sync: Re-raise KeyboardInterrupt in main process

When running sync -j1, worker functions run directly in the main
process. Swallowing KeyboardInterrupt causes the loop to continue to the
next project instead of aborting.

Re-raise KeyboardInterrupt if running in the MainProcess, while
maintaining the suppression of stack traces in worker processes.

Bug: 468170157
Change-Id: I156d66bc209a265f7fa25eea0eb88737d1b51a34
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/581342
Commit-Queue: Gavin Mak <gavinmak@google.com>
Reviewed-by: Mike Frysinger <vapier@google.com>
Tested-by: Gavin Mak <gavinmak@google.com>

3 files changed, 63 insertions, 0 deletions

diff --git a/command.py b/command.py
index e74a94fa3..ee1f68c14 100644
--- a/command.py
+++ b/command.py
@@ -101,6 +101,11 @@ class Command:
     def WantPager(self, _opt):
         return False
 
+    @staticmethod
+    def is_multiprocessing_active() -> bool:
+        """Whether the current process is a worker in a pool."""
+        return multiprocessing.current_process().name != "MainProcess"
+
     def ReadEnvironmentOptions(self, opts):
         """Set options from environment variables."""
 
diff --git a/subcmds/sync.py b/subcmds/sync.py
index b1c30867e..2517694e7 100644
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@@ -841,6 +841,8 @@ later is required to fix a server side protocol bug.
                 )
         except KeyboardInterrupt:
             logger.error("Keyboard interrupt while processing %s", project.name)
+            if not cls.is_multiprocessing_active():
+                raise
         except GitError as e:
             logger.error("error.GitError: Cannot fetch %s", e)
             errors.append(e)
@@ -1104,6 +1106,8 @@ later is required to fix a server side protocol bug.
             errors.extend(syncbuf.errors)
         except KeyboardInterrupt:
             logger.error("Keyboard interrupt while processing %s", project.name)
+            if not cls.is_multiprocessing_active():
+                raise
         except GitError as e:
             logger.error(
                 "error.GitError: Cannot checkout %s: %s", project.name, e
@@ -2410,6 +2414,8 @@ later is required to fix a server side protocol bug.
                 logger.error(
                     "Keyboard interrupt while processing %s", project.name
                 )
+                if not cls.is_multiprocessing_active():
+                    raise
             except GitError as e:
                 fetch_errors.append(e)
                 logger.error("error.GitError: Cannot fetch %s", e)
@@ -2460,6 +2466,8 @@ later is required to fix a server side protocol bug.
                     logger.error(
                         "Keyboard interrupt while processing %s", project.name
                     )
+                    if not cls.is_multiprocessing_active():
+                        raise
                 except GitError as e:
                     checkout_errors.append(e)
                     logger.error(
diff --git a/tests/test_subcmds_sync.py b/tests/test_subcmds_sync.py
index 0a46bbdf3..669027c98 100644
--- a/tests/test_subcmds_sync.py
+++ b/tests/test_subcmds_sync.py
@@ -477,6 +477,56 @@ class GetPreciousObjectsState(unittest.TestCase):
         )
 
 
+class KeyboardInterruptTest(unittest.TestCase):
+    """Tests for KeyboardInterrupt handling in Sync operations."""
+
+    def setUp(self):
+        self.project = mock.MagicMock(name="project")
+        self.project.name = "project"
+        self.project.relpath = "proj"
+        self.project.manifest.IsArchive = False
+        self.opt = mock.Mock()
+        self.opt.quiet = True
+        self.opt.verbose = False
+        self.opt.tags = False
+
+        self.sync_dict = {}
+
+        self.get_parallel_context_mock = {
+            "projects": [self.project],
+            "sync_dict": self.sync_dict,
+            "ssh_proxy": None,
+        }
+
+    @mock.patch("subcmds.sync.Sync.is_multiprocessing_active")
+    def test_fetch_one_keyboard_interrupt_main_process(self, mock_is_active):
+        """Test that _FetchOne re-raises KeyboardInterrupt if not worker."""
+        mock_is_active.return_value = False
+        self.project.Sync_NetworkHalf.side_effect = KeyboardInterrupt()
+
+        with mock.patch.object(
+            sync.Sync,
+            "get_parallel_context",
+            return_value=self.get_parallel_context_mock,
+        ):
+            with self.assertRaises(KeyboardInterrupt):
+                sync.Sync._FetchOne(self.opt, 0)
+
+    @mock.patch("subcmds.sync.Sync.is_multiprocessing_active")
+    def test_fetch_one_keyboard_interrupt_worker_process(self, mock_is_active):
+        """Test that _FetchOne suppresses KeyboardInterrupt in workers."""
+        mock_is_active.return_value = True
+        self.project.Sync_NetworkHalf.side_effect = KeyboardInterrupt()
+
+        with mock.patch.object(
+            sync.Sync,
+            "get_parallel_context",
+            return_value=self.get_parallel_context_mock,
+        ):
+            result = sync.Sync._FetchOne(self.opt, 0)
+            self.assertFalse(result.success)
+
+
 class CheckForBloatedProjects(unittest.TestCase):
     """Tests for Sync._CheckForBloatedProjects."""