py/runtime: Fix handling of throw() when resuming generator.

If GeneratorExit is injected as a throw-value then that should lead to
the close() method being called, if it exists.  If close() does not exist
then throw() should not be called, and this patch fixes this.

1 files changed, 9 insertions, 7 deletions

diff --git a/py/runtime.c b/py/runtime.c
index a80ddca64..4a51c00b5 100644
--- a/py/runtime.c
+++ b/py/runtime.c
@@ -1245,13 +1245,15 @@ mp_vm_return_kind_t mp_resume(mp_obj_t self_in, mp_obj_t send_value, mp_obj_t th
                 // We assume one can't "yield" from close()
                 return MP_VM_RETURN_NORMAL;
             }
-        }
-        mp_load_method_maybe(self_in, MP_QSTR_throw, dest);
-        if (dest[0] != MP_OBJ_NULL) {
-            *ret_val = mp_call_method_n_kw(1, 0, &throw_value);
-            // If .throw() method returned, we assume it's value to yield
-            // - any exception would be thrown with nlr_raise().
-            return MP_VM_RETURN_YIELD;
+        } else {
+            mp_load_method_maybe(self_in, MP_QSTR_throw, dest);
+            if (dest[0] != MP_OBJ_NULL) {
+                dest[2] = throw_value;
+                *ret_val = mp_call_method_n_kw(1, 0, dest);
+                // If .throw() method returned, we assume it's value to yield
+                // - any exception would be thrown with nlr_raise().
+                return MP_VM_RETURN_YIELD;
+            }
         }
         // If there's nowhere to throw exception into, then we assume that object
         // is just incapable to handle it, so any exception thrown into it