Issue #22423: Unhandled exception in thread no longer causes unhandled

AttributeError when sys.stderr is None.

1 files changed, 83 insertions, 2 deletions

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 7170f60..98f01ee 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -4,7 +4,7 @@ Tests for the threading module.
 
 import test.support
 from test.support import verbose, strip_python_stderr, import_module, cpython_only
-from test.script_helper import assert_python_ok
+from test.script_helper import assert_python_ok, assert_python_failure
 
 import random
 import re
@@ -15,7 +15,6 @@ import time
 import unittest
 import weakref
 import os
-from test.script_helper import assert_python_ok, assert_python_failure
 import subprocess
 
 from test import lock_tests
@@ -962,6 +961,88 @@ class ThreadingExceptionTests(BaseTestCase):
         self.assertEqual(p.returncode, 0, "Unexpected error: " + stderr.decode())
         self.assertEqual(data, expected_output)
 
+    def test_print_exception(self):
+        script = r"""if True:
+            import threading
+            import time
+
+            running = False
+            def run():
+                global running
+                running = True
+                while running:
+                    time.sleep(0.01)
+                1/0
+            t = threading.Thread(target=run)
+            t.start()
+            while not running:
+                time.sleep(0.01)
+            running = False
+            t.join()
+            """
+        rc, out, err = assert_python_ok("-c", script)
+        self.assertEqual(out, b'')
+        err = err.decode()
+        self.assertIn("Exception in thread", err)
+        self.assertIn("Traceback (most recent call last):", err)
+        self.assertIn("ZeroDivisionError", err)
+        self.assertNotIn("Unhandled exception", err)
+
+    def test_print_exception_stderr_is_none_1(self):
+        script = r"""if True:
+            import sys
+            import threading
+            import time
+
+            running = False
+            def run():
+                global running
+                running = True
+                while running:
+                    time.sleep(0.01)
+                1/0
+            t = threading.Thread(target=run)
+            t.start()
+            while not running:
+                time.sleep(0.01)
+            sys.stderr = None
+            running = False
+            t.join()
+            """
+        rc, out, err = assert_python_ok("-c", script)
+        self.assertEqual(out, b'')
+        err = err.decode()
+        self.assertIn("Exception in thread", err)
+        self.assertIn("Traceback (most recent call last):", err)
+        self.assertIn("ZeroDivisionError", err)
+        self.assertNotIn("Unhandled exception", err)
+
+    def test_print_exception_stderr_is_none_2(self):
+        script = r"""if True:
+            import sys
+            import threading
+            import time
+
+            running = False
+            def run():
+                global running
+                running = True
+                while running:
+                    time.sleep(0.01)
+                1/0
+            sys.stderr = None
+            t = threading.Thread(target=run)
+            t.start()
+            while not running:
+                time.sleep(0.01)
+            running = False
+            t.join()
+            """
+        rc, out, err = assert_python_ok("-c", script)
+        self.assertEqual(out, b'')
+        self.assertNotIn("Unhandled exception", err.decode())
+
+
 class TimerTests(BaseTestCase):
 
     def setUp(self):