python · tom-pytel · Jan 29, 2025 · Jan 29, 2025 · Jan 29, 2025 · Jan 29, 2025
diff --git a/Include/internal/pycore_compile.h b/Include/internal/pycore_compile.h
@@ -151,6 +151,7 @@ int _PyCompile_ScopeType(struct _PyCompiler *c);
 int _PyCompile_OptimizationLevel(struct _PyCompiler *c);
 int _PyCompile_LookupArg(struct _PyCompiler *c, PyCodeObject *co, PyObject *name);
 PyObject *_PyCompile_Qualname(struct _PyCompiler *c);
+PyObject *_PyCompile_PeekQualname(struct _PyCompiler *c, PyObject *name);
 _PyCompile_CodeUnitMetadata *_PyCompile_Metadata(struct _PyCompiler *c);
 PyObject *_PyCompile_StaticAttributesAsTuple(struct _PyCompiler *c);


diff --git a/Include/internal/pycore_function.h b/Include/internal/pycore_function.h
@@ -33,7 +33,7 @@ void _PyFunction_ClearCodeByVersion(uint32_t version);
 PyFunctionObject *_PyFunction_LookupByVersion(uint32_t version, PyObject **p_code);

 extern PyObject *_Py_set_function_type_params(
-    PyThreadState* unused, PyObject *func, PyObject *type_params);
+    PyThreadState *ts, PyObject *func, PyObject *type_params);

 #ifdef __cplusplus
 }

diff --git a/Include/internal/pycore_intrinsics.h b/Include/internal/pycore_intrinsics.h
@@ -29,8 +29,9 @@
 #define INTRINSIC_TYPEVAR_WITH_CONSTRAINTS       3
 #define INTRINSIC_SET_FUNCTION_TYPE_PARAMS       4
 #define INTRINSIC_SET_TYPEPARAM_DEFAULT          5
+#define INTRINSIC_SET_TYPEPARAM_OWNER            6

-#define MAX_INTRINSIC_2                          5
+#define MAX_INTRINSIC_2                          6

 typedef PyObject *(*intrinsic_func1)(PyThreadState* tstate, PyObject *value);
 typedef PyObject *(*intrinsic_func2)(PyThreadState* tstate, PyObject *value1, PyObject *value2);

diff --git a/Include/internal/pycore_typevarobject.h b/Include/internal/pycore_typevarobject.h
@@ -14,6 +14,7 @@ extern PyObject *_Py_make_typevartuple(PyThreadState *, PyObject *);
 extern PyObject *_Py_make_typealias(PyThreadState *, PyObject *);
 extern PyObject *_Py_subscript_generic(PyThreadState *, PyObject *);
 extern PyObject *_Py_set_typeparam_default(PyThreadState *, PyObject *, PyObject *);
+extern PyObject *_Py_set_typeparam_owner(PyThreadState *, PyObject *, PyObject *);
 extern int _Py_initialize_generic(PyInterpreterState *);
 extern void _Py_clear_generic_types(PyInterpreterState *);
 extern int _Py_typing_type_repr(PyUnicodeWriter *, PyObject *);

@@ -1183,11 +1183,15 @@ def func1[X](x: X) -> X: ...
 def func2[X, Y](x: X | Y) -> X | Y: ...
 def func3[X, *Y, **Z](x: X, y: tuple[*Y], z: Z) -> X: ...
 def func4[X: int, Y: (bytes, str)](x: X, y: Y) -> X | Y: ...
+def func3b[X, *Y, **Z]() -> X: return Class3[X, Y, Z]()
+def func5[Baz](): return Class1[Baz]()

 class Class1[X]: ...
 class Class2[X, Y]: ...
 class Class3[X, *Y, **Z]: ...
 class Class4[X: int, Y: (bytes, str)]: ...
+class Class5:
+    def meth[Baz](): return Class1[Baz]()


 class TypeParamsPickleTest(unittest.TestCase):
@@ -1240,6 +1244,39 @@ def test_pickling_classes(self):
                    # but class check is good enough:
                    self.assertIsInstance(pickle.loads(pickled), real_class)

+    def test_pickling_anonymous_typeparams(self):
+        # see gh-129250
+        thing = func5()
+        pickled = pickle.dumps(thing)
+        unpickled = pickle.loads(pickled)
+        self.assertIs(unpickled.__orig_class__, thing.__orig_class__)
+        self.assertIs(unpickled.__orig_class__.__args__[0],
+                      func5.__type_params__[0])
+
+        thing = func3b()
+        pickled = pickle.dumps(thing)
+        unpickled = pickle.loads(pickled)
+        self.assertIs(unpickled.__orig_class__, thing.__orig_class__)
+        self.assertIs(unpickled.__orig_class__.__args__[0],
+                      func3b.__type_params__[0])
+        self.assertIs(unpickled.__orig_class__.__args__[1],
+                      func3b.__type_params__[1])
+        self.assertIs(unpickled.__orig_class__.__args__[2],
+                      func3b.__type_params__[2])
+
+        for i in range(3):
+            thing = Class3.__type_params__[i]
+            pickled = pickle.dumps(thing)
+            unpickled = pickle.loads(pickled)
+            self.assertIs(unpickled, thing)
+
+        thing = Class5.meth()
+        pickled = pickle.dumps(thing)
+        unpickled = pickle.loads(pickled)
+        self.assertIs(unpickled.__orig_class__, thing.__orig_class__)
+        self.assertIs(unpickled.__orig_class__.__args__[0],
+                      Class5.meth.__type_params__[0])
+

 class TypeParamsWeakRefTest(unittest.TestCase):
    def test_weakrefs(self):

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-01-29-15-32-02.gh-issue-129250.ExhmQQ.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-01-29-15-32-02.gh-issue-129250.ExhmQQ.rst
@@ -0,0 +1 @@
+Fix pickling of generic classes instances.
@@ -8,7 +8,8 @@
 #include "internal/pycore_interp.h"
 #include "internal/pycore_typevarobject.h"
 #include "internal/pycore_unionobject.h"  // _PyUnion_Type
-#include "pycore_pystate.h"       // _PyInterpreterState_GET()
+#include "pycore_pystate.h"               // _PyInterpreterState_GET()
+#include "pycore_runtime.h"               // _Py_ID()
 #include "clinic/_typingmodule.c.h"

 /*[clinic input]
@@ -35,8 +36,34 @@ _typing__idfunc(PyObject *module, PyObject *x)
 }


+/*[clinic input]
+_typing._restore_anonymous_typeparam -> object
+
+    owner: object
+    index: object
+    /
+
+Restore previously pickled anonymous type param from object.__type_params__.
+[clinic start generated code]*/
+
+static PyObject *
+_typing__restore_anonymous_typeparam_impl(PyObject *module, PyObject *owner,
+                                          PyObject *index)
+/*[clinic end generated code: output=00baec27dbf8d2d9 input=2f048db28d8124fb]*/
+{
+    PyObject *type_params = PyObject_GetAttr(owner, &_Py_ID(__type_params__));
+    if (type_params == NULL) {
+        return NULL;
+    }
+    PyObject *res = PyObject_GetItem(type_params, index);
+    Py_DECREF(type_params);
+    return res;
+}
+
+
 static PyMethodDef typing_methods[] = {
    _TYPING__IDFUNC_METHODDEF
+    _TYPING__RESTORE_ANONYMOUS_TYPEPARAM_METHODDEF
    {NULL, NULL, 0, NULL}
 };