This is done by calling first the getter method for the parent language for the
terms that are not yet cached. After existing translations are set for the
language. And finally the result is stored in the cache.
The synchronisation wizard remove also the translations that are identical to
their parent language.
The method load_module_graph adds all parent languages to be loaded for
derivation.
issue5443
review25581002
Cédric Krier
d305c26e54