gh-101860: Expose __name__ on property (GH-101876)

Useful for introspection and consistent with functions and other
descriptors.

5 files changed, 76 insertions, 14 deletions

diff --git a/Lib/inspect.py b/Lib/inspect.py
index 450093a..da50403 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -834,9 +834,8 @@ def _finddoc(obj):
             cls = self.__class__
     # Should be tested before isdatadescriptor().
     elif isinstance(obj, property):
-        func = obj.fget
-        name = func.__name__
-        cls = _findclass(func)
+        name = obj.__name__
+        cls = _findclass(obj.fget)
         if cls is None or getattr(cls, name) is not obj:
             return None
     elif ismethoddescriptor(obj) or isdatadescriptor(obj):
diff --git a/Lib/pydoc.py b/Lib/pydoc.py
index 9bb64fe..d32fa8d 100755
--- a/Lib/pydoc.py
+++ b/Lib/pydoc.py
@@ -127,9 +127,8 @@ def _finddoc(obj):
             cls = self.__class__
     # Should be tested before isdatadescriptor().
     elif isinstance(obj, property):
-        func = obj.fget
-        name = func.__name__
-        cls = _findclass(func)
+        name = obj.__name__
+        cls = _findclass(obj.fget)
         if cls is None or getattr(cls, name) is not obj:
             return None
     elif inspect.ismethoddescriptor(obj) or inspect.isdatadescriptor(obj):
diff --git a/Lib/test/test_inspect/inspect_fodder.py b/Lib/test/test_inspect/inspect_fodder.py
index 60ba7aa..febd54c 100644
--- a/Lib/test/test_inspect/inspect_fodder.py
+++ b/Lib/test/test_inspect/inspect_fodder.py
@@ -68,9 +68,9 @@ class FesteringGob(MalodorousPervert, ParrotDroppings):
     def abuse(self, a, b, c):
         pass
 
-    @property
-    def contradiction(self):
+    def _getter(self):
         pass
+    contradiction = property(_getter)
 
 async def lobbest(grenade):
     pass
diff --git a/Lib/test/test_property.py b/Lib/test/test_property.py
index ad5ab5a..408e64f 100644
--- a/Lib/test/test_property.py
+++ b/Lib/test/test_property.py
@@ -201,6 +201,59 @@ class PropertyTests(unittest.TestCase):
         self.assertIsNone(prop.fdel)
         self.assertAlmostEqual(gettotalrefcount() - refs_before, 0, delta=10)
 
+    def test_property_name(self):
+        def getter(self):
+            return 42
+
+        def setter(self, value):
+            pass
+
+        class A:
+            @property
+            def foo(self):
+                return 1
+
+            @foo.setter
+            def oof(self, value):
+                pass
+
+            bar = property(getter)
+            baz = property(None, setter)
+
+        self.assertEqual(A.foo.__name__, 'foo')
+        self.assertEqual(A.oof.__name__, 'oof')
+        self.assertEqual(A.bar.__name__, 'bar')
+        self.assertEqual(A.baz.__name__, 'baz')
+
+        A.quux = property(getter)
+        self.assertEqual(A.quux.__name__, 'getter')
+        A.quux.__name__ = 'myquux'
+        self.assertEqual(A.quux.__name__, 'myquux')
+        self.assertEqual(A.bar.__name__, 'bar')  # not affected
+        A.quux.__name__ = None
+        self.assertIsNone(A.quux.__name__)
+
+        with self.assertRaisesRegex(
+            AttributeError, "'property' object has no attribute '__name__'"
+        ):
+            property(None, setter).__name__
+
+        with self.assertRaisesRegex(
+            AttributeError, "'property' object has no attribute '__name__'"
+        ):
+            property(1).__name__
+
+        class Err:
+            def __getattr__(self, attr):
+                raise RuntimeError('fail')
+
+        p = property(Err())
+        with self.assertRaisesRegex(RuntimeError, 'fail'):
+            p.__name__
+
+        p.__name__ = 'not_fail'
+        self.assertEqual(p.__name__, 'not_fail')
+
     def test_property_set_name_incorrect_args(self):
         p = property()
 
diff --git a/Lib/test/test_pydoc/test_pydoc.py b/Lib/test/test_pydoc/test_pydoc.py
index d7a333a..b07d911 100644
--- a/Lib/test/test_pydoc/test_pydoc.py
+++ b/Lib/test/test_pydoc/test_pydoc.py
@@ -1162,6 +1162,17 @@ class PydocImportTest(PydocBaseTest):
         self.assertEqual(loaded_pydoc.__spec__, pydoc.__spec__)
 
 
+class Rect:
+    @property
+    def area(self):
+        '''Area of the rect'''
+        return self.w * self.h
+
+
+class Square(Rect):
+    area = property(lambda self: self.side**2)
+
+
 class TestDescriptions(unittest.TestCase):
 
     def test_module(self):
@@ -1550,13 +1561,13 @@ cm(x) class method of test.test_pydoc.test_pydoc.X
 
     @requires_docstrings
     def test_property(self):
-        class Rect:
-            @property
-            def area(self):
-                '''Area of the rect'''
-                return self.w * self.h
-
         self.assertEqual(self._get_summary_lines(Rect.area), """\
+area
+    Area of the rect
+""")
+        # inherits the docstring from Rect.area
+        self.assertEqual(self._get_summary_lines(Square.area), """\
+area
     Area of the rect
 """)
         self.assertIn("""