sync: Don't checkout if no worktree

Interleaved sync should not try checkout out a project if it's a mirror.

Change-Id: I2549faab197a3202d79a10e44b449b68d53e3fe7

subcmds/sync.py

@@ -2269,7 +2269,13 @@ later is required to fix a server side protocol bug.
         checkout_finish = None
         checkout_stderr = ""
 
-        if fetch_success and not opt.network_only:
+        if fetch_success:
+            # We skip checkout if it's network-only or if the project has no
+            # working tree (e.g., a mirror).
+            if opt.network_only or not project.worktree:
+                checkout_success = True
+            else:
+                # This is a normal project that needs a checkout.
                 checkout_start = time.time()
                 stderr_capture = io.StringIO()
                 try:

tests/test_subcmds_sync.py

@@ -309,6 +309,7 @@ class FakeProject:
         self.relpath = relpath
         self.name = name or relpath
         self.objdir = objdir or relpath
+        self.worktree = relpath
 
         self.use_git_worktrees = False
         self.UseAlternates = False
@@ -836,6 +837,25 @@ class InterleavedSyncTest(unittest.TestCase):
         project.Sync_NetworkHalf.assert_called_once()
         project.Sync_LocalHalf.assert_not_called()
 
+    def test_worker_no_worktree(self):
+        """Test interleaved sync does not checkout a project with no worktree."""
+        opt = self._get_opts()
+        project = self.projA
+        project.worktree = None
+        project.Sync_NetworkHalf = mock.Mock(
+            return_value=SyncNetworkHalfResult(error=None, remote_fetched=True)
+        )
+        project.Sync_LocalHalf = mock.Mock()
+        self.mock_context["projects"] = [project]
+
+        result_obj = self.cmd._SyncProjectList(opt, [0])
+        result = result_obj.results[0]
+
+        self.assertTrue(result.fetch_success)
+        self.assertTrue(result.checkout_success)
+        project.Sync_NetworkHalf.assert_called_once()
+        project.Sync_LocalHalf.assert_not_called()
+
     def test_worker_fetch_fails_exception(self):
         """Test _SyncProjectList with an exception during fetch."""
         opt = self._get_opts()