Re: [PATCH 4/4] git-commit: add a prepare-commit-msg hook

[Junio C Hamano <gitster@pobox.com>]

Paolo Bonzini <bonzini@gnu.org> writes:

> It takes two parameters.  The first is the source of the commit
> message, and can be: `message` (if a `\-m` or `\-F` option was
> given); `template` (if a `\-t` option was given or the
> configuration option `commit.template` is set); `merge` (if the
> commit is a merge or a `.git/MERGE_MSG file exists); `squash`
> (if a `.git/SQUASH_MSG file exists); or a commit id (if a
> `\-c`, `\-C` or `\--amend` option was given).  The second
> parameter if the name of the file that the commit log message.

Please do without funny mark-ups.  The commit log is not
AsciiDoc.

> The hook is not suppressed by the `\--no-verify` option.  However,
> exiting with non-zero status only aborts the commit if said option
> is not given to `git-commit`.

I do not understand why.  I do understand that you do not want
to bypass prepare-commit-msg with or without --no-verify,
because this hook is not about input validation but about input
preparation.  But I do not understand why a failure exit from it
should be treated any differently with or without --no-verify?

If you want to be strict and be safe catching a breakage in the
prepare-commit-msg hook, you should always abort.  You could
also choose to ignore.  In either case, shouldn't the validation
be left to pre-commit hook (for the tree) and commit-msg hook
(for the message, that is left after this hook)?

> While the default hook just adds a Signed-Off-By line at the bottom

It's "s/[OB]/ob/;", and ...

> of the commit messsage, the hook is more intended to build a template
> for the commit message following project standards, that the user
> can then edit or discard altogether.
>
> Signed-off-by: Paolo Bonzini <bonzini@gnu.org>

... you know it ;-)