Revert "bpo-35621: Support running subprocesses in asyncio when loop is...

Revert "bpo-35621: Support running subprocesses in asyncio when loop is executed in non-main thread (#13630)" (GH-13793)



https://bugs.python.org/issue35621

Lib/test/test_asyncio/test_subprocess.py

@@ -633,7 +633,6 @@ class SubprocessMixin:
 
         self.assertIsNone(self.loop.run_until_complete(execute()))
 
-
 if sys.platform != 'win32':
     # Unix
     class SubprocessWatcherMixin(SubprocessMixin):
@@ -649,24 +648,7 @@ if sys.platform != 'win32':
             watcher = self.Watcher()
             watcher.attach_loop(self.loop)
             policy.set_child_watcher(watcher)
-
-        def tearDown(self):
-            super().setUp()
-            policy = asyncio.get_event_loop_policy()
-            watcher = policy.get_child_watcher()
-            policy.set_child_watcher(None)
-            watcher.attach_loop(None)
-            watcher.close()
-
-    class SubprocessThreadedWatcherTests(SubprocessWatcherMixin,
-                                         test_utils.TestCase):
-
-        Watcher = unix_events.ThreadedChildWatcher
-
-    class SubprocessMultiLoopWatcherTests(SubprocessWatcherMixin,
-                                          test_utils.TestCase):
-
-        Watcher = unix_events.MultiLoopChildWatcher
+            self.addCleanup(policy.set_child_watcher, None)
 
     class SubprocessSafeWatcherTests(SubprocessWatcherMixin,
                                      test_utils.TestCase):
@@ -688,25 +670,5 @@ else:
             self.set_event_loop(self.loop)
 
 
-class GenericWatcherTests:
-
-    def test_create_subprocess_fails_with_inactive_watcher(self):
-
-        async def execute():
-            watcher = mock.create_authspec(asyncio.AbstractChildWatcher)
-            watcher.is_active.return_value = False
-            asyncio.set_child_watcher(watcher)
-
-            with self.assertRaises(RuntimeError):
-                await subprocess.create_subprocess_exec(
-                    support.FakePath(sys.executable), '-c', 'pass')
-
-            watcher.add_child_handler.assert_not_called()
-
-        self.assertIsNone(self.loop.run_until_complete(execute()))
-
-
-
-
 if __name__ == '__main__':
     unittest.main()

Lib/test/test_asyncio/test_unix_events.py

@@ -1082,8 +1082,6 @@ class AbstractChildWatcherTests(unittest.TestCase):
             NotImplementedError, watcher.attach_loop, f)
         self.assertRaises(
             NotImplementedError, watcher.close)
-        self.assertRaises(
-            NotImplementedError, watcher.is_active)
         self.assertRaises(
             NotImplementedError, watcher.__enter__)
         self.assertRaises(
@@ -1786,6 +1784,15 @@ class ChildWatcherTestsMixin:
                 if isinstance(self.watcher, asyncio.FastChildWatcher):
                     self.assertFalse(self.watcher._zombies)
 
+    @waitpid_mocks
+    def test_add_child_handler_with_no_loop_attached(self, m):
+        callback = mock.Mock()
+        with self.create_watcher() as watcher:
+            with self.assertRaisesRegex(
+                    RuntimeError,
+                    'the child watcher does not have a loop attached'):
+                watcher.add_child_handler(100, callback)
+
 
 class SafeChildWatcherTests (ChildWatcherTestsMixin, test_utils.TestCase):
     def create_watcher(self):
@@ -1802,16 +1809,17 @@ class PolicyTests(unittest.TestCase):
     def create_policy(self):
         return asyncio.DefaultEventLoopPolicy()
 
-    def test_get_default_child_watcher(self):
+    def test_get_child_watcher(self):
         policy = self.create_policy()
         self.assertIsNone(policy._watcher)
 
         watcher = policy.get_child_watcher()
-        self.assertIsInstance(watcher, asyncio.ThreadedChildWatcher)
+        self.assertIsInstance(watcher, asyncio.SafeChildWatcher)
 
         self.assertIs(policy._watcher, watcher)
 
         self.assertIs(watcher, policy.get_child_watcher())
+        self.assertIsNone(watcher._loop)
 
     def test_get_child_watcher_after_set(self):
         policy = self.create_policy()
@@ -1821,6 +1829,18 @@ class PolicyTests(unittest.TestCase):
         self.assertIs(policy._watcher, watcher)
         self.assertIs(watcher, policy.get_child_watcher())
 
+    def test_get_child_watcher_with_mainloop_existing(self):
+        policy = self.create_policy()
+        loop = policy.get_event_loop()
+
+        self.assertIsNone(policy._watcher)
+        watcher = policy.get_child_watcher()
+
+        self.assertIsInstance(watcher, asyncio.SafeChildWatcher)
+        self.assertIs(watcher._loop, loop)
+
+        loop.close()
+
     def test_get_child_watcher_thread(self):
 
         def f():
@@ -1846,11 +1866,7 @@ class PolicyTests(unittest.TestCase):
         policy = self.create_policy()
         loop = policy.get_event_loop()
 
-        # Explicitly setup SafeChildWatcher,
-        # default ThreadedChildWatcher has no _loop property
-        watcher = asyncio.SafeChildWatcher()
-        policy.set_child_watcher(watcher)
-        watcher.attach_loop(loop)
+        watcher = policy.get_child_watcher()
 
         self.assertIs(watcher._loop, loop)
 

Misc/NEWS.d/next/Library/2019-05-28-19-03-46.bpo-35621.Abc1lf.rst

-Support running asyncio subprocesses when execution event loop in a thread
-on UNIX.