Duplicate entry

It works for me! Thanks @gaydamaka.
I also agree that direct request to the database is very light

but I think to use a user_load_by_name function is better by two reasons:
- This function gets an Entity Storage service which is Entity Storage Interface implementation.
- This solves possible problems in case User Storage will be overridden by one of the modules.

but another side this function load a fully-loaded user object that is not really needed for us in this case.

We always always always need to use the drupal API.

I am unable to reproduce this error.

However, looking at patch #2, I started wondering whether the following instruction should be used in the function realname_update() at all?

$account->setUsername($realname);

Whatever I'm trying here I cannot reproduce the SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry. It's nearly impossible to know what user is the right one, but it all works without errors. Can you document the repro, please?

There may be a simple solution here. Something already done in D7.

'value' => t('@realname (@id)', ['@realname' => $account->getDisplayName(), '@id' => $account->id()]),
'label' => t('@realname', ['@realname' => $account->getDisplayName()]),

We may change label to show the username or ID in brackets. In D7 it was the username.

With ID:

'value' => t('@realname (@id)', ['@realname' => $account->getDisplayName(), '@id' => $account->id()]),
'label' => t('@realname (@id)', ['@realname' => $account->getDisplayName(), '@id' => $account->id()]),

and with username (I think this is better usability than just a number):

'value' => t('@realname (@id)', ['@realname' => $account->getDisplayName(), '@id' => $account->id()]),
'label' => t('@realname (@username)', ['@realname' => $account->getDisplayName(), '@username' => $account->getAccountName()]),

This would be just a usability enhancement, not a solution for the SQL issue reported.

getAccountName() returns empty value on Anonymous. Need to investigate.

Above changes are in RC1 and opened a follow up #2881524: getAccountName() returns no username for Anonymous user.

As I'm not able to repro the duplicate entry situation, I'm closing as cannot repro. If you know - how to repro, please reopen with step by step instructions.