Last modified: 2014-08-10 23:40:38 UTC
A new Wiki user is created and linked to a Google account. If this user is now deleted by UserMerge extension the reference within the user_google_user table doesn't match as it's not deleted automatically by another extension (UserMerge in this case). Afterwards it's not possible to login again another/new user until the whole table is deleted or this specific user entry. The user is always redirected to the main wiki page with status "not login". That means "Login" is still available in the upper right corner of MW. The table must be created again if it's deleted completely in the step before.
Change 148108 had a related patch set uploaded by Florianschmidtwelzow: WIP: Extended Login-workflow https://gerrit.wikimedia.org/r/148108
Change 148108 merged by jenkins-bot: Extended Login-workflow https://gerrit.wikimedia.org/r/148108
@Mike: Can you please verify, that this helps in your problem? :) Just load the extension new please.
@Mike: I will set this as fixed, if you have still problems, feel free to reopen.