Re: [PATCH] Add option to git-commit to allow empty log messages

From: Jeff King <peff@peff.net>
Date: Apr 6, 2010, 05:55 UTC
Message-ID: <20100406055530.GE3901@coredump.intra.peff.net>
In-Reply-To: <20100405175822.GA32083@progeny.tock>

On Mon, Apr 05, 2010 at 12:58:22PM -0500, Jonathan Nieder wrote:

Show 7 quoted lines

> > There's probably a lot of code out there doing `git commit -m"Yet
> > another revision"' from some cron job.
> 
> FWIW, I have no strong opinion about whether to add this --allow-empty-message
> option.  Maybe it would make something more convenient for someone,
> though that has to be weighed against it making it harder for everyone
> else to read the manual.

I meant to mention this in my other response: I would prefer if such an option doesn't clutter up the usage message. --allow-empty is already there, and probably doesn't need to be. "git commit -h 2>&1 | wc -l" shows a whopping 39 lines, which IMHO is too many for a short usage summary. I mean, "--no-post-rewrite", is that really one of the top-used options?

Show 7 quoted lines

> Hint:
> 
> 	parent=HEAD && : or whatever &&
> 	tree=$(git write-tree) &&
> 	printf "%s\n" message |
> 	commit=$(git commit-tree "$tree" -p "$parent") &&
> 	git update-ref refs/heads/somebranch "$commit"

In addition to the bug you mention later, you also probably want to do:

  parent=`git rev-parse --verify HEAD`
  [...]
  git update-ref \
    -m 'automated commit by tool X' \
    refs/heads/somebranch $commit $parent

which will give your reflog entry a more useful message, and will protect against simultaneous updates losing history (update-ref will make sure, while locked, that somebranch contains the $parent sha1 you wrote as part of the commit object).

And of course it still doesn't handle parentless root commits.

So doing it right really is a bit more work than just calling "git commit".

-Peff