From 82592c9815409a1e023152f565a65b0105565ed2 Mon Sep 17 00:00:00 2001 From: Mariusz Felisiak Date: Mon, 28 Jul 2025 23:21:17 +0200 Subject: [PATCH] Fixed #36531 -- Added forkserver support to parallel test runner. --- django/db/backends/sqlite3/creation.py | 10 +++++----- django/test/runner.py | 16 ++++++++++------ tests/backends/sqlite/test_creation.py | 4 ++-- tests/test_runner/test_discover_runner.py | 10 ++++++++++ 4 files changed, 27 insertions(+), 13 deletions(-) diff --git a/django/db/backends/sqlite3/creation.py b/django/db/backends/sqlite3/creation.py index 802e8b8357..8a07e0c417 100644 --- a/django/db/backends/sqlite3/creation.py +++ b/django/db/backends/sqlite3/creation.py @@ -62,7 +62,7 @@ class DatabaseCreation(BaseDatabaseCreation): start_method = multiprocessing.get_start_method() if start_method == "fork": return orig_settings_dict - if start_method == "spawn": + if start_method in {"forkserver", "spawn"}: return { **orig_settings_dict, "NAME": f"{self.connection.alias}_{suffix}.sqlite3", @@ -99,9 +99,9 @@ class DatabaseCreation(BaseDatabaseCreation): self.log("Got an error cloning the test database: %s" % e) sys.exit(2) # Forking automatically makes a copy of an in-memory database. - # Spawn requires migrating to disk which will be re-opened in - # setup_worker_connection. - elif multiprocessing.get_start_method() == "spawn": + # Forkserver and spawn require migrating to disk which will be + # re-opened in setup_worker_connection. + elif multiprocessing.get_start_method() in {"forkserver", "spawn"}: ondisk_db = sqlite3.connect(target_database_name, uri=True) self.connection.connection.backup(ondisk_db) ondisk_db.close() @@ -137,7 +137,7 @@ class DatabaseCreation(BaseDatabaseCreation): # Update settings_dict in place. self.connection.settings_dict.update(settings_dict) self.connection.close() - elif start_method == "spawn": + elif start_method in {"forkserver", "spawn"}: alias = self.connection.alias connection_str = ( f"file:memorydb_{alias}_{_worker_id}?mode=memory&cache=shared" diff --git a/django/test/runner.py b/django/test/runner.py index b83cd37343..cc2fb2ebdf 100644 --- a/django/test/runner.py +++ b/django/test/runner.py @@ -387,8 +387,9 @@ def get_max_test_processes(): The maximum number of test processes when using the --parallel option. """ # The current implementation of the parallel test runner requires - # multiprocessing to start subprocesses with fork() or spawn(). - if multiprocessing.get_start_method() not in {"fork", "spawn"}: + # multiprocessing to start subprocesses with fork(), forkserver(), or + # spawn(). + if multiprocessing.get_start_method() not in {"fork", "spawn", "forkserver"}: return 1 try: return int(os.environ["DJANGO_TEST_PROCESSES"]) @@ -433,9 +434,12 @@ def _init_worker( counter.value += 1 _worker_id = counter.value - start_method = multiprocessing.get_start_method() + is_spawn_or_forkserver = multiprocessing.get_start_method() in { + "forkserver", + "spawn", + } - if start_method == "spawn": + if is_spawn_or_forkserver: if process_setup and callable(process_setup): if process_setup_args is None: process_setup_args = () @@ -446,7 +450,7 @@ def _init_worker( db_aliases = used_aliases if used_aliases is not None else connections for alias in db_aliases: connection = connections[alias] - if start_method == "spawn": + if is_spawn_or_forkserver: # Restore initial settings in spawned processes. connection.settings_dict.update(initial_settings[alias]) if value := serialized_contents.get(alias): @@ -589,7 +593,7 @@ class ParallelTestSuite(unittest.TestSuite): return iter(self.subsuites) def initialize_suite(self): - if multiprocessing.get_start_method() == "spawn": + if multiprocessing.get_start_method() in {"forkserver", "spawn"}: self.initial_settings = { alias: connections[alias].settings_dict for alias in connections } diff --git a/tests/backends/sqlite/test_creation.py b/tests/backends/sqlite/test_creation.py index 8aa24674d2..fe3959c85b 100644 --- a/tests/backends/sqlite/test_creation.py +++ b/tests/backends/sqlite/test_creation.py @@ -36,8 +36,8 @@ class TestDbSignatureTests(SimpleTestCase): clone_settings_dict = creation_class.get_test_db_clone_settings("1") self.assertEqual(clone_settings_dict["NAME"], expected_clone_name) - @mock.patch.object(multiprocessing, "get_start_method", return_value="forkserver") + @mock.patch.object(multiprocessing, "get_start_method", return_value="unsupported") def test_get_test_db_clone_settings_not_supported(self, *mocked_objects): - msg = "Cloning with start method 'forkserver' is not supported." + msg = "Cloning with start method 'unsupported' is not supported." with self.assertRaisesMessage(NotSupportedError, msg): connection.creation.get_test_db_clone_settings(1) diff --git a/tests/test_runner/test_discover_runner.py b/tests/test_runner/test_discover_runner.py index 4f13cceeff..c6ce7f1e1d 100644 --- a/tests/test_runner/test_discover_runner.py +++ b/tests/test_runner/test_discover_runner.py @@ -98,6 +98,16 @@ class DiscoverRunnerParallelArgumentTests(SimpleTestCase): mocked_cpu_count, ): mocked_get_start_method.return_value = "forkserver" + self.assertEqual(get_max_test_processes(), 12) + with mock.patch.dict(os.environ, {"DJANGO_TEST_PROCESSES": "7"}): + self.assertEqual(get_max_test_processes(), 7) + + def test_get_max_test_processes_other( + self, + mocked_get_start_method, + mocked_cpu_count, + ): + mocked_get_start_method.return_value = "other" self.assertEqual(get_max_test_processes(), 1) with mock.patch.dict(os.environ, {"DJANGO_TEST_PROCESSES": "7"}): self.assertEqual(get_max_test_processes(), 1)