ls-refs: filter refs using namespace-stripped name

If a user fetches refs/heads/master from a repo with namespace "ns", the
remote is expected to (1) not send the real refs/heads/master, and (2)
send refs/namespaces/ns/refs/heads/master with the name
refs/heads/master. (1) indeed happens now, but not (2) - Git only sends
refs that have the user-given prefix, but it checks them against the
full name of the ref (the one starting with refs/namespaces), and not
the namespace-stripped one.

This is demonstrated by the patch in the test. Currently, it results in
"fatal: couldn't find remote ref refs/heads/master" despite both
unnamespaced and namespaced master being present. With the code change,
it produces the expected result.

Check the ref prefixes against the namespace-stripped name.

This bug was discovered through applying patches [1] that override
protocol.version to 2 in repositories when running tests, allowing us to
notice differences in behavior across different protocol versions.

[1] https://public-inbox.org/git/cover.1547677183.git.jonathantanmy@google.com/

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/ls-refs.c b/ls-refs.c
index a06f12e..7782bb0 100644
--- a/ls-refs.c
+++ b/ls-refs.c
@@ -40,7 +40,7 @@ static int send_ref(const char *refname, const struct object_id *oid,
 	const char *refname_nons = strip_namespace(refname);
 	struct strbuf refline = STRBUF_INIT;
 
-	if (!ref_match(&data->prefixes, refname))
+	if (!ref_match(&data->prefixes, refname_nons))
 		return 0;
 
 	strbuf_addf(&refline, "%s %s", oid_to_hex(oid), refname_nons);