Issue #22995: Default implementation of __reduce__ and __reduce_ex__ now

rejects builtin types with not defined __new__.
Added tests for non-pickleable types.

Lib/test/test_coroutines.py

@@ -1,5 +1,7 @@
 import contextlib
+import copy
 import inspect
+import pickle
 import sys
 import types
 import unittest
@@ -1318,6 +1320,34 @@ class CoroutineTest(unittest.TestCase):
             run_async(foo())
         self.assertEqual(CNT, 0)
 
+    def test_copy(self):
+        async def func(): pass
+        coro = func()
+        with self.assertRaises(TypeError):
+            copy.copy(coro)
+
+        aw = coro.__await__()
+        try:
+            with self.assertRaises(TypeError):
+                copy.copy(aw)
+        finally:
+            aw.close()
+
+    def test_pickle(self):
+        async def func(): pass
+        coro = func()
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.assertRaises((TypeError, pickle.PicklingError)):
+                pickle.dumps(coro, proto)
+
+        aw = coro.__await__()
+        try:
+            for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+                with self.assertRaises((TypeError, pickle.PicklingError)):
+                    pickle.dumps(aw, proto)
+        finally:
+            aw.close()
+
 
 class CoroAsyncIOCompatTest(unittest.TestCase):
 

Lib/test/test_dictviews.py

@@ -1,3 +1,5 @@
+import copy
+import pickle
 import unittest
 
 class DictSetTest(unittest.TestCase):
@@ -197,6 +199,22 @@ class DictSetTest(unittest.TestCase):
         d[42] = d.values()
         self.assertRaises(RecursionError, repr, d)
 
+    def test_copy(self):
+        d = {1: 10, "a": "ABC"}
+        self.assertRaises(TypeError, copy.copy, d.keys())
+        self.assertRaises(TypeError, copy.copy, d.values())
+        self.assertRaises(TypeError, copy.copy, d.items())
+
+    def test_pickle(self):
+        d = {1: 10, "a": "ABC"}
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            self.assertRaises((TypeError, pickle.PicklingError),
+                pickle.dumps, d.keys(), proto)
+            self.assertRaises((TypeError, pickle.PicklingError),
+                pickle.dumps, d.values(), proto)
+            self.assertRaises((TypeError, pickle.PicklingError),
+                pickle.dumps, d.items(), proto)
+
 
 if __name__ == "__main__":
     unittest.main()

Lib/test/test_generators.py

@@ -1,4 +1,6 @@
+import copy
 import gc
+import pickle
 import sys
 import unittest
 import warnings
@@ -111,6 +113,21 @@ class GeneratorTest(unittest.TestCase):
         self.assertEqual(gen.__qualname__,
                          "GeneratorTest.test_name.<locals>.<genexpr>")
 
+    def test_copy(self):
+        def f():
+            yield 1
+        g = f()
+        with self.assertRaises(TypeError):
+            copy.copy(g)
+
+    def test_pickle(self):
+        def f():
+            yield 1
+        g = f()
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.assertRaises((TypeError, pickle.PicklingError)):
+                pickle.dumps(g, proto)
+
 
 class ExceptionTest(unittest.TestCase):
     # Tests for the issue #23353: check that the currently handled exception

Lib/test/test_xml_etree.py

@@ -5,6 +5,7 @@
 # For this purpose, the module-level "ET" symbol is temporarily
 # monkey-patched when running the "test_xml_etree_c" test suite.
 
+import copy
 import html
 import io
 import operator
@@ -2082,6 +2083,19 @@ class ElementIterTest(unittest.TestCase):
         self.assertEqual(self._ilist(doc), all_tags)
         self.assertEqual(self._ilist(doc, '*'), all_tags)
 
+    def test_copy(self):
+        a = ET.Element('a')
+        it = a.iter()
+        with self.assertRaises(TypeError):
+            copy.copy(it)
+
+    def test_pickle(self):
+        a = ET.Element('a')
+        it = a.iter()
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.assertRaises((TypeError, pickle.PicklingError)):
+                pickle.dumps(it, proto)
+
 
 class TreeBuilderTest(unittest.TestCase):
     sample1 = ('<!DOCTYPE html PUBLIC'

Lib/test/test_zlib.py

@@ -1,6 +1,7 @@
 import unittest
 from test import support
 import binascii
+import pickle
 import random
 import sys
 from test.support import bigmemtest, _1G, _4G
@@ -600,6 +601,16 @@ class CompressObjectTestCase(BaseCompressTestCase, unittest.TestCase):
         d.flush()
         self.assertRaises(ValueError, d.copy)
 
+    def test_compresspickle(self):
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.assertRaises((TypeError, pickle.PicklingError)):
+                pickle.dumps(zlib.compressobj(zlib.Z_BEST_COMPRESSION), proto)
+
+    def test_decompresspickle(self):
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.assertRaises((TypeError, pickle.PicklingError)):
+                pickle.dumps(zlib.decompressobj(), proto)
+
     # Memory use of the following functions takes into account overallocation
 
     @bigmemtest(size=_1G + 1024 * 1024, memuse=3)

Misc/NEWS

@@ -11,6 +11,9 @@ Release date: TBA
 Core and Builtins
 -----------------
 
+- Issue #22995: Default implementation of __reduce__ and __reduce_ex__ now
+  rejects builtin types with not defined __new__.
+
 - Issue #25555: Fix parser and AST: fill lineno and col_offset of "arg" node
   when compiling AST from Python objects.
 

Objects/typeobject.c

@@ -4100,6 +4100,12 @@ reduce_newobj(PyObject *obj, int proto)
     PyObject *newobj, *newargs, *state, *listitems, *dictitems;
     PyObject *result;
 
+    if (Py_TYPE(obj)->tp_new == NULL) {
+        PyErr_Format(PyExc_TypeError,
+                     "can't pickle %s objects",
+                     Py_TYPE(obj)->tp_name);
+        return NULL;
+    }
     if (_PyObject_GetNewArguments(obj, &args, &kwargs) < 0)
         return NULL;