Re: [PATCH 1/7] shorten_unambiguous_ref(): Allow shortening refs/remotes/origin/HEAD to origin

From: Junio C Hamano <gitster@pobox.com>
Date: May 7, 2013, 21:31 UTC
Message-ID: <7vy5bqiij3.fsf@alter.siamese.dyndns.org>
In-Reply-To: <CALKQrgcoz-+5Kb-Y1Ui9LhE=+pvcRUdAS+iRWXAfsYnV6+k34w@mail.gmail.com>

Johan Herland <johan@herland.net> writes:

Show 18 quoted lines

> On Mon, May 6, 2013 at 7:52 PM, Junio C Hamano <gitster@pobox.com> wrote:
>> Johan Herland <johan@herland.net> writes:
>>
>>> ... there is AFAICS _no_ way for sscanf() - having
>>> already done one or more format extractions - to indicate to its caller
>>> that the input fails to match the trailing part of the format string.
>>
>> Yeah, we can detect when we did not have enough, but we cannot tell
>> where it stopped matching.
>>
>> It is interesting that this bug has stayed so long with us, which
>> may indicate that nobody actually uses the feature at all.
>
> I don't know if people really care about whether
> "refs/remotes/origin/HEAD" shortens to "origin/HEAD" or "origin". I'm
> guessing that people _do_ depend on the reverse - having "origin"
> expand into "refs/remotes/origin/HEAD", so we probably cannot rip out
> the "refs/remotes/%.*s/HEAD" rule altogether...

Oh, no doubt about that reverse conversion.

The real reason nobody cared about refs/remotes/origin/HEAD is that nobody sane has anything but non-symbolic ref there. Your t1514 does this:

	...
	git update-ref refs/master master_d &&
	test_commit master_e
	git update-ref refs/remotes/origin/HEAD master_e &&
	...

Nowhere in the set-up sequence, you see anything that does

	git symbolic-ref refs/remotes/origin/HEAD refs/remotes/origin/master

or any other branch we copied from the remote.

And the shortening is done after dereferencing the synbolic ref. Because of this, refs/remotes/origin/HEAD usually resolves to origin/master, not origin.

 t/t1514-rev-parse-shorten-unambiguous-ref.sh | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/t/t1514-rev-parse-shorten-unambiguous-ref.sh b/t/t1514-rev-parse-shorten-unambiguous-ref.sh
index fd87ce3..556ad16 100755
--- a/t/t1514-rev-parse-shorten-unambiguous-ref.sh
+++ b/t/t1514-rev-parse-shorten-unambiguous-ref.sh
@@ -76,4 +76,11 @@ test_expect_success 'shortening refnames in loose mode' '
 	test_shortname refs/tags/master loose tags/master master_c
 '
 
+test_expect_success 'shortening is done after dereferencing a symref' '
+	git update-ref refs/remotes/frotz/master master_e &&
+	git symbolic-ref refs/remotes/frotz/HEAD refs/remotes/frotz/master &&
+	test_shortname refs/remotes/frotz/HEAD strict frotz/master master_e &&
+	test_shortname refs/remotes/frotz/HEAD loose frotz/master master_e
+'
+
 test_done