Re: What's cooking in git.git (Oct 2016, #03; Tue, 11)

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Oct 16, 2016, 08:31 UTC
Message-ID: <alpine.DEB.2.20.1610151020480.197091@virtualbox>
In-Reply-To: <xmqqzim6zzc7.fsf@gitster.mtv.corp.google.com>

Hi Junio,

On Fri, 14 Oct 2016, Junio C Hamano wrote:

Show 22 quoted lines

> Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
> 
> >> >> * sb/submodule-ignore-trailing-slash (2016-10-10) 2 commits
> >> >>   (merged to 'next' on 2016-10-11 at e37425ed17)
> >> >>  + submodule: ignore trailing slash in relative url
> >> >>  + submodule: ignore trailing slash on superproject URL
> >> >>
> >> >>  A minor regression fix for "git submodule".
> >> >>
> >> >>  Will merge to 'master'.
> >> >
> >> > Going by the bug report, this *may* be more than
> >> > minor and worth merging down to maint as well, eventually.
> >> 
> >> The topic was forked at a reasonably old commit so that it can be
> >> merged as far down to maint-2.9 if we wanted to.  Which means the
> >> regression was fairly old and fix is not all that urgent as well.
> >
> > And if you merge it to `master` and `maint`,...
> 
> I'll mark it as "wait for follow-up fix" in whats-cooking.txt (on
> 'todo' branch) to remind myself not to merge it yet.

May I request your guidance as to your preference how to proceed? Here is the problem: Stefan's fix uncovered a bug in the way Git for Windows' Bash hands off "Unix" paths to real Windows programs, such as `git submodule-helper`: trailing `/.` gets truncated to `/`.

That is, when passing `/c/test/.` to the helper, what arrives is actually `C:/test/`. So the helper, being expected to cut off trailing slashes, cuts it off because it does not see the dot.

Note: when passing URLs (`https://repos.com/mine/.`) or when passing
Windows paths (`C:/test/.`), the helper *will* see the dot, and all is
fine.

Unfortunately the behavior of the MSYS2 Bash cannot be altered in that respect because existing build workflows *depend* on the current behavior.

Please note we did not have that problem previously, as the helper was a shell script and therefore stayed in the POSIX-emulated realm, no POSIX->Windows path translation necessary.

Now, we have two tests in t0060 that try to catch changes in this particular scenario, verifying that only the dots are cut off of paths like `/a/b/c/.`.

Given that we cannot modify MSYS2 to appease those tests (because we would break many more important things), and given that you can easily work around this by using paths native to Windows when using Git interactively (which the tests cannot do because they target Linux), I am inclined to change the tests.

Here are the options I see:

A) remove the tests in question

B) mark them as !MINGW instead

C) change just those two tests from using `$PWD` (pseudo-Unix path) to
  `$(pwd)` (native path)

I would like to hear your feedback about your preference, but not without priming you a little bit by detailing my current opinion on the matter:

While I think B) would be the easiest to read, C) would document the expected behavior better. A) would feel to me like shrugging, i.e. the lazy, wrong thing to do.

What do you think? Dscho