fetch: do not ask for HEAD unnecessarily

In 3f763ddf28 (fetch: set remote/HEAD if it does not exist,
2024-11-22), git-fetch learned to opportunistically set $REMOTE/HEAD
when fetching by always asking for remote HEAD, in the hope that it
will help setting refs/remotes/<name>/HEAD if missing.

But it is not needed to always ask for remote HEAD.  When we are
fetching from a remote, for which we have remote-tracking branches,
we do need to know about HEAD.  But if we are doing one-shot fetch,
e.g.,

  $ git fetch --tags https://github.com/git/git

we do not even know what sub-hierarchy of refs/remotes/<remote>/
we need to adjust the remote HEAD for.  There is no need to ask for
HEAD in such a case.

Incidentally, because the unconditional request to list "HEAD"
affected the number of ref-prefixes requested in the ls-remote
request, this affected how the requests for tags are added to the
same ls-remote request, breaking "git fetch --tags $URL" performed
against a URL that is not configured as a remote.

Reported-by: Josh Steadmon <steadmon@google.com>
[jc: tests are also borrowed from Josh's patch]
Signed-off-by: Junio C Hamano <gitster@pobox.com>
maint
Junio C Hamano 2024-12-06 17:08:00 +09:00
parent e02082c7f8
commit 6c915c3f85
2 changed files with 36 additions and 1 deletions

View File

@ -1643,6 +1643,21 @@ cleanup:
return result;
}

static int uses_remote_tracking(struct transport *transport, struct refspec *rs)
{
if (!remote_is_configured(transport->remote, 0))
return 0;

if (!rs->nr)
rs = &transport->remote->fetch;

for (int i = 0; i < rs->nr; i++)
if (rs->items[i].dst)
return 1;

return 0;
}

static int do_fetch(struct transport *transport,
struct refspec *rs,
const struct fetch_config *config)
@ -1712,7 +1727,10 @@ static int do_fetch(struct transport *transport,
"refs/tags/");
}

strvec_push(&transport_ls_refs_options.ref_prefixes, "HEAD");
if (uses_remote_tracking(transport, rs)) {
must_list_refs = 1;
strvec_push(&transport_ls_refs_options.ref_prefixes, "HEAD");
}

if (must_list_refs) {
trace2_region_enter("fetch", "remote_refs", the_repository);

View File

@ -189,6 +189,23 @@ test_expect_success 'fetch --prune --tags with refspec prunes based on refspec'
git rev-parse sometag
'

test_expect_success 'fetch --tags gets tags even without a configured remote' '
REMOTE="$(pwd)/test_tag_1" &&
git init test_tag_1 &&
(
cd test_tag_1 &&
test_commit foo
) &&
git init test_tag_2 &&
(
cd test_tag_2 &&
git fetch --tags "file://$REMOTE" &&
echo "foo" >expect &&
git tag >actual &&
test_cmp expect actual
)
'

test_expect_success REFFILES 'fetch --prune fails to delete branches' '
cd "$D" &&
git clone . prune-fail &&