When cloning an empty repository served by standard git, "git clone" produces
the following reassuring message:
$ git clone git://localhost/tmp/empty
Cloning into 'empty'...
warning: You appear to have cloned an empty repository.
Checking connectivity... done.
Meanwhile when cloning an empty repository served by JGit, the output is more
haphazard:
$ git clone git://localhost/tmp/empty
Cloning into 'empty'...
Checking connectivity... done.
warning: remote HEAD refers to nonexistent ref, unable to checkout.
This is a common command to run immediately after creating a remote repository
as preparation for adding content to populate it and pushing. The warning is
confusing and needlessly worrying.
The cause is that, since v3.1.0.201309270735-rc1~22 (Advertise capabilities
with no refs in upload service., 2013-08-08), JGit's ref advertisement includes
a ref named capabilities^{} to advertise its capabilities on (following the
specification in pack-protocol.txt), while git's ref advertisement is empty in
this case. This allows the client to learn about the server's capabilities and
is needed, for example, for fetch-by-sha1 to work when no refs are advertised.
This also affects "ls-remote". For example, against an empty repository served
by JGit:
$ git ls-remote git://localhost/tmp/empty
0000000000000000000000000000000000000000 capabilities^{}
Git advertises the same capabilities^{} ref in its ref advertisement for push
but since it never did so for fetch, the client didn't need to handle this
case. Handle it.
Signed-off-by: Jonathan Tan <jonathantanmy@xxxxxxxxxx>
---
connect.c | 14 ++++++++++++++
t/t5512-ls-remote.sh | 40 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 54 insertions(+)
diff --git a/connect.c b/connect.c
index 0c01a49..7224b5e 100644
--- a/connect.c
+++ b/connect.c
@@ -123,6 +123,7 @@ struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
* response does not necessarily mean an ACL problem, though.
*/
int saw_response;
+ int got_dummy_ref_with_capabilities_declaration = 0;
*list = NULL;
for (saw_response = 0; ; saw_response = 1) {
@@ -172,8 +173,21 @@ struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
continue;
}
+ if (!strcmp(name, "capabilities^{}")) {
+ if (saw_response)
+ die("protocol error: unexpected capabilities^{}");
+ if (got_dummy_ref_with_capabilities_declaration)
+ die("protocol error: multiple capabilities^{}");
+ got_dummy_ref_with_capabilities_declaration = 1;
+ continue;
+ }
+
if (!check_ref(name, flags))
continue;
+
+ if (got_dummy_ref_with_capabilities_declaration)
+ die("protocol error: unexpected ref after capabilities^{}");
+
ref = alloc_ref(buffer + GIT_SHA1_HEXSZ + 1);
oidcpy(&ref->old_oid, &old_oid);
*list = ref;
diff --git a/t/t5512-ls-remote.sh b/t/t5512-ls-remote.sh
index 819b9dd..befdfee 100755
--- a/t/t5512-ls-remote.sh
+++ b/t/t5512-ls-remote.sh
@@ -207,5 +207,45 @@ test_expect_success 'ls-remote --symref omits filtered-out matches' '
test_cmp expect actual
'
+test_lazy_prereq GIT_DAEMON '
+ test_tristate GIT_TEST_GIT_DAEMON &&
+ test "$GIT_TEST_GIT_DAEMON" != false
+'
+
+# This test spawns a daemon, so run it only if the user would be OK with
+# testing with git-daemon.
+test_expect_success PIPE,JGIT,GIT_DAEMON 'indicate no refs in standards-compliant empty remote' '
+ JGIT_DAEMON_PORT=${JGIT_DAEMON_PORT-${this_test#t}} &&
+ JGIT_DAEMON_PID= &&
+ git init --bare empty.git &&
+ >empty.git/git-daemon-export-ok &&
+ mkfifo jgit_daemon_output &&
+ {
+ jgit daemon --port="$JGIT_DAEMON_PORT" . >jgit_daemon_output &
+ JGIT_DAEMON_PID=$!
+ } &&
+ test_when_finished kill "$JGIT_DAEMON_PID" &&
+ {
+ read line &&
+ case $line in
+ Exporting*)
+ ;;
+ *)
+ echo "Expected: Exporting" &&
+ false;;
+ esac &&
+ read line &&
+ case $line in
+ "Listening on"*)
+ ;;
+ *)
+ echo "Expected: Listening on" &&
+ false;;
+ esac
+ } <jgit_daemon_output &&
+ # --exit-code asks the command to exit with 2 when no
+ # matching refs are found.
+ test_expect_code 2 git ls-remote --exit-code git://localhost:$JGIT_DAEMON_PORT/empty.git
+'
test_done
--
2.8.0.rc3.226.g39d4020