Re: [ANNOUNCE] Git v2.8.0-rc2

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 17, 2016, 16:15 UTC
Message-ID: <xmqqio0l13nz.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <56EAC47F.6000708@drmicha.warpmail.net>

Michael J Gruber <git@drmicha.warpmail.net> writes:

> So, in short, I do believe there is a good reason for the "out of sync"
> git.pot. That doesn't make the negative side effect that I describe any
> less true, and I'm looking for ways to ammeliorate that. Something as
> easy as "make check" or "make test-lint".

Yes, I agree fully with the last sentence. I think the task probably needs two building blocks:

 - A tool to generate up-to-date git.pot contents and store into a
   given filename.

 - A tool that can be used to compare two versions of a .pot file,
   stored as two separate files in the filesystem, without the noise
   that comes from auto-generator (e.g. line numbers, the difference
   of line-wrapping the same messge).

With that, a user can (1) run the former and save the result in git.pot-before-change before making any change (2) do her work, (3) run the former again and save the result in git.pot-after-change, and (4) run the latter between these two.

This is a bit hard to drive from the Makefile, though, as our Makefile cannot assume people are using Git (they may be working off of a tarball extract to produce a one-liner patch), and there is the issue of "then how do we ensure that the user runs the former first on prestine before starting to hack so that later the result can be compared?"

But just like the version number generation, it is OK for some targets to be optional, so perhaps it is OK for this "view pot changes" task is limited to those who work on their own clone of Git. If we add that assumption, then the Makefile target for "view-pot-changes" would

 - see if untracked file git.pot-$(git rev-parse HEAD) exists (treat
   this as a build artifact, like *.o files).  If it does not exist:

  - check out HEAD to a temporary location elsewhere on the
    filesystem;

  - run the first tool and store the result in the above file.

 - run the first tool in the working tree and store the result in
   another file git.pot-now (treat this file as a build artifact,
   too).

 - run the second tool on these two git.pot files.

Add "git.pot-*" to our .gitignore file, and make sure "make clean" removes them.