git: make use of pygit2 more

- detect if is a good git repo
- few fixes and cleanups for pygrack

vcsserver/remote/git.py

@@ -186,19 +186,25 b' class GitRemote(RemoteBase):'
         region = self._region(wire)
 
         @region.conditional_cache_on_arguments(condition=cache_on)
-        def _assert_correct_path(_context_uid, _repo_id):
+        def _assert_correct_path(_context_uid, _repo_id, fast_check):
+            if fast_check:
+                path = safe_str(wire['path'])
+                if pygit2.discover_repository(path):
+                    return True
+                return False
+            else:
             try:
                 repo_init = self._factory.repo_libgit2(wire)
-                with repo_init as repo:
+                    with repo_init:
                     pass
             except pygit2.GitError:
                 path = wire.get('path')
                 tb = traceback.format_exc()
                 log.debug("Invalid Git path `%s`, tb: %s", path, tb)
                 return False
+                return True
 
-            return True
-        return _assert_correct_path(context_uid, repo_id)
+        return _assert_correct_path(context_uid, repo_id, True)
 
     @reraise_safe_exceptions
     def bare(self, wire):
@@ -672,7 +678,7 b' class GitRemote(RemoteBase):'
 
     @reraise_safe_exceptions
     def sync_fetch(self, wire, url, refs=None, all_refs=False):
-        repo = self._factory.repo(wire)
+        self._factory.repo(wire)
         if refs and not isinstance(refs, (list, tuple)):
             refs = [refs]
 
@@ -1315,9 +1321,8 b' class GitRemote(RemoteBase):'
         bare = self.bare(wire)
         path = wire['path']
         binary_dir = settings.BINARY_DIR
-        executable = None
         if binary_dir:
-            executable = os.path.join(binary_dir, 'python3')
+            os.path.join(binary_dir, 'python3')
         return install_git_hooks(path, bare, force_create=force)
 
     @reraise_safe_exceptions
@@ -1334,9 +1339,11 b' class GitRemote(RemoteBase):'
     @reraise_safe_exceptions
     def set_head_ref(self, wire, head_name):
         log.debug('Setting refs/head to `%s`', head_name)
-        cmd = ['symbolic-ref', '"HEAD"', '"refs/heads/%s"' % head_name]
-        output, __ = self.run_git_command(wire, cmd)
-        return [head_name] + output.splitlines()
+        repo_init = self._factory.repo_libgit2(wire)
+        with repo_init as repo:
+            repo.set_head(f'refs/heads/{head_name}')
+
+        return [head_name] + [f'set HEAD to refs/heads/{head_name}']
 
     @reraise_safe_exceptions
     def archive_repo(self, wire, archive_dest_path, kind, mtime, archive_at_path,
@@ -1362,14 +1369,14 b' class GitRemote(RemoteBase):'
                 index.read_tree(tree)
                 file_iter = index
 
-                for fn in file_iter:
-                    file_path = fn.path
-                    mode = fn.mode
+                for file_node in file_iter:
+                    file_path = file_node.path
+                    mode = file_node.mode
                     is_link = stat.S_ISLNK(mode)
                     if mode == pygit2.GIT_FILEMODE_COMMIT:
                         log.debug('Skipping path %s as a commit node', file_path)
                         continue
-                    yield ArchiveNode(file_path, mode, is_link, repo[fn.hex].read_raw)
+                    yield ArchiveNode(file_path, mode, is_link, repo[file_node.hex].read_raw)
 
         return archive_repo(file_walker, archive_dest_path, kind, mtime, archive_at_path,
                             archive_dir_name, commit_id)

vcsserver/tests/test_pygrack.py

@@ -115,10 +115,14 b' def test_pull_has_hook_messages(pygrack_'
         '0000',
         '0009done\n',
     ])
+
+    pre_pull = 'pre_pull_output'
+    post_pull = 'post_pull_output'
+
     with mock.patch('vcsserver.hooks.git_pre_pull',
-                    return_value=hooks.HookResponse(0, 'foo')):
+                    return_value=hooks.HookResponse(0, pre_pull)):
         with mock.patch('vcsserver.hooks.git_post_pull',
-                        return_value=hooks.HookResponse(1, 'bar')):
+                        return_value=hooks.HookResponse(1, post_pull)):
             with mock.patch('vcsserver.subprocessio.SubprocessIOChunker',
                             return_value=more_itertools.always_iterable([b'0008NAK\n0009subp\n0000'])):
                 response = pygrack_app.post(
@@ -129,7 +133,11 b' def test_pull_has_hook_messages(pygrack_'
     proto = dulwich.protocol.Protocol(data.read, None)
     packets = list(proto.read_pkt_seq())
 
-    assert packets == [b'NAK\n', b'\x02foo', b'subp\n', b'\x02bar']
+    assert packets == [b'NAK\n',
+                       # pre-pull only outputs if IT FAILS as in != 0 ret code
+                       #b'\x02pre_pull_output',
+                       b'subp\n',
+                       b'\x02post_pull_output']
 
 
 def test_get_want_capabilities(pygrack_instance):