# Fwd: Discovering the new parents in commit hooks 2 messages from 2019-07-05 to 2019-07-08. Participants: scott douglass, brian m. carlson. Thread: https://gitlist.dev/t/51438 ## scott douglass, 2019-07-05 22:01 Subject: Fwd: Discovering the new parents in commit hooks Message-ID: URL: https://gitlist.dev/e/CAOqHT5K_JZDZ1agEL4ceVdYY%3D4YYO715v%2Bj_bNbJWOoV%3DKNqQQ%40mail.gmail.com In-Reply-To: ``` Hi, I’d like to be able to discover the new parents-to-be SHA-1s during the hooks that run before a commit*. Essentially I’d like be able to distinguish the ‘git commit’ case from ‘git commit —amend’. Is there already a way to do this that I have overlooked? (I’ve read ‘man githooks’ and searched the wiki and various other places.) If not, I would propose that perhaps the hooks could be passed a GIT_PARENTS (or perhaps GIT_NEW_PARENTS) environment variable which in the ‘not amend’ case would contain the SHA-1 for HEAD and MERGE_HEAD (if appropriate) and in the ‘—amend' case would contain HEAD^@ (all of the parents of HEAD). [*] Specifically, it seems a useful thing to be able to find out in these hooks: applypatch-msg, pre-applypatch, commit-msg, prepare-commit-msg, commit-msg Thanks. ``` ## brian m. carlson, 2019-07-08 20:09 Subject: Re: Fwd: Discovering the new parents in commit hooks Message-ID: <20190708200906.GF9224@genre.crustytoothpaste.net> URL: https://gitlist.dev/e/20190708200906.GF9224%40genre.crustytoothpaste.net In-Reply-To: ``` On 2019-07-05 at 22:01:59, scott douglass wrote: > Hi, > > I’d like to be able to discover the new parents-to-be SHA-1s during > the hooks that run before a commit*. Essentially I’d like be able to > distinguish the ‘git commit’ case from ‘git commit —amend’. Is there > already a way to do this that I have overlooked? (I’ve read ‘man > githooks’ and searched the wiki and various other places.) I'm not aware of a way to distinguish this currently, although I agree having a way would be valuable. There are of course heuristic ways, but they can be fooled. > If not, I would propose that perhaps the hooks could be passed a > GIT_PARENTS (or perhaps GIT_NEW_PARENTS) environment variable which in > the ‘not amend’ case would contain the SHA-1 for HEAD and MERGE_HEAD > (if appropriate) and in the ‘—amend' case would contain HEAD^@ (all of > the parents of HEAD). I think we'd probably skip such functionality in favor of exposing whether a commit is to be amended or not and let you script the parents yourself. There are a lot of cases where one might want to know whether a commit was amended, but knowing that, you can determine the parents and anything else without much difficulty, so the amended option seems like the more general feature to implement. -- brian m. carlson: Houston, Texas, US OpenPGP: https://keybase.io/bk2204 ```