Allow update __class__ for module subclasses

moreal · moreal · commit e17f3036dc21 · 2024-04-13T14:37:27.000+09:00
diff --git a/vm/src/builtins/object.rs b/vm/src/builtins/object.rs
@@ -281,7 +281,10 @@ impl PyBaseObject {
 
     #[pygetset(name = "__class__", setter)]
     fn set_class(instance: PyObjectRef, value: PyObjectRef, vm: &VirtualMachine) -> PyResult<()> {
-        if instance.payload_is::<PyBaseObject>() {
+        if instance.payload_is::<PyBaseObject>()
+            || (instance.class().fast_issubclass(vm.ctx.types.module_type)
+                && value.class().fast_issubclass(vm.ctx.types.module_type))
+        {
             match value.downcast::<PyType>() {
                 Ok(cls) => {
                     // FIXME(#1979) cls instances might have a payload
@@ -298,7 +301,8 @@ impl PyBaseObject {
             }
         } else {
             Err(vm.new_type_error(
-                "__class__ assignment only supported for types without a payload".to_owned(),
+                "__class__ assignment only supported for mutable types or ModuleType subclasses"
+                    .to_owned(),
             ))
         }
     }
