Work around optimization bug

For some reason, the compiler is optimizing out a memset() that
clears the yaml_event_t at the end of yaml_event_delete(), which
is called implicitly by yaml_emitter_emit(). As a result, the
cleanup at the end of the function ends up performing a
double-free.

This works around the problem by always assuming that the
yaml_event_delete() routine worked properly and just forces the
event.type field to zero, thereby preventing any future calls to
yaml_event_delete() from attempting to free() memory.

Signed-off-by: Stephen Gallagher <[email protected]>

Author: sgallagher

modulemd/include/modulemd-1.0/private/modulemd-yaml.h

@@ -124,8 +124,11 @@ typedef gboolean (*ModulemdParsingFunc) (yaml_parser_t *parser,
 #define MMD_EMIT_WITH_EXIT(emitter, event, _error, ...)                       \
   do                                                                          \
     {                                                                         \
+      int _ret;                                                               \
       g_debug ("Emitter event: %s", mmd_yaml_get_event_name ((event)->type)); \
-      if (!yaml_emitter_emit (emitter, event))                                \
+      _ret = yaml_emitter_emit (emitter, event);                              \
+      (event)->type = 0;                                                      \
+      if (!_ret)                                                              \
         {                                                                     \
           g_debug (__VA_ARGS__);                                              \
           g_set_error (_error,                                                \