Ticket #54987: 54987.3.diff

src/wp-includes/user.php

@@ -1977 +1977 @@
          */
         if ( ! empty( $userdata['user_nicename'] ) ) {
                 $user_nicename = sanitize_user( $userdata['user_nicename'], true );
-                if ( mb_strlen( $user_nicename ) > 50 ) {
-                        return new WP_Error( 'user_nicename_too_long', __( 'Nicename may not be longer than 50 characters.' ) );
-                }
         } else {
                 $user_nicename = mb_substr( $user_login, 0, 50 );
         }
@@ -1995 +1992 @@
          */
         $user_nicename = apply_filters( 'pre_user_nicename', $user_nicename );
 
+        if ( mb_strlen( $user_nicename ) > 50 ) {
+                return new WP_Error( 'user_nicename_too_long', __( 'Nicename may not be longer than 50 characters.' ) );
+        }
+
         $user_nicename_check = $wpdb->get_var( $wpdb->prepare( "SELECT ID FROM $wpdb->users WHERE user_nicename = %s AND user_login != %s LIMIT 1", $user_nicename, $user_login ) );
 
         if ( $user_nicename_check ) {