gh-112640: Add kwdefaults parameter to types.FunctionType.__new__ (#112641)

Author: sobolevn

Include/internal/pycore_global_objects_fini_generated.h

@@ -504,6 +504,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(kw)
         STRUCT_FOR_ID(kw1)
         STRUCT_FOR_ID(kw2)
+        STRUCT_FOR_ID(kwdefaults)
         STRUCT_FOR_ID(lambda)
         STRUCT_FOR_ID(last)
         STRUCT_FOR_ID(last_exc)

Include/internal/pycore_global_strings.h

@@ -2263,5 +2263,38 @@ def coro():
             'close', 'throw'}))
 
 
+class FunctionTests(unittest.TestCase):
+    def test_function_type_defaults(self):
+        def ex(a, /, b, *, c):
+            return a + b + c
+
+        func = types.FunctionType(
+            ex.__code__, {}, "func", (1, 2), None, {'c': 3},
+        )
+
+        self.assertEqual(func(), 6)
+        self.assertEqual(func.__defaults__, (1, 2))
+        self.assertEqual(func.__kwdefaults__, {'c': 3})
+
+        func = types.FunctionType(
+            ex.__code__, {}, "func", None, None, None,
+        )
+        self.assertEqual(func.__defaults__, None)
+        self.assertEqual(func.__kwdefaults__, None)
+
+    def test_function_type_wrong_defaults(self):
+        def ex(a, /, b, *, c):
+            return a + b + c
+
+        with self.assertRaisesRegex(TypeError, 'arg 4'):
+            types.FunctionType(
+                ex.__code__, {}, "func", 1, None, {'c': 3},
+            )
+        with self.assertRaisesRegex(TypeError, 'arg 6'):
+            types.FunctionType(
+                ex.__code__, {}, "func", None, None, 3,
+            )
+
+
 if __name__ == '__main__':
     unittest.main()

Include/internal/pycore_runtime_init_generated.h

@@ -0,0 +1,2 @@
+Add ``kwdefaults`` parameter to :data:`types.FunctionType` to set
+default keyword argument values.

Include/internal/pycore_unicodeobject_generated.h

@@ -809,14 +809,17 @@ function.__new__ as func_new
         a tuple that specifies the default argument values
     closure: object = None
         a tuple that supplies the bindings for free variables
+    kwdefaults: object = None
+        a dictionary that specifies the default keyword argument values
 
 Create a function object.
 [clinic start generated code]*/
 
 static PyObject *
 func_new_impl(PyTypeObject *type, PyCodeObject *code, PyObject *globals,
-              PyObject *name, PyObject *defaults, PyObject *closure)
-/*[clinic end generated code: output=99c6d9da3a24e3be input=93611752fc2daf11]*/
+              PyObject *name, PyObject *defaults, PyObject *closure,
+              PyObject *kwdefaults)
+/*[clinic end generated code: output=de72f4c22ac57144 input=20c9c9f04ad2d3f2]*/
 {
     PyFunctionObject *newfunc;
     Py_ssize_t nclosure;
@@ -843,6 +846,11 @@ func_new_impl(PyTypeObject *type, PyCodeObject *code, PyObject *globals,
             return NULL;
         }
     }
+    if (kwdefaults != Py_None && !PyDict_Check(kwdefaults)) {
+        PyErr_SetString(PyExc_TypeError,
+                        "arg 6 (kwdefaults) must be None or dict");
+        return NULL;
+    }
 
     /* check that the closure is well-formed */
     nclosure = closure == Py_None ? 0 : PyTuple_GET_SIZE(closure);
@@ -879,6 +887,9 @@ func_new_impl(PyTypeObject *type, PyCodeObject *code, PyObject *globals,
     if (closure != Py_None) {
         newfunc->func_closure = Py_NewRef(closure);
     }
+    if (kwdefaults != Py_None) {
+        newfunc->func_kwdefaults = Py_NewRef(kwdefaults);
+    }
 
     return (PyObject *)newfunc;
 }