8047297 = 9b7ac26?

Answer 1

Unless that information is still in the reflog of the repo in which you just git squash commits,… I don’t think you would be able to get that information back.
See “How to undo a git merge squash?“.

So your script could work in the local git repo in which a squash took place, but it wouldn’t work in a clone of that same repo.

Unless a squash is systematically documented in the comments when a user does one, that information (which commits has been squashed) won’t be available.