Ticket #44921: 44921.2.diff

src/wp-includes/user.php

@@ -1419 +1419 @@
 }
 
 /**
+ * Determines whether the given user_nicename exists.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 5.1.0
+ *
+ * @param string $nicename Nicename.
+ * @param string $login (Optional) User login to compare against.
+ * @return int|false The user's ID on success, and false on failure.
+ */
+function nicename_exists( $nicename, $login = false ) {
+        $user_id = false;
+        if ( $user = get_user_by( 'slug', $user_nicename ) ) {
+                if ( $login !== $user->user_login ){
+                        $user_id = $user->ID;
+                }
+        }
+
+        return $user_id;
+}
+
+
+/**
  * Checks whether a username is valid.
  *
  * @since 2.0.1
@@ -1710 +1735 @@
 
         $meta['locale'] = isset( $userdata['locale'] ) ? $userdata['locale'] : '';
 
-        $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 ) );
+        $user_nicename_check = nicename_exists( $user_nicename, $user_login );
 
         if ( $user_nicename_check ) {
                 $suffix = 2;
@@ -1718 +1743 @@
                         // user_nicename allows 50 chars. Subtract one for a hyphen, plus the length of the suffix.
                         $base_length         = 49 - mb_strlen( $suffix );
                         $alt_user_nicename   = mb_substr( $user_nicename, 0, $base_length ) . "-$suffix";
-                        $user_nicename_check = $wpdb->get_var( $wpdb->prepare( "SELECT ID FROM $wpdb->users WHERE user_nicename = %s AND user_login != %s LIMIT 1", $alt_user_nicename, $user_login ) );
+                        $user_nicename_check = nicename_exists( $alt_user_nicename, $user_login );
                         $suffix++;
                 }
                 $user_nicename = $alt_user_nicename;