The check in resources/src/mediawiki.special/mediawiki.special.userlogin.signup.js that attempts to help the user choose an available username is not aware of CentralAuth accounts that have not been attached to the local wiki. This is due to the use of /w/api.php?action=query&list=users to power the check.
Example:
- http://en.wikipedia.org/w/api.php?action=query&list=users&ususers=BryanDavis
- http://fr.wikipedia.org/w/api.php?action=query&list=users&ususers=BryanDavis
The conflict will be noticed when the form is submitted, but it would be nicer if users were warned about global user conflicts by the pre-submit validation.
Version: 1.24rc
Severity: enhancement
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=64728