Re: [Bug] commit cleanup does not happen during autosquash rebase
- From
- Phillip Wood <phillip.wood123@gmail.com>
- Date
- Aug 18, 2025, 15:14 UTC
- Message-ID
- <63e7901f-4210-438e-9389-8117d5fb83b6@gmail.com>
- In-Reply-To
- <CA+itcS3DxbgpFy2aPRvHQvTAYE=dU0kfeDdidVwWLU=rBAWR4w@mail.gmail.com>
Hi Simon
On 13/08/2025 12:39, Simon Cheng wrote:
Show 13 quoted lines
> > What did you do before the bug happened? (Steps to reproduce your issue) > > 1. Initialize a git repo with `git init` > 2. Install a custom `prepare-commit-msg` hook that injects some comments > - Intention: inject the output of `git log --oneline -n10` during > interactive commit, so I can see past commits > 3. Run `git config commit.cleanup strip` > - Intention: strip the injected comments too in non-interactive mode > (e.g. `git cherry-pick` & `git rebase`) > 4. Run `touch foo && git add -A && git commit -m "Initial commit"` > 5. Run `touch bar && git add -A && git commit --fixup=@` > 6. Run `git rebase --root --autosquash`
Thanks for providing a simple way to reproduce this
Show 9 quoted lines
> What did you expect to happen? (Expected behavior) > > Git would perform the autosquash, while keeping the commit message of > the squash target unchanged. > > What happened instead? (Actual behavior) > > Git performed the autosquash, but the commit message of the squash > target is now clobbered with my injected comments.
It looks like this stems from f7d42ceec52 (rebase -i: do leave commit message intact in fixup! chains, 2021-01-28) which was added in response to a bug report[1]. That commit switched from always cleaning up the fixup message to never cleaning it up. I wonder if instead we should be respecting the user's commit.cleanup setting. The commit message says that should not respect commit.cleanup because we want to use the message verbatim but that is not what we do with "pick" commands which respect commit.cleanup if it is set. Given that we call the prepare-commit-msg hook we cannot be sure that we're reusing the original commit message verbatim anyway so I think we should probably change "fixup" commands to use the same cleanup flags as "pick" commands.
I'm going to be off the list for a week from tomorrow but I'll try and look at this again when I'm back if no one else has picked it up in the meantime.
Thanks
Phillip
[1] https://lore.kernel.org/git/CANVGpwZGbzYLMeMze64e_OU9p3bjyEgzC5thmNBr6LttBt+YGw@mail.gmail.com/
Show 46 quoted lines
> What's different between what you expected and what actually happened?
>
> I expected commit cleanup to happen during the autosquash. It seems
> like that didn't happen.
>
> Anything else you want to add:
>
> Here is my `prepare-commit-msg` script. But I expect this issue to be
> replicable with anything that injects comments.
>
> ```
> #!/usr/bin/env bash
> {
> echo '# Last 10 commits:'
> git log --oneline -n 10 --decorate=short | sed 's/^/# /'
> echo '#'
> } >> "$1"
> ```
>
> Please review the rest of the bug report below.
> You can delete any lines you don't wish to share.
>
>
> [System Info]
> git version:
> git version 2.50.1
> cpu: x86_64
> built from commit: d82adb61ba2fd11d8f2587fca1b6bd7925ce4044
> sizeof-long: 8
> sizeof-size_t: 8
> shell-path: /bin/sh
> libcurl: 8.14.1
> OpenSSL: OpenSSL 3.5.1 1 Jul 2025
> zlib-ng: 2.2.4
> SHA-1: SHA1_DC
> SHA-256: SHA256_BLK
> uname: Linux 6.12.41-1-lts #1 SMP PREEMPT_DYNAMIC Fri, 01 Aug 2025
> 20:42:03 +0000 x86_64
> compiler info: gnuc: 15.1
> libc info: glibc: 2.42
> $SHELL (typically, interactive shell): /bin/bash
>
>
> [Enabled Hooks]
> prepare-commit-msg
>