Re: [Bug] commit-tree shouldn't append an extra newline to commit messages

From: Jeff King <peff@peff.net>
Date: Sep 5, 2017, 15:36 UTC
Message-ID: <20170905153636.tsmlq3wv7ztpc67z@sigill.intra.peff.net>
In-Reply-To: <CAEVs+zbbWQuM-=5d04bkpTu38Mr4PyczskNhni5K1u_nzh-2Qw@mail.gmail.com>

On Tue, Sep 05, 2017 at 11:09:01AM -0400, Ross Kabus wrote:

Show 10 quoted lines

> On Sat, Sep 2, 2017 at 4:33 AM, Jeff King <peff@peff.net> wrote:
> 
> > But I am confused by your "inconsistent with git commit porcelain"
> > comment. The porcelain git-commit definitely _does_ add a newline if one
> > isn't present (and in fact runs the whole thing through git-stripspace
> > to clean up whitespace oddities).
> 
> Ok I figured out my confusion. The repository I am working with did
> commits with "git commit --cleanup=verbatim" thus do not have a newline.
> This is why I thought there was an inconsistency.

OK, that makes more sense. Though I think even with verbatim, "-m" will still complete a line (it happens in opt_parse_m):

  $ git commit -q --allow-empty -m foo
  $ git cat-file commit HEAD | xxd
  ...
  00000090: 3034 3030 0a0a 666f 6f0a                 0400..foo.
                                  ^^
				  newline

That makes sense, since the idea of "-m" is to take a one-liner, but you would not typically provide the newline yourself via the shell.

It looks like "-F" does not do an explicit complete-line (so it would depend on --cleanup to do it normally, but in verbatim mode would not). That makes sense to me, as well (in a full file, usually you _would_ have the newline, or choose to omit it intentionally, and we should respect that). So I'd argue that "git commit -F" is doing a reasonable thing, and "commit-tree -F" should probably change to match it (because it's inconsistent, and because if anything the plumbing commit-tree should err more on the side of not touching its input than the porcelain commit command).

Show 7 quoted lines

> > So I don't think "inconsistent with git-commit" is a compelling
> > argument, unless I'm missing something.
> 
> Agreed, but now I guess I would argue that it is inconsistent because
> it lacks a "verbatim" option like git-commit has. I would like to see
> an argument like this for commit-tree but a clean way to add this option
> didn't immediately jump out at me.

I think the default behavior of reading via stdin _is_ the verbatim option. And you can choose whether or not to pipe it through git-stripspace to do more cleanup (and in fact, when git-commit was implemented as a shell script long ago, that's exactly how it was implemented). But...

> > And definitely it does not when taking the message in via stdin.
> 
> I'm not seeing this, I see commit-tree as adding a new line even via
> stdin (and the code seems to corroborate this), unless I missed something.

I'm not sure why you're seeing that. It seems verbatim to me:

  $ tree=$(git write-tree)
  $ commit=$(printf end | git commit-tree $tree)
  $ git cat-file commit $commit | xxd
  ...
  00000090: 3034 3030 0a0a 656e 64                   0400..end

-Peff