Re-add passing native methods the subclass instance

Fixes #8488

Author: tannewt

ports/unix/native_base_class.c

@@ -55,8 +55,24 @@ MP_PROPERTY_GETSET(native_base_class_test_obj,
     (mp_obj_t)&native_base_class_get_test_obj,
     (mp_obj_t)&native_base_class_set_test_obj);
 
+STATIC mp_obj_t native_base_class_obj_print_subclass_attr(mp_obj_t self_in, mp_obj_t attr_name_obj) {
+    if (!mp_obj_is_str(attr_name_obj)) {
+        mp_raise_TypeError(NULL);
+    }
+    qstr attr_name = mp_obj_str_get_qstr(attr_name_obj);
+    mp_obj_t value = mp_load_attr(self_in, attr_name);
+    mp_printf(&mp_plat_print, "native base class .%q set to: ", attr_name);
+    mp_obj_print_helper(&mp_plat_print, value, PRINT_REPR);
+    mp_printf(&mp_plat_print, "\n");
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_2(native_base_class_print_subclass_attr_obj, native_base_class_obj_print_subclass_attr);
+
 STATIC const mp_rom_map_elem_t native_base_class_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_test), MP_ROM_PTR(&native_base_class_test_obj) },
+
+    { MP_ROM_QSTR(MP_QSTR_print_subclass_attr), MP_ROM_PTR(&native_base_class_print_subclass_attr_obj) },
+
 };
 STATIC MP_DEFINE_CONST_DICT(native_base_class_locals_dict, native_base_class_locals_dict_table);
 

py/objstringio.c

@@ -45,15 +45,26 @@ STATIC void check_stringio_is_open(const mp_obj_stringio_t *o) {
 #define check_stringio_is_open(o)
 #endif
 
+STATIC mp_obj_stringio_t *native_obj(mp_obj_t o_in) {
+    mp_obj_stringio_t *native = mp_obj_cast_to_native_base(o_in, &mp_type_stringio);
+
+    #if MICROPY_PY_IO_BYTESIO
+    if (native == MP_OBJ_NULL) {
+        native = mp_obj_cast_to_native_base(o_in, &mp_type_bytesio);
+    }
+    #endif
+    return native;
+}
+
 STATIC void stringio_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     (void)kind;
-    mp_obj_stringio_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_obj_stringio_t *self = native_obj(self_in);
     mp_printf(print, self->base.type == &mp_type_stringio ? "<io.StringIO 0x%x>" : "<io.BytesIO 0x%x>", self);
 }
 
 STATIC mp_uint_t stringio_read(mp_obj_t o_in, void *buf, mp_uint_t size, int *errcode) {
     (void)errcode;
-    mp_obj_stringio_t *o = MP_OBJ_TO_PTR(o_in);
+    mp_obj_stringio_t *o = native_obj(o_in);
     check_stringio_is_open(o);
     if (o->vstr->len <= o->pos) {  // read to EOF, or seeked to EOF or beyond
         return 0;
@@ -77,7 +88,7 @@ STATIC void stringio_copy_on_write(mp_obj_stringio_t *o) {
 
 STATIC mp_uint_t stringio_write(mp_obj_t o_in, const void *buf, mp_uint_t size, int *errcode) {
     (void)errcode;
-    mp_obj_stringio_t *o = MP_OBJ_TO_PTR(o_in);
+    mp_obj_stringio_t *o = native_obj(o_in);
     check_stringio_is_open(o);
 
     if (o->vstr->fixed_buf) {
@@ -111,7 +122,7 @@ STATIC mp_uint_t stringio_write(mp_obj_t o_in, const void *buf, mp_uint_t size,
 
 STATIC mp_uint_t stringio_ioctl(mp_obj_t o_in, mp_uint_t request, uintptr_t arg, int *errcode) {
     (void)errcode;
-    mp_obj_stringio_t *o = MP_OBJ_TO_PTR(o_in);
+    mp_obj_stringio_t *o = native_obj(o_in);
     switch (request) {
         case MP_STREAM_SEEK: {
             struct mp_stream_seek_t *s = (struct mp_stream_seek_t *)arg;
@@ -163,7 +174,7 @@ STATIC mp_uint_t stringio_ioctl(mp_obj_t o_in, mp_uint_t request, uintptr_t arg,
 #define STREAM_TO_CONTENT_TYPE(o) (((o)->base.type == &mp_type_stringio) ? &mp_type_str : &mp_type_bytes)
 
 STATIC mp_obj_t stringio_getvalue(mp_obj_t self_in) {
-    mp_obj_stringio_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_obj_stringio_t *self = native_obj(self_in);
     check_stringio_is_open(self);
     // TODO: Try to avoid copying string
     return mp_obj_new_str_of_type(STREAM_TO_CONTENT_TYPE(self), (byte *)self->vstr->buf, self->vstr->len);

py/objtype.c

@@ -199,14 +199,9 @@ STATIC void mp_obj_class_lookup(struct class_lookup_data *lookup, const mp_obj_t
                     return;
                 } else {
                     mp_obj_instance_t *obj = lookup->obj;
-                    mp_obj_t obj_obj;
-                    if (obj != NULL && mp_obj_is_native_type(type) && type != &mp_type_object /* object is not a real type */) {
-                        // If we're dealing with native base class, then it applies to native sub-object
-                        obj_obj = obj->subobj[0];
-                    } else {
-                        obj_obj = MP_OBJ_FROM_PTR(obj);
-                    }
-                    mp_convert_member_lookup(obj_obj, type, elem->value, lookup->dest);
+                    // CIRCUITPY-CHANGE: Pass object directly. MP passes the native object.
+                    // This allows native code to lookup and call functions on Python subclasses.
+                    mp_convert_member_lookup(obj, type, elem->value, lookup->dest);
                 }
                 #if DEBUG_PRINT
                 DEBUG_printf("mp_obj_class_lookup: Returning: ");

tests/unix/subclass_native.py

@@ -29,6 +29,8 @@ class A(NativeBaseClass):
 a._new_attribute = True
 print("._new_attribute", a._new_attribute)
 
+a.print_subclass_attr("_new_attribute")
+
 
 class B(NativeBaseClass):
     def __init__(self, suffix):
@@ -43,3 +45,5 @@ def __init__(self, suffix):
 
 b._new_attribute = True
 print("._new_attribute", b._new_attribute)
+
+b.print_subclass_attr("_new_attribute")

tests/unix/subclass_native.py.exp

@@ -5,7 +5,9 @@ native base class .test set to: 'test set directly'
 native base class .test set to: 'test set indirectly'
 .test: test set indirectly
 ._new_attribute True
+native base class ._new_attribute set to: True
 .test: super init suffix
 native base class .test set to: 'test set indirectly through b'
 .test: test set indirectly through b
 ._new_attribute True
+native base class ._new_attribute set to: True