bpo-43234: Prohibit non-ThreadPoolExecutor in loop.set_default_executor

python · serhiy-storchaka · Jul 1, 2021 · Feb 15, 2021 · Jun 29, 2021 · Jun 29, 2021
commit ab33a36a23463d126739ff177520020b29416dc5
@@ -1127,16 +1127,12 @@ Executing code in thread or process pools
 .. method:: loop.set_default_executor(executor)
 
    Set *executor* as the default executor used by :meth:`run_in_executor`.
-   *executor* should be an instance of
+   *executor* must be an instance of
    :class:`~concurrent.futures.ThreadPoolExecutor`.
 
-   .. deprecated:: 3.8
-      Using an executor that is not an instance of
-      :class:`~concurrent.futures.ThreadPoolExecutor` is deprecated and
-      will trigger an error in Python 3.9.
-
-   *executor* must be an instance of
-   :class:`concurrent.futures.ThreadPoolExecutor`.
+   .. deprecated-removed:: 3.8 3.10
+      Accepting an ``executor`` that is not an instance of
+      :class:`~concurrent.futures.ThreadPoolExecutor`.
 
 
 Error Handling API

diff --git a/Doc/whatsnew/3.10.rst b/Doc/whatsnew/3.10.rst
@@ -725,6 +725,10 @@ Removed
   (Contributed by Yurii Karabas, Andrew Svetlov, Yury Selivanov and Kyle Stanley
   in :issue:`42392`.)
 
+* Prohibited passing non-:class:`concurrent.futures.ThreadPoolExecutor`
+  executors to :meth:`loop.set_default_executor` following a deprecation in
+  Python 3.8.
+  (Contributed by Illia Volochii in :issue:`43234`.)
 
 Porting to Python 3.10
 ======================

@@ -814,11 +814,9 @@ def run_in_executor(self, executor, func, *args):
 
     def set_default_executor(self, executor):
         if not isinstance(executor, concurrent.futures.ThreadPoolExecutor):
-            warnings.warn(
+            raise RuntimeError(
                 'Using the default executor that is not an instance of '
-                'ThreadPoolExecutor is deprecated and will be prohibited '
-                'in Python 3.9',
-                DeprecationWarning, 2)
+                'ThreadPoolExecutor is prohibited')
         self._default_executor = executor
 
     def _getaddrinfo_debug(self, host, port, family, type, proto, flags):

@@ -227,7 +227,7 @@ def submit(self, fn, *args, **kwargs):
     def test_set_default_executor_deprecation_warnings(self):
         executor = mock.Mock()
 
-        with self.assertWarns(DeprecationWarning):
+        with self.assertRaises(RuntimeError):
             self.loop.set_default_executor(executor)
 
         # Avoid cleaning up the executor mock

diff --git a/Misc/NEWS.d/next/Library/2021-02-15-22-14-31.bpo-43234.F-vKAT.rst b/Misc/NEWS.d/next/Library/2021-02-15-22-14-31.bpo-43234.F-vKAT.rst
@@ -0,0 +1,3 @@
+Prohibit passing non-:class:`concurrent.futures.ThreadPoolExecutor`
+executors to :meth:`loop.set_default_executor` following a deprecation in
+Python 3.8. Patch by Illia Volochii.