[PATCH] ls-refs: filter refs based on non-namespace name

[Jonathan Tan <jonathantanmy@google.com>]

Protocol v2 allows for filtering of ref advertisement based on a
client-given name prefix, but inclusion/exclusion is determined based on
the non-namespace-stripped version (e.g. matching a ref prefix of
"refs/heads" against "refs/namespaces/my-namespace/refs/heads/master")
instead of the namespace-stripped version, which is the one that the
user actually sees.

Determine inclusion/exclusion based on the namespace-stripped version.

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>
---
Another bug discovered through GIT_TEST_PROTOCOL_VERSION.

If the patches in [1] above are merged with this patch, a test that
previously failed on GIT_TEST_PROTOCOL_VERSION=2 now passes.

I'm not sure of the relevance of the last paragraph and the "[1]" in the
commit message - feel free to remove it. Since the relevant patches are
not merged yet, the e-mails are probably the best reference, and I have
tried to summarize what they do concisely.
---
 ls-refs.c            |  2 +-
 t/t5701-git-serve.sh | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/ls-refs.c b/ls-refs.c
index a06f12eca8..7782bb054b 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);
diff --git a/t/t5701-git-serve.sh b/t/t5701-git-serve.sh
index ae79c6bbc0..ec13064ecd 100755
--- a/t/t5701-git-serve.sh
+++ b/t/t5701-git-serve.sh
@@ -112,6 +112,27 @@ test_expect_success 'basic ref-prefixes' '
 	test_cmp expect actual
 '
 
+test_expect_success 'ref prefix with namespaced repository' '
+	# Create a namespaced ref
+	git update-ref refs/namespaces/ns/refs/heads/master "$(git rev-parse refs/tags/one)" &&
+
+	test-tool pkt-line pack >in <<-EOF &&
+	command=ls-refs
+	0001
+	ref-prefix refs/heads/master
+	0000
+	EOF
+
+	cat >expect <<-EOF &&
+	$(git rev-parse refs/tags/one) refs/heads/master
+	0000
+	EOF
+
+	GIT_NAMESPACE=ns git serve --stateless-rpc <in >out &&
+	test-tool pkt-line unpack <out >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'refs/heads prefix' '
 	test-tool pkt-line pack >in <<-EOF &&
 	command=ls-refs
-- 
2.19.0.271.gfe8321ec05.dirty