Unhelpful wp_get_attachment_url filter
|Reported by:||filosofo||Owned by:||filosofo|
wp_get_attachment_url() returns false if it can't find a URL for that attachment, before the filter gets applied.
Obviously this isn't helpful for someone who's trying to address a missing URL via the filter.
There's no backwards-compatibility issue in the patch because it changes behavior only for those who are handling an empty URL via the filter.