Ticket #17793: 17793.diff

wp-login.php

@@ -298 +298 @@
         if ( $sanitized_user_login == '' ) {
                 $errors->add( 'empty_username', __( '<strong>ERROR</strong>: Please enter a username.' ) );
         } elseif ( ! validate_username( $user_login ) ) {
-                $errors->add( 'invalid_username', __( '<strong>ERROR</strong>: This username is invalid because it uses illegal characters. Please enter a valid username.' ) );
+                $errors->add( 'invalid_username', __( '<strong>ERROR</strong>: This username is invalid because it uses illegal characters. Please enter a valid username. Usernames may contain only letters (a-z), numbers (0-9), dashes (-), underscores (_), and periods (.).' ) );
                 $sanitized_user_login = '';
         } elseif ( username_exists( $sanitized_user_login ) ) {
                 $errors->add( 'username_exists', __( '<strong>ERROR</strong>: This username is already registered, please choose another one.' ) );

wp-admin/includes/user.php

@@ -161 +161 @@
                 $user->user_pass = $pass1;
 
         if ( !$update && isset( $_POST['user_login'] ) && !validate_username( $_POST['user_login'] ) )
-                $errors->add( 'user_login', __( '<strong>ERROR</strong>: This username is invalid because it uses illegal characters. Please enter a valid username.' ));
+                $errors->add( 'user_login', __( '<strong>ERROR</strong>: This username is invalid because it uses illegal characters. Please enter a valid username. Usernames may contain only letters (a-z), numbers (0-9), dashes (-), underscores (_), and periods (.).' ));
 
         if ( !$update && username_exists( $user->user_login ) )
                 $errors->add( 'user_login', __( '<strong>ERROR</strong>: This username is already registered. Please choose another one.' ));