# Re: \[PATCH\] merge: Run commit-msg hook

- From: Junio C Hamano \<hidden\>
- Date: 2016-07-26 21:07:10 
- List: git
- Page: https://ratatoskr.run/git/2016/07/7686465
- Thread: https://ratatoskr.run/git/2016/07/7686465/t.md

```text
Orgad Shaneh [ref] writes:

>> Hmm. This is not very convincing to me, as
>>
>> - if you call commit-msg in `git merge` now, why not `prepare-commit-msg`?
>
> prepare-commit-msg is already called, a few lines above this addition.

I do not see such call in contrib/example/git-merge.sh; could it be
a recent bug that it calls it?

>> - a merge is a different beast from a simple commit. That is why we have
>>   two different commands for them. A hook to edit the merge message may
>>   need to know the *second* parent commit, too, for example to generate
>>   a diffstat, or to add information about changes in an "evil commit".
>
> That is correct for a post-merge hook. Why should *message validation* differ
> between simple and merge commit?

Have you seen a typical merge commit message?  They certainly look
different to me and different rules would apply.

>> - if Gerrit is the intended user, would it not make more sense to
>>   introduce a new hook, e.g. `merge-msg` (and `prepare-merge-msg`), as you
>>   have to teach Gerrit a new trick anyway?
>
> Why is that new? Every commit in gerrit has a Change-Id footer, which is
> generated by commit-msg hook.

Hmm, I didn't know Gerrit gave Change-ID to merges.

In any case, I would think this is completely new.  Without this
change, commit-msg was not called for merges, so Gerrit wouldn't
have added Change-ID to merges with that mechanism.

A new merge-msg hook would make more sense, if we were making any
change.  I do not want to get yelled at by those who wrote their
commit-msg hooks long time ago and have happily been using them that
updated Git started calling them for their merges where their
validation logic for their single-parent commit do not apply at all.
```