2 files changed, 60 insertions, 1 deletions
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index 344425b..355a33e 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -36,6 +36,7 @@ import _testcapi
 from collections import deque, UserList
 from itertools import cycle, count
 from test import support
+from test.script_helper import assert_python_ok
 
 import codecs
 import io  # C implementation of io
@@ -2589,8 +2590,46 @@ class TextIOWrapperTest(unittest.TestCase):
                                encoding='quopri_codec')
         self.assertRaises(TypeError, t.read)
 
+    def _check_create_at_shutdown(self, **kwargs):
+        # Issue #20037: creating a TextIOWrapper at shutdown
+        # shouldn't crash the interpreter.
+        iomod = self.io.__name__
+        code = """if 1:
+            import codecs
+            import {iomod} as io
+
+            # Avoid looking up codecs at shutdown
+            codecs.lookup('utf-8')
+
+            class C:
+                def __init__(self):
+                    self.buf = io.BytesIO()
+                def __del__(self):
+                    io.TextIOWrapper(self.buf, **{kwargs})
+                    print("ok")
+            c = C()
+            """.format(iomod=iomod, kwargs=kwargs)
+        return assert_python_ok("-c", code)
+
+    def test_create_at_shutdown_without_encoding(self):
+        rc, out, err = self._check_create_at_shutdown()
+        if err:
+            # Can error out with a RuntimeError if the module state
+            # isn't found.
+            self.assertIn("RuntimeError: could not find io module state",
+                          err.decode())
+        else:
+            self.assertEqual("ok", out.decode().strip())
+
+    def test_create_at_shutdown_with_encoding(self):
+        rc, out, err = self._check_create_at_shutdown(encoding='utf-8',
+                                                      errors='strict')
+        self.assertFalse(err)
+        self.assertEqual("ok", out.decode().strip())
+
 
 class CTextIOWrapperTest(TextIOWrapperTest):
+    io = io
 
     def test_initialization(self):
         r = self.BytesIO(b"\xc3\xa9\n\n")
@@ -2634,7 +2673,7 @@ class CTextIOWrapperTest(TextIOWrapperTest):
 
 
 class PyTextIOWrapperTest(TextIOWrapperTest):
-    pass
+    io = pyio
 
 
 class IncrementalNewlineDecoderTest(unittest.TestCase):
diff --git a/Lib/test/test_logging.py b/Lib/test/test_logging.py
index ce3f84c..3765f36 100644
--- a/Lib/test/test_logging.py
+++ b/Lib/test/test_logging.py
@@ -41,6 +41,7 @@ import socket
 import struct
 import sys
 import tempfile
+from test.script_helper import assert_python_ok
 from test.support import (captured_stdout, run_with_locale, run_unittest,
                           patch, requires_zlib, TestHandler, Matcher)
 import textwrap
@@ -3397,6 +3398,25 @@ class ModuleLevelMiscTest(BaseTest):
         logging.setLoggerClass(logging.Logger)
         self.assertEqual(logging.getLoggerClass(), logging.Logger)
 
+    def test_logging_at_shutdown(self):
+        # Issue #20037
+        code = """if 1:
+            import logging
+
+            class A:
+                def __del__(self):
+                    try:
+                        raise ValueError("some error")
+                    except Exception:
+                        logging.exception("exception in __del__")
+
+            a = A()"""
+        rc, out, err = assert_python_ok("-c", code)
+        err = err.decode()
+        self.assertIn("exception in __del__", err)
+        self.assertIn("ValueError: some error", err)
+
+
 class LogRecordTest(BaseTest):
     def test_str_rep(self):
         r = logging.makeLogRecord({})