Re: [PATCH v2] refspec: make @ a synonym of HEAD

From: Felipe Contreras <felipe.contreras@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Git <git@vger.kernel.org>, Jeff King <peff@peff.net>,
	Brandon Williams <bwilliams.eng@gmail.com>,
	Jacob Keller <jacob.keller@gmail.com>,
	Tomo Krajina <tkrajina@gmail.com>
Subject: Re: [PATCH v2] refspec: make @ a synonym of HEAD
Date: Wed, 25 Nov 2020 17:48:29 -0600	[thread overview]
Message-ID: <CAMP44s2cpPgg55XHTr=cRqRcrMOkU=qcrM=RpWYwVJJdd9V4JA@mail.gmail.com> (raw)
In-Reply-To: <xmqq360ygq2g.fsf@gitster.c.googlers.com>

On Tue, Nov 24, 2020 at 7:53 PM Junio C Hamano <gitster@pobox.com> wrote:
>
> Felipe Contreras <felipe.contreras@gmail.com> writes:
>
> > On Tue, Nov 24, 2020 at 6:37 PM Junio C Hamano <gitster@pobox.com> wrote:
> >> Felipe Contreras <felipe.contreras@gmail.com> writes:
> >
> >> > +test_expect_success 'push with @' '
> >> > +
> >> > +     mk_test testrepo heads/master &&
> >> > +     git checkout master &&
> >> > +     git push testrepo @ &&
> >> > +     check_push_result testrepo $the_commit heads/master
> >> > +
> >> > +'
> >>
> >> This is OK, but shouldn't this be placed before the tests with
> >> various configuration?  Something along the lines of the attached,
> >> but with the body of the loop properly reindented, would also give
> >> us a better test coverage at the same time.
> >
> > I don't see much value in those tests, since I don't see how if one
> > passes another one would fail. But I guess it cannot hurt.
>
> That can only be said based on the knowledge of the implementation
> detail of the code immediately after this patch gets applied.  Any
> future change to the code for whatever reason (e.g. refactoring) can
> make the current assumption invalid.

It's not just the current implementation of the code; it's any
implementation of the code (in my opinion).

> As the proposed log message says,
>
>     Since commit 9ba89f484e git learned how to push to a remote branch using
>     the source @, for example:
>
>       git push origin @:$dst
>
>     However, if the right-hand side is missing, the push fails:
>
>       git push origin @
>
> we care about both of these forms working, not just the singleton
> form, so it is not just "not hurt", but is actively a good thing, to
> protect both forms from future breakage.  After all, that is why we
> have tests.

Both forms were already tested.

What you suggested adds three more tests: 3. +@ form, 4. @ not present
on the remote, 5. @ in remote.*.push. If the first two pass, I cannot
see any implementation that would fail the other three (okay, maybe
the +@ one).

Anyway, I had to improve the current tests to make your suggestion
work, and what once was a single simple patch now became a series that
is mostly shuffling around test code. At some point the aphorism
"don't let the perfect be the enemy of the good" has to apply though.

Cheers.

-- 
Felipe Contreras