Ticket #21663: 21663.18.diff

src/wp-includes/wp-db.php

@@ -549 +549 @@
         private $use_mysqli = false;
 
         /**
+         * Whether we've managed to successfully connect at some point
+         *
+         * @since 3.9.0
+         * @access private
+         * @var bool
+         */
+        private $has_connected = false;
+
+        /**
          * Connects to the database server and selects a database
          *
          * PHP5 style constructor for compatibility with PHP5. Does
@@ -1336 +1345 @@
 
                         if ( $this->dbh->connect_errno ) {
                                 $this->dbh = null;
+
+                                /* Try to fallback to ext/mysql if:
+                                 *  - We haven't previously connected, and
+                                 *  - USE_EXT_MYSQL isn't set to false, and
+                                 *  - ext/mysql is loaded.
+                                 */
+                                $attempt_fallback = true;
+
+                                if ( $this->has_connected ) {
+                                        $attempt_fallback = false;
+                                } else if ( defined( 'USE_EXT_MYSQL' ) && USE_EXT_MYSQL ) {
+                                        $attempt_fallback = false;
+                                } else if ( ! function_exists( 'mysql_connect' ) ) {
+                                        $attempt_fallback = false;
+                                }
+
+                                if ( $attempt_fallback ) {
+                                        $this->use_mysqli = false;
+                                        $this->db_connect();
+                                }
                         }
                 } else {
                         if ( WP_DEBUG ) {
@@ -1367 +1396 @@
 
                         return false;
                 } else if ( $this->dbh ) {
+                        $this->has_connected = true;
                         $this->set_charset( $this->dbh );
                         $this->set_sql_mode();
                         $this->ready = true;