gh-66060: Use actual class name in _io type's __repr__ (#30824)

Use the object's actual class name in the following _io type's __repr__:
- FileIO
- TextIOWrapper
- _WindowsConsoleIO

Lib/test/test_fileio.py

@@ -174,6 +174,16 @@ class AutoFileTests:
         self.assertEqual(repr(self.f),
                          "<%s.FileIO [closed]>" % (self.modulename,))
 
+    def test_subclass_repr(self):
+        class TestSubclass(self.FileIO):
+            pass
+
+        f = TestSubclass(TESTFN)
+        with f:
+            self.assertIn(TestSubclass.__name__, repr(f))
+
+        self.assertIn(TestSubclass.__name__, repr(f))
+
     def testReprNoCloseFD(self):
         fd = os.open(TESTFN, os.O_RDONLY)
         try:

Lib/test/test_io.py

@@ -2806,6 +2806,13 @@ class TextIOWrapperTest(unittest.TestCase):
             with self.assertRaises(RuntimeError):
                 repr(t)  # Should not crash
 
+    def test_subclass_repr(self):
+        class TestSubclass(self.TextIOWrapper):
+            pass
+
+        f = TestSubclass(self.StringIO())
+        self.assertIn(TestSubclass.__name__, repr(f))
+
     def test_line_buffering(self):
         r = self.BytesIO()
         b = self.BufferedWriter(r, 1000)

Lib/test/test_winconsoleio.py

@@ -98,6 +98,16 @@ class WindowsConsoleIOTests(unittest.TestCase):
             self.assertIsInstance(f, ConIO)
             f.close()
 
+    def test_subclass_repr(self):
+        class TestSubclass(ConIO):
+            pass
+
+        f = TestSubclass("CON")
+        with f:
+            self.assertIn(TestSubclass.__name__, repr(f))
+
+        self.assertIn(TestSubclass.__name__, repr(f))
+
     @unittest.skipIf(sys.getwindowsversion()[:2] <= (6, 1),
         "test does not work on Windows 7 and earlier")
     def test_conin_conout_names(self):