Change the database schema for the User entity and add a unique key for the email

Try to fixed #39 Cc Failed

Fixed #41 Cc Failed.

+    $random_generator = new Random();
 
     $edit = [];

The UserRegistrationTest class has the randomMachineName() and the randomString() methods. Using the Random class should not be necessary.

I still stand by my comment from #23.

I dont think we should be enforcing database level uniqueness, defer to validators and contrib to solve these issues.

Shall we get a framework maintainer opinion on this? (currently: Moshe)

I think there are still some unresolved questions, for example the one from #27:

What will occur if there are duplicates when the schema change is implemented?

It is also important to think about case-sensitivity. In MySQL unique columns are case insensitive by default, so you cannot have test@test.com and TEST@test.com. On the other side, in PostgreSQL, these are case sensitive and by default it will allow test@test.com and TEST@test.com in the unique columns. This can cause another confusion if not handled properly.

In my opinion, the uniqueness validation could remain only in code. There are lot of contrib modules creating weird email addresses just to workaround the need of the email address, or even saving empty email addresses and this change could potentially break all these.

Should we get rid of all other database constraints as well then?
Why do we unique constraints for UUID or username?

Seems like maybe we need to define a decision making criteria for when database constraints are warranted.

Hi all - user module maintainer here.

If I were designing Drupal from scratch, I would certainly put a uniqueness constraint in the DB. But we are now 22 years into Drupal's life, and I think that ship has sailed. We dont want to disrupt existing sites so much. Folks who want to add this constraint to their DB are free to do so via schema alter. See UserStorageSchema::getEntitySchema().

Lets focus improving our add/edit validators as needed. And lets do that in other issues.

I respectfully close this long-standing issue.

I think this functionality would be great for a contrib module.