gh-136285: Improve pickle protocol testing in test_interpreters (#136286)

Lib/concurrent/interpreters/__init__.py

@@ -146,12 +146,8 @@ class Interpreter:
         self._decref()
 
     # for pickling:
-    def __getnewargs__(self):
-        return (self._id,)
-
-    # for pickling:
-    def __getstate__(self):
-        return None
+    def __reduce__(self):
+        return (type(self), (self._id,))
 
     def _decref(self):
         if not self._ownsref:

Lib/concurrent/interpreters/_queues.py

@@ -129,12 +129,8 @@ class Queue:
         return hash(self._id)
 
     # for pickling:
-    def __getnewargs__(self):
-        return (self._id,)
-
-    # for pickling:
-    def __getstate__(self):
-        return None
+    def __reduce__(self):
+        return (type(self), (self._id,))
 
     def _set_unbound(self, op, items=None):
         assert not hasattr(self, '_unbound')

Lib/test/support/channels.py

@@ -105,12 +105,8 @@ class _ChannelEnd:
         return other._id == self._id
 
     # for pickling:
-    def __getnewargs__(self):
-        return (int(self._id),)
-
-    # for pickling:
-    def __getstate__(self):
-        return None
+    def __reduce__(self):
+        return (type(self), (int(self._id),))
 
     @property
     def id(self):

Lib/test/test_interpreters/test_api.py

@@ -412,9 +412,11 @@ class InterpreterObjectTests(TestBase):
 
     def test_pickle(self):
         interp = interpreters.create()
-        data = pickle.dumps(interp)
-        unpickled = pickle.loads(data)
-        self.assertEqual(unpickled, interp)
+        for protocol in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.subTest(protocol=protocol):
+                data = pickle.dumps(interp, protocol)
+                unpickled = pickle.loads(data)
+                self.assertEqual(unpickled, interp)
 
 
 class TestInterpreterIsRunning(TestBase):

Lib/test/test_interpreters/test_channels.py

@@ -121,9 +121,11 @@ class TestRecvChannelAttrs(TestBase):
 
     def test_pickle(self):
         ch, _ = channels.create()
-        data = pickle.dumps(ch)
-        unpickled = pickle.loads(data)
-        self.assertEqual(unpickled, ch)
+        for protocol in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.subTest(protocol=protocol):
+                data = pickle.dumps(ch, protocol)
+                unpickled = pickle.loads(data)
+                self.assertEqual(unpickled, ch)
 
 
 class TestSendChannelAttrs(TestBase):
@@ -152,9 +154,11 @@ class TestSendChannelAttrs(TestBase):
 
     def test_pickle(self):
         _, ch = channels.create()
-        data = pickle.dumps(ch)
-        unpickled = pickle.loads(data)
-        self.assertEqual(unpickled, ch)
+        for protocol in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.subTest(protocol=protocol):
+                data = pickle.dumps(ch, protocol)
+                unpickled = pickle.loads(data)
+                self.assertEqual(unpickled, ch)
 
 
 class TestSendRecv(TestBase):

Lib/test/test_interpreters/test_queues.py

@@ -188,9 +188,11 @@ class QueueTests(TestBase):
 
     def test_pickle(self):
         queue = queues.create()
-        data = pickle.dumps(queue)
-        unpickled = pickle.loads(data)
-        self.assertEqual(unpickled, queue)
+        for protocol in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.subTest(protocol=protocol):
+                data = pickle.dumps(queue, protocol)
+                unpickled = pickle.loads(data)
+                self.assertEqual(unpickled, queue)
 
 
 class TestQueueOps(TestBase):

Misc/NEWS.d/next/Library/2025-07-05-09-45-04.gh-issue-136286.N67Amr.rst

@@ -0,0 +1,2 @@
+Fix pickling failures for protocols 0 and 1 for many objects realted to
+subinterpreters.