rb_imemo_class_fields_ptr handle empty fields

Author: byroot

gc.c

@@ -3813,7 +3813,6 @@ update_classext(rb_classext_t *ext, bool is_prime, VALUE namespace, void *arg)
 
     update_m_tbl(objspace, RCLASSEXT_M_TBL(ext));
 
-
     if (ext->fields_obj) {
         UPDATE_IF_MOVED(objspace, ext->fields_obj);
 

internal/imemo.h

@@ -284,7 +284,10 @@ VALUE rb_imemo_class_fields_new_complex(VALUE klass, st_table *tbl);
 static inline VALUE *
 rb_imemo_class_fields_ptr(VALUE obj_fields)
 {
-    RUBY_ASSERT(obj_fields);
+    if (!obj_fields) {
+        return NULL;
+    }
+
     RUBY_ASSERT(IMEMO_TYPE_P(obj_fields, imemo_class_fields));
 
     if (RB_UNLIKELY(FL_TEST_RAW(obj_fields, OBJ_FIELD_EXTERNAL))) {