My Drupal language prefixes are not just 2 letter codes, but things like "en-EA, fr-CA, and others".

This limitation is not needed and breaks things:
Each custom IP 2 Locale map must be in the format 'cc,lc' (ISO 3166 2-character Country Code to Drupal Language Code) eg.
'ie,en' (Ireland to English)
'us,en' (United States to English)
The following mappings are invalid:

I'll patch locally.

Comments

Gabriel R.’s picture

Gabriel R. commented
Status: Active » Closed (cannot reproduce)

Sorry, I think this was caused by a line break at the end.