gh-117110: Fix subclasses of typing.Any with custom constructors (#117111)

Author: Azureblade3808

Lib/test/test_typing.py

@@ -140,6 +140,26 @@ class MockSomething(Something, Mock): pass
         self.assertIsInstance(ms, Something)
         self.assertIsInstance(ms, Mock)
 
+    def test_subclassing_with_custom_constructor(self):
+        class Sub(Any):
+            def __init__(self, *args, **kwargs): pass
+        # The instantiation must not fail.
+        Sub(0, s="")
+
+    def test_multiple_inheritance_with_custom_constructors(self):
+        class Foo:
+            def __init__(self, x):
+                self.x = x
+
+        class Bar(Any, Foo):
+            def __init__(self, x, y):
+                self.y = y
+                super().__init__(x)
+
+        b = Bar(1, 2)
+        self.assertEqual(b.x, 1)
+        self.assertEqual(b.y, 2)
+
     def test_cannot_instantiate(self):
         with self.assertRaises(TypeError):
             Any()

Lib/typing.py

@@ -539,7 +539,7 @@ class Any(metaclass=_AnyMeta):
     def __new__(cls, *args, **kwargs):
         if cls is Any:
             raise TypeError("Any cannot be instantiated")
-        return super().__new__(cls, *args, **kwargs)
+        return super().__new__(cls)
 
 
 @_SpecialForm

Misc/NEWS.d/next/Library/2024-03-21-07-27-36.gh-issue-117110.9K1InX.rst

@@ -0,0 +1 @@
+Fix a bug that prevents subclasses of :class:`typing.Any` to be instantiated with arguments. Patch by Chris Fu.