diff --git a/release/ui/space_script.py b/release/ui/space_script.py
index 0ab091e8fd5..d2c73adb00f 100644
--- a/release/ui/space_script.py
+++ b/release/ui/space_script.py
@@ -112,7 +112,7 @@ class SCRIPT_OT_reload_scripts(bpy.types.Operator):
                     register_op(cls)
                     print("Registered it.")
 
-        return 'FINISHED'
+        return ('FINISHED',)
 
     def invoke(self, context, event):
         print("SCRIPT_OT_reload_scripts: invoke")
diff --git a/source/blender/python/intern/bpy_operator_wrap.c b/source/blender/python/intern/bpy_operator_wrap.c
index 33715a97a43..4624fe764b3 100644
--- a/source/blender/python/intern/bpy_operator_wrap.c
+++ b/source/blender/python/intern/bpy_operator_wrap.c
@@ -316,7 +316,8 @@ static int PYTHON_OT_generic(int mode, bContext *C, wmOperator *op, wmEvent *eve
 		} else if (BPY_flag_from_seq(pyop_ret_flags, ret, &ret_flag) == -1) {
 			 /* the returned value could not be converted into a flag */
 			pyop_error_report(op->reports);
-			
+
+			ret_flag = OPERATOR_CANCELLED;
 		}
 		/* there is no need to copy the py keyword dict modified by
 		 * pyot->py_invoke(), back to the operator props since they are just
@@ -329,6 +330,29 @@ static int PYTHON_OT_generic(int mode, bContext *C, wmOperator *op, wmEvent *eve
 		Py_DECREF(ret);
 	}
 
+	/* print operator return value */
+	if (mode != PYOP_POLL) {
+		char flag_str[100];
+		char class_name[100];
+		BPY_flag_def *flag_def = pyop_ret_flags;
+
+		strcpy(flag_str, "");
+		
+		while(flag_def->name) {
+			if (ret_flag & flag_def->flag) {
+				flag_str[1] ? sprintf(flag_str, "%s | %s", flag_str, flag_def->name) : strcpy(flag_str, flag_def->name);
+			}
+			flag_def++;
+		}
+
+		/* get class name */
+		item= PyObject_GetAttrString(py_class, PYOP_ATTR_IDNAME);
+		Py_DECREF(item);
+		strcpy(class_name, _PyUnicode_AsString(item));
+
+		fprintf(stderr, "%s's %s returned %s\n", class_name, mode == PYOP_EXEC ? "exec" : "invoke", flag_str);
+	}
+
 	PyGILState_Release(gilstate);
 
 	return ret_flag;
diff --git a/source/blender/python/intern/bpy_util.c b/source/blender/python/intern/bpy_util.c
index 8dd81834213..2c7626fea7f 100644
--- a/source/blender/python/intern/bpy_util.c
+++ b/source/blender/python/intern/bpy_util.c
@@ -109,6 +109,9 @@ int BPY_flag_from_seq(BPY_flag_def *flagdef, PyObject *seq, int *flag)
 		error_val= 1;
 	}
 
+	if (*flag == 0)
+		error_val = 1;
+
 	if (error_val) {
 		char *buf = bpy_flag_error_str(flagdef);
 		PyErr_SetString(PyExc_AttributeError, buf);