clone: support unusual remote ref configurations

When cloning a branchless and tagless but not refless remote using
protocol v0 or v1, Git calls transport_fetch_refs() with an empty ref
list. This makes the clone fail with the message "remote transport
reported error".

Git should have refrained from calling transport_fetch_refs(), just like
it does in the case that the remote is refless. Therefore, teach Git to
do this.

In protocol v2, this does not happen because the client passes
ref-prefix arguments that filter out non-branches and non-tags in the
ref advertisement, making the remote appear empty.

Note that this bug concerns logic in builtin/clone.c and only affects
cloning, not fetching.

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

diff --git a/builtin/clone.c b/builtin/clone.c
index fb377b27657c4048a04c85ddb82e15a950db5a7d..f4dc4985128f4434f6fc7a352a50c2f955641772 100644 (file)
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -862,7 +862,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
        const struct ref *refs, *remote_head;
        struct ref *remote_head_points_at = NULL;
        const struct ref *our_head_points_at;
-       struct ref *mapped_refs;
+       struct ref *mapped_refs = NULL;
        const struct ref *ref;
        struct strbuf key = STRBUF_INIT;
        struct strbuf branch_top = STRBUF_INIT, reflog_msg = STRBUF_INIT;
@@ -1184,7 +1184,10 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 
        refs = transport_get_remote_refs(transport, &transport_ls_refs_options);
 
-       if (refs) {
+       if (refs)
+               mapped_refs = wanted_peer_refs(refs, &remote->fetch);
+
+       if (mapped_refs) {
                int hash_algo = hash_algo_by_ptr(transport_get_hash_algo(transport));
 
                /*
@@ -1193,8 +1196,6 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
                 */
                initialize_repository_version(hash_algo, 1);
                repo_set_hash_algo(the_repository, hash_algo);
-
-               mapped_refs = wanted_peer_refs(refs, &remote->fetch);
                /*
                 * transport_get_remote_refs() may return refs with null sha-1
                 * in mapped_refs (see struct transport->get_refs_list
@@ -1240,7 +1241,6 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
                                        option_branch, remote_name);
 
                warning(_("You appear to have cloned an empty repository."));
-               mapped_refs = NULL;
                our_head_points_at = NULL;
                remote_head_points_at = NULL;
                remote_head = NULL;
@@ -1271,7 +1271,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 
        if (is_local)
                clone_local(path, git_dir);
-       else if (refs && complete_refs_before_fetch) {
+       else if (mapped_refs && complete_refs_before_fetch) {
                if (transport_fetch_refs(transport, mapped_refs))
                        die(_("remote transport reported error"));
        }

diff --git a/t/t5700-protocol-v1.sh b/t/t5700-protocol-v1.sh
index 468bd3e13e1e7d695c95dd06c201279d94ec00ef..6c8d4c6cf1c8e0f98e2a6cccfec798c19b1954a0 100755 (executable)
--- a/t/t5700-protocol-v1.sh
+++ b/t/t5700-protocol-v1.sh
@@ -149,6 +149,21 @@ test_expect_success 'push with file:// using protocol v1' '
        grep "push< version 1" log
 '
 
+test_expect_success 'cloning branchless tagless but not refless remote' '
+       rm -rf server client &&
+
+       git -c init.defaultbranch=main init server &&
+       echo foo >server/foo.txt &&
+       git -C server add foo.txt &&
+       git -C server commit -m "message" &&
+       git -C server update-ref refs/notbranch/alsonottag HEAD &&
+       git -C server checkout --detach &&
+       git -C server branch -D main &&
+       git -C server symbolic-ref HEAD refs/heads/nonexistentbranch &&
+
+       git -c protocol.version=1 clone "file://$(pwd)/server" client
+'
+
 # Test protocol v1 with 'ssh://' transport
 #
 test_expect_success 'setup ssh wrapper' '