0002-replace-username-with-email.md

0002 - Replace user name by e-mail address

Status

Accepted

Summary

Users shall be uniquely identified by an e-mail address only.

Context

Currentrly existing users are identified by both a user name and an e-mail address. Only the user name is guaranteed to be unique, but not the e-mail address.

The database already contains different users for the same e-mail address:

select id, role, username, email, email_confirmed
from users
where email in (select email from users group by email having count(*) > 1)
order by email;

Users are able to provide either the user name or the e-mail address and all database queries have to account for this duality.

For new users the user name is already generated from the e-mail address and cannot be chosen. The user name has become redundant and could be replaced by the e-mail address.

Decision

Use the e-mail address for identifying users:

• Merge users with the same e-mail address into a single user
• Prevent duplicate e-mail addresses in the future
• Replace all references of username by email
• Remove username from the database and the code base

Consequences

Advantages

Cleaning up the database and using the e-mail address as the a unique identifier for users simplifies the implementation and prevents errors, e.g. when resetting passwords kartevonmorgen #539.

Drawbacks

Subscriptions for redundant user names are deleted, i.e. only a single subscription for each user ()= e-mail address) will be supported.