We are using email addresses as usernames in a current WP 3.1 project. I need to allow users to change their usernames and email addresses, and will build in the option to do so.
I am just wondering why this is not allowed by default in WP?
What can go wrong if I let our users change their passwords?
The problem with changing usernames is that it's a caching issue and that it breaks /author/username URLs.
The URL breaking issue is obvious.
The caching issue is less obvious. If you're using a persistent object cache like memcached or something, then the username will be stored in that cache, and thus it won't change properly until the cache runs out.
On a simple site setup, this doesn't happen because it doesn't have persistent object caching. On a complex one, it becomes a real problem. A fair number of changes to the user system would be needed to allow the caching to be taken care of properly.
A core feature request was rejected for this because of the limited need for it, basically. However, a core patch to correct the caching issue might be better considered, allowing for a much simpler plugin to change the username (or a simple patch to allow same, once the caching issue is cleared up).
Reference: http://core.trac.wordpress.org/ticket/14644
user_login and the user_nicename, which is used to create the URLs? If you change the login without changing the nicename, the URL would not change.
Commented
Mar 23, 2011 at 21:26