python · sobolevn · Dec 23, 2021 · Dec 23, 2021 · Dec 23, 2021 · Dec 23, 2021
diff --git a/Lib/test/ann_module7.py b/Lib/test/ann_module7.py
@@ -0,0 +1,5 @@
+# Test that generic `property` works with future import.
+
+from __future__ import annotations
+
+p: property[int, str] = property()
diff --git a/Lib/test/test_genericalias.py b/Lib/test/test_genericalias.py
@@ -83,7 +83,9 @@ class BaseTest(unittest.TestCase):
                      WeakSet, ReferenceType, ref,
                      ShareableList, MPSimpleQueue,
                      Future, _WorkItem,
-                     Morsel]
+                     Morsel,
+                     property,
+                     ]
     if ctypes is not None:
         generic_types.extend((ctypes.Array, ctypes.LibraryLoader))
 

diff --git a/Lib/test/test_property.py b/Lib/test/test_property.py
@@ -4,6 +4,8 @@
 import sys
 import unittest
 from test import support
+from types import GenericAlias
+from typing import TypeVar, get_type_hints
 
 class PropertyBase(Exception):
     pass
@@ -215,6 +217,82 @@ def test_property_set_name_incorrect_args(self):
                 p.__set_name__(*([0] * i))
 
 
+class Getter:
+    @property
+    def a(self) -> int:
+        pass
+
+class GetterSetter:
+    @property
+    def a(self) -> int:
+        pass
+    @a.setter
+    def a(self, arg: str) -> None:
+        pass
+
+class GetterSetterDeleter:
+    @property
+    def a(self) -> int:
+        pass
+    @a.setter
+    def a(self, arg: str) -> None:
+        pass
+    @a.deleter
+    def a(self) -> None:
+        pass
+
+
+class GenericPropertyTests(unittest.TestCase):
+    def test_property___class_getitem__(self):
+        p = property[int, str]
+        self.assertIsInstance(p, GenericAlias)
+        self.assertIs(p.__origin__, property)
+        self.assertEqual(p.__args__, (int, str))
+        self.assertEqual(p.__parameters__, ())
+
+        G = TypeVar('G')
+        S = TypeVar('S')
+        p1 = property[G, S]
+        self.assertEqual(p1.__args__, (G, S))
+        self.assertEqual(p1.__parameters__, (G, S))
+
+        # The number of type arguments is not limited:
+        p2 = property[int, str, bool]
+        self.assertEqual(p2.__args__, (int, str, bool))
+        p3 = property[str]
+        self.assertEqual(p3.__args__, (str,))
+
+    def test_property_and_get_type_hints(self):
+        # Properties should not be present in `get_type_hints`
+        # or `__annotations__` of a class.
+        for klass in (Getter, GetterSetter, GetterSetterDeleter):
+            with self.subTest(klass=klass):
+                self.assertEqual(get_type_hints(klass), {})
+                self.assertEqual(klass.__annotations__, {})
+                # Getting hints of `property` itself is not allowed
+                with self.assertRaises(TypeError):
+                    get_type_hints(klass.a)
+
+    def test_property_inner_annotations(self):
+        from inspect import getattr_static
+
+        p1 = getattr_static(Getter, 'a')
+        self.assertEqual(get_type_hints(p1.fget), {'return': int})
+
+        p2 = getattr_static(GetterSetter, 'a')
+        self.assertEqual(get_type_hints(p2.fget), {'return': int})
+        self.assertEqual(get_type_hints(p2.fset), {'arg': str, 'return': type(None)})
+
+        p3 = getattr_static(GetterSetterDeleter, 'a')
+        self.assertEqual(get_type_hints(p3.fget), {'return': int})
+        self.assertEqual(get_type_hints(p3.fset), {'arg': str, 'return': type(None)})
+        self.assertEqual(get_type_hints(p3.fdel), {'return': type(None)})
+
+    def test_property_and_future_import(self):
+        from test import ann_module7
+        self.assertEqual(get_type_hints(ann_module7), {'p': property[int, str]})
+
+
 # Issue 5890: subclasses of property do not preserve method __doc__ strings
 class PropertySub(property):
     """This is a subclass of property"""

diff --git a/Misc/NEWS.d/next/Library/2021-12-23-12-53-34.bpo-46162.bE3xrz.rst b/Misc/NEWS.d/next/Library/2021-12-23-12-53-34.bpo-46162.bE3xrz.rst
@@ -0,0 +1 @@
+Make :class:`property` generic.
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
@@ -1566,6 +1566,7 @@ static PyMethodDef property_methods[] = {
     {"setter", property_setter, METH_O, setter_doc},
     {"deleter", property_deleter, METH_O, deleter_doc},
     {"__set_name__", property_set_name, METH_VARARGS, set_name_doc},
+    {"__class_getitem__", Py_GenericAlias, METH_O|METH_CLASS, PyDoc_STR("See PEP 585")},
     {0}
 };
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Make :class:`property` generic.
Copy link Member merwok Dec 31, 2021 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others. Learn more. generic can be a bit vague (or generic 😉), could you rephrase this news snippet and the PR title to clarify this is about typing generic alias?