client: add get_refs method for just ref discovery

dulwich/client.py

@@ -249,6 +249,13 @@ class GitClient(object):
         """
         raise NotImplementedError(self.fetch_pack)
 
+    def get_refs(self, path):
+        """Retrieve the current refs from a git smart server.
+
+        :param path: Path to the repo to fetch from.
+        """
+        raise NotImplementedError(self.get_refs)
+
     def _parse_status_report(self, proto):
         unpack = proto.read_pkt_line().strip()
         if unpack != b'unpack ok':
@@ -553,6 +560,14 @@ class TraditionalGitClient(GitClient):
                 proto, negotiated_capabilities, graph_walker, pack_data, progress)
             return refs
 
+    def get_refs(self, path):
+        """Retrieve the current refs from a git smart server."""
+        # stock `git ls-remote` uses upload-pack
+        proto, _ = self._connect(b'upload-pack', path)
+        with proto:
+            refs, _ = read_pkt_refs(proto)
+            return refs
+
     def archive(self, path, committish, write_data, progress=None,
                 write_error=None):
         proto, can_read = self._connect(b'upload-archive', path)
@@ -780,6 +795,13 @@ class LocalGitClient(GitClient):
                 return
             write_pack_objects(ProtocolFile(None, pack_data), objects_iter)
 
+    def get_refs(self, path):
+        """Retrieve the current refs from a git smart server."""
+        from dulwich.repo import Repo
+
+        with closing(Repo(path)) as target:
+            return target.get_refs()
+
 
 # What Git client to use for local access
 default_local_git_client_cls = LocalGitClient
@@ -1134,6 +1156,13 @@ class HttpGitClient(GitClient):
         finally:
             resp.close()
 
+    def get_refs(self, path):
+        """Retrieve the current refs from a git smart server."""
+        url = self._get_url(path)
+        refs, _ = self._discover_references(
+            b"git-upload-pack", url)
+        return refs
+
 
 def get_transport_and_path_from_url(url, config=None, **kwargs):
     """Obtain a git client from a URL.

dulwich/tests/compat/test_client.py

@@ -254,6 +254,14 @@ class DulwichClientTestBase(object):
             c.send_pack(self._build_path('/dest'), lambda _: sendrefs, gen_pack)
             self.assertFalse(b"refs/heads/abranch" in dest.refs)
 
+    def test_get_refs(self):
+        c = self._client()
+        refs = c.get_refs(self._build_path('/server_new.export'))
+
+        repo_dir = os.path.join(self.gitroot, 'server_new.export')
+        with closing(repo.Repo(repo_dir)) as dest:
+            self.assertDictEqual(dest.refs.as_dict(), refs)
+
 
 class DulwichTCPClientTest(CompatTestCase, DulwichClientTestBase):
 

dulwich/tests/test_client.py

@@ -627,6 +627,14 @@ class LocalGitClientTests(TestCase):
         with closing(Repo.init_bare(target_path)) as target:
             self.send_and_verify(b"master", local, target)
 
+    def test_get_refs(self):
+        local = open_repo('refs.git')
+        self.addCleanup(tear_down_repo, local)
+
+        client = LocalGitClient()
+        refs = client.get_refs(local.path)
+        self.assertDictEqual(local.refs.as_dict(), refs)
+
     def send_and_verify(self, branch, local, target):
         client = LocalGitClient()
         ref_name = b"refs/heads/" + branch