2089200 - Enforce unique nicknames with a UNIQUE index on profiles.nickname

Status: ASSIGNED

(bugzilla.mozilla.org :: General, enhancement)

Description

[David Lawrence [:dkl]]

• Nickname uniqueness is enforced only in Perl (_generate_nickname, Bugzilla/User.pm:483). The schema has a plain index, and accounts without a nickname store '' as the default.
• Production had zero duplicate nicknames on 2026-11-04, so an index can be added without cleaning up data first.
• Plan:
  a. Make nickname nullable and convert '' to NULL in Install/DB.pm.
  b. Have _generate_nickname return undef instead of ''.
  c. Add a UNIQUE index (MySQL allows many NULLs).
  d. Catch the duplicate-key error from simultaneous nickname claims and fall back to no nickname.
• Check _migrate_nicknames (NOT nickname never matches NULL) and any callers comparing nicknames with ''.
• Follow-up: once the index exists, _users_for_mentions and mention-autocomplete.js no longer need their duplicate handling.
• Should block the mentions tracking bug 2085134.

Comment 1

[BMO Github Automation]

Attachment: [mozilla/bmo] Bug 2089200 - Enforce unique nicknames with a UNIQUE index on profiles.nickname (#2815)

(via GitHub webhook, authenticated as shared-secret)