[3.9] bpo-45083: Include the exception class qualname when formatting an exception (GH-28119) (GH-28135)

* bpo-45083: Include the exception class qualname when formatting an exception (GH-28119)

Co-authored-by: Erlend Egeberg Aasland <erlend.aasland@innova.no>
(cherry picked from commit b4b6342848ec0459182a992151099252434cc619)

Co-authored-by: Irit Katriel <1055913+iritkatriel@users.noreply.github.com>
Co-authored-by: Łukasz Langa <lukasz@langa.pl>

1 files changed, 14 insertions, 0 deletions

diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py
index ed9b177..f277c92 100644
--- a/Lib/test/test_sys.py
+++ b/Lib/test/test_sys.py
@@ -1005,6 +1005,20 @@ class UnraisableHookTest(unittest.TestCase):
                     self.assertIn("del is broken", report)
                 self.assertTrue(report.endswith("\n"))
 
+    def test_original_unraisablehook_exception_qualname(self):
+        class A:
+            class B:
+                class X(Exception):
+                    pass
+
+        with test.support.captured_stderr() as stderr, \
+             test.support.swap_attr(sys, 'unraisablehook',
+                                    sys.__unraisablehook__):
+                 expected = self.write_unraisable_exc(
+                     A.B.X(), "msg", "obj");
+        report = stderr.getvalue()
+        testName = 'test_original_unraisablehook_exception_qualname'
+        self.assertIn(f"{testName}.<locals>.A.B.X", report)
 
     def test_original_unraisablehook_wrong_type(self):
         exc = ValueError(42)