Single login specifications

This page is meant as a formal set of specifications including workflows and GUI mock-ups for the transition to a single login system. Brion VIBBER is committed to this project, and work on it is scheduled to begin after the release of MediaWiki 1.5. However, this page is currently just a proposal, and needs to be developed in consensus before it should be considered anywhere near final.

General caveats

All user passwords are presently hashed and salted. Therefore, no two password hashes across different projects or languages are identical. This makes comparing existing accounts more difficult, though with user interaction, the passwords can of course be compared.
With a global account system, existing signatures on talk pages and in votes may point to the wrong account name after a migration.

Process

A new shared user account table will be created.
Accounts with associated e-mail addresses that are unique (i.e. there are no accounts on any Wikimedia project with the same username and a different e-mail address) are migrated transparently to the new table. The users receive a notification e-mail to this effect.
After date X (the migration date), all existing login sessions will expire.
The login screen will state unambiguously that unless you have received a notification e-mail, you will have to create a new account, and that you will be able to migrate your existing accounts to the new system. Local accounts will cease working.
After the first login, the user sees a new screen where they can enter a password for their existing accounts from any Wikimedia database. Any account they successfully authenticate against will be merged into theirs. This screen should continue to be accessible through the user preferences.

Trolls blocking account names should be dealt with on a case by case basis. (An alternative would be to factor in edit counts during the transparent migration.)

Transition period

After a transition period of 6 months, all remaining local accounts will be converted to the new system using the account name syntax "Username@wiki", e.g. "Eloquence@wp-en".

Migration

In the context of MediaWiki, migrating an account means that existing edits in local databases have to be attributed to the global account ID instead of the local one. One way to do this is to make sure that all global IDs are much higher than the highest local ID. While the new database schema somewhat eases the conversion, migrating a highly active account will still take some time. It might be best to create a batch of conversions to be done and process them sequentially.

GUI mock-ups

To be done.