Ticket #22884: 22884-handle_error.diff

trunk/src/wp-includes/wp-db.php

@@ -81 +81 @@
         public $last_error = '';
 
         /**
+         * The last error code during query
+         *
+         * @since 4.2.0
+         * @var int
+         */
+        public $last_error_no = 0;
+
+        /**
          * Amount of queries made
          *
          * @since 1.2.0
@@ -1233 +1241 @@
         }
 
         /**
+         * Handle SQL/DB error.
+         *
+         * This function adds the possibility to react to specific database errors
+         * Initial problem had to do with accidentally removed WP tables (causes: bad backup, user fault, etc)
+         * This allows for a check to verify all core tables are in place
+         *
+         * @since 4.2.0
+         * @access public
+         *
+         */
+        public function handle_error() {
+                if ( $this->suppress_errors || 0 == $this->last_error_no ) {
+                        return;
+                }
+
+                // Make sure the error is logged and optionally printed.
+                $this->print_error();
+
+
+                /*
+                 * Check for missing tables; only once per execution.
+                 * If this passes, some custom table is missing and we can't really do anything about that.
+                 */
+                static $wp_tables_verified = false;
+
+                /**
+                 * For all MySQL Error codes see:
+                 * http://dev.mysql.com/doc/refman/5.5/en/error-messages-server.html
+                 *
+                 * Implemented
+                 *  Error: 1146 SQLSTATE: 42S02 (ER_NO_SUCH_TABLE)
+                 *
+                 */
+                if ( false === $wp_tables_verified && 1146 == $this->last_error_no ) {
+                        $suppress = $this->suppress_errors();
+
+                        /*
+                         * Loop over the WP tables.
+                         * If one or more are missing, suggest table repair.
+                         *
+                         * Because we got this far, the global is_blog_installed() passed, so options table should be there.
+                         */
+                        $wp_tables = $this->tables();
+
+                        foreach ( $wp_tables as $table ) {
+                                // The existence of custom user tables shouldn't suggest an insane state or prevent a clean install.
+                                if ( defined( 'CUSTOM_USER_TABLE' ) && CUSTOM_USER_TABLE == $table )
+                                        continue;
+                                if ( defined( 'CUSTOM_USER_META_TABLE' ) && CUSTOM_USER_META_TABLE == $table )
+                                        continue;
+
+                                // If we have results, the table exists
+                                $sql_check = $this->prepare( "SHOW TABLES LIKE %s", $table );
+                                $table_exists = ( $this->get_var( $sql_check ) != null );
+                                if ( $table_exists ) {
+                                        continue;
+                                }
+
+                                // Recreate missing tables.
+                                require(ABSPATH . 'wp-admin/includes/upgrade.php');
+                                // Make sure we have the latest (and all) tables
+                                dbDelta();
+
+                                // We're done now, all missing tables should be restored
+                                break;
+                        }
+
+                        $this->suppress_errors( $suppress );
+
+                        $wp_tables_verified = true;
+                }
+
+        }
+
+        /**
          * Print SQL/DB error.
          *
          * @since 0.71
@@ -1352 +1435 @@
                 $this->last_query  = null;
                 $this->rows_affected = $this->num_rows = 0;
                 $this->last_error  = '';
+                $this->last_error_no = 0;
 
                 if ( $this->use_mysqli && $this->result instanceof mysqli_result ) {
                         mysqli_free_result( $this->result );
@@ -1642 +1726 @@
                         $this->last_error = mysql_error( $this->dbh );
                 }
 
+                $this->last_error_no = $mysql_errno;
+
                 if ( $this->last_error ) {
                         // Clear insert_id on a subsequent failed insert.
                         if ( $this->insert_id && preg_match( '/^\s*(insert|replace)\s/i', $query ) )
                                 $this->insert_id = 0;
 
-                        $this->print_error();
+                        $this->handle_error();
                         return false;
                 }