py: Implement support for generalized generator protocol.

Iterators and ducktype objects can now be arguments of yield from.

1 files changed, 8 insertions, 1 deletions

diff --git a/py/objgenerator.c b/py/objgenerator.c
index d1bae30de..c3d7f12d7 100644
--- a/py/objgenerator.c
+++ b/py/objgenerator.c
@@ -135,7 +135,14 @@ STATIC mp_obj_t gen_resume_and_raise(mp_obj_t self_in, mp_obj_t send_value, mp_o
             return ret;
 
         case MP_VM_RETURN_EXCEPTION:
-            nlr_jump(ret);
+            // TODO: Optimization of returning MP_OBJ_NULL is really part
+            // of mp_iternext() protocol, but this function is called by other methods
+            // too, which may not handled MP_OBJ_NULL.
+            if (mp_obj_is_subclass_fast(mp_obj_get_type(ret), &mp_type_StopIteration)) {
+                return MP_OBJ_NULL;
+            } else {
+                nlr_jump(ret);
+            }
 
         default:
             assert(0);