add_filter return value

Question

function validate_username( $username ) {
    $sanitized = sanitize_user( $username, true );
    $valid = ( $sanitized == $username );

    return apply_filters( 'validate_username', $valid, $username );
}

in wp-includes/registration.php i want to change

$sanitized = sanitize_user( $username, true );

to

$sanitized = sanitize_user( $username, false );

I couldnt success to write add_filter in there, somehow its not working. Can you write a filter for this please?

Answer 1

Like so:

function my_validate_username( $valid, $username ) {
    $sanitized = sanitize_user( $username, false );
    $valid = ( $sanitized == $username );

    return $valid;
}

add_filter('validate_username', 'my_validate_username', 10, 2);

Answer 2

Overriding the filter does not work, it causes the error described by Ünsal. Has anybody actually got this working? Not sure how to trace, but it looks like the error is cause somewere in the registration process as a result of the non-latin username.

Answer 3

So the problem is caused by this line in wp-includes/user.php:

$user_login = sanitize_user($user_login, true);

which causes sanitize_true to be strict, which reduced to ascii.

Change to false to work around, who knows what other bugs this will cause since apparently non-latin logins in wordpress is not supported, see this thread:

http://bbpress.org/forums/topic/accents-in-username#post-19037