+ # Prepend field_ to avoid conflicts with base fields, and make sure the
+ # result is no longer than 32 characters.
+ -
+ plugin: concat
+ source:
+ - constants/field_prefix
+ - '@raw_field_name'
+ -
+ plugin: substr
+ length: 32
+ -
+ # This plugin checks if the vocabulary being migrated is the one used by
+ # Forum. If so, we use the machine name that Forum expects. Otherwise, we
+ # leave it unchanged.
+ plugin: forum_vocabulary
+ machine_name: taxonomy_forums