Add option to create-user to disallow numeric increases in usernames

Problem to solve

If you have external auth defined, users can end up creating multiple accounts ending with user.last, user.last1, user.last2, user.last3 ... etc.

Intended users

Administrator, idM

Further details

n/a

Proposal

Add an option to external auth to auto-create users, but disallow duplicate username numerical increments, and show an error to let the user know that the userid has already been used and to contact administrator. Obviously this feature would be disabled by default but for those who know they're going through a change or switching auth providers.

Permissions and Security

Admin function only

Documentation

Testing

It isn't "less" work by administrator, but it will allow a clean built system without duplicate users ... specially when they inevitably require something, urgently, from the old profile to be moved over and screw up history.

What does success look like, and how can we measure that?

Less headaches, and a clean system.

Links / references