Re: Keep original author with git merge --squash?

From: Junio C Hamano <gitster@pobox.com>
Date: Feb 12, 2015, 21:23 UTC
Message-ID: <xmqq8ug2rfi2.fsf@gitster.dls.corp.google.com>
In-Reply-To: <CAN7QDoLKFBCJpFa+QL8dPQtwyAyDNt-ck_sNJ3fS+vTrK_Lg9w@mail.gmail.com>

David Glasser <glasser@davidglasser.net> writes:

Show 5 quoted lines

> Well, using -c appears to override SQUASH_MSG entirely; it replaces
> the message as well as the author.  Often I do want to make my own
> message based on all the messages provided by the submitter.  (And
> typically the branch's tip is the least useful message anyway: it's
> usually something like "respond to code review".)

I wonder if there is a bug in the workflow. Isn't the contributor forcing more work to the integrator that way and making it a responsibility of the integrator to squash multiple commits into one, instead of asking a cleaned-up branch to be merged in the first place? It is a key to keep your project scalable to push as much work out of the integrator's plate to the contributors' plates.

But that is an unrelated tangent. Among the ideas floated in the thread, I tend to like something like what Peff mentioned earlier.

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> I assume you are already munging in your editor the template provided by
> "git commit" after the squash? What would be really nice, IMHO, is if
> there was a way to set the author during that edit (e.g., by moving one
> of the "Author:" lines to the top of the file). That would cover your
> use case, I think, and would also be useful in general.

I don't know if the exact solution Peff mentioned is good [*1*], but being able to do an equivalent of setting --author="<author>" and "--date=<date>" from the command line inside the log message editor would be a huge win.

[Footnote]

*1* You would see

	gostak: do not distim doshes unconditionally

	Usually it is a good idea to let gostak distim doshes,
        but it should cause the program segfault when there is
        no doshes to be distimmed.  Detect this case and error
        out.

	Signed-off-by: David Glasser <glasser@davidglasser.net>

        # Please enter the commit message ...
        #
        # Author:    David Glasser <glasser@davidglasser.net>
        # Date:      Thu, 12 Feb 2015 04:28:24 -0500
        # ...

when you start "git commit --amend" or "git merge --squash", and the proposal, as I understand it, is to allow you to do this:

        From: David Glasser <glasser@davidglasser.net>
        Date: Thu, 12 Feb 2015 04:28:24 -0500

	gostak: do not distim doshes unconditionally

	Usually it is a good idea to let gostak distim doshes,
        but it should cause the program segfault when there is
        no doshes to be distimmed.  Detect this case and error
        out.

	Signed-off-by: David Glasser <glasser@davidglasser.net>

        # Please enter the commit message ...
        #
        # ...

which is the same format of the _body_ of the message "git am" would take. The reason I am not so sure about such a change is that having to move and edit things would be error prone. Some may forget to do s/Author:/From:/ and we would end up having to support both. Some existing commit may validly have lines that begin with these tokens ("git am" does not have such a problem because it is not the underlying "git commit" or "git commit-tree" that interprets these in-body headers). Some users may forget to leave a blank line between the in-body headers and the subject line.

I suspect that it _might_ work better if we always look for the pair of "# Author: " and "# Date:" lines (taking the commentchar setting in to account, of course) immediately at the beginning of the trailing comment block, and if exists, use that to override the authorship identity. If the user does not do anything when running "git commit --amend", the resulting commit will get the original authorship. If the user strips all the lines in the trailing comment block, we would do the same thing as we have always done and retain the original authorship.

I dunno.