Changeset 38441

Timestamp:

08/30/2016 07:37:59 AM (10 years ago)

Author:

pento

Message:

Database: Don't force an unsupported character set that previously would've silently failed.

[37320] corrected some behaviour in how PHP and MySQL character sets are matched up. This was correct, but had the side effect of causing some incorrectly configured sites to start failing.

Prior to [37320], if DB_CHARSET was set to utf8mb4, but the PHP version didn't support utf8mb4, it would fall back to the default character set - usually latin1. After [37320], the SET NAMES query would force MySQL to treat the connection character set as utf8mb4, even if PHP wasn't able to understand it.

By checking if mysqli_set_charset() succeeded, we can simulate the old behaviour, while maintaining the fix in [37320].

Props danielkanchev fo helping to diagnose this issue.
Fixes #37689 for trunk.

File:

• trunk/src/wp-includes/wp-db.php (modified) (1 diff)

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

@@ -812 +812 @@
                         $collate = $this->collate;
                 if ( $this->has_cap( 'collation' ) && ! empty( $charset ) ) {
+                        $set_charset_succeeded = true;
+
                         if ( $this->use_mysqli ) {
                                 if ( function_exists( 'mysqli_set_charset' ) && $this->has_cap( 'set_charset' ) ) {
-                                        mysqli_set_charset( $dbh, $charset );
+                                        $set_charset_succeeded = mysqli_set_charset( $dbh, $charset );
                                 }
-                                $query = $this->prepare( 'SET NAMES %s', $charset );
-                                if ( ! empty( $collate ) )
-                                        $query .= $this->prepare( ' COLLATE %s', $collate );
-                                mysqli_query( $dbh, $query );
+
+                                if ( $set_charset_succeeded ) {
+                                        $query = $this->prepare( 'SET NAMES %s', $charset );
+                                        if ( ! empty( $collate ) )
+                                                $query .= $this->prepare( ' COLLATE %s', $collate );
+                                        mysqli_query( $dbh, $query );
+                                }
                         } else {
                                 if ( function_exists( 'mysql_set_charset' ) && $this->has_cap( 'set_charset' ) ) {
-                                        mysql_set_charset( $charset, $dbh );
+                                        $set_charset_succeeded = mysql_set_charset( $charset, $dbh );
                                 }
-                                $query = $this->prepare( 'SET NAMES %s', $charset );
-                                if ( ! empty( $collate ) )
-                                        $query .= $this->prepare( ' COLLATE %s', $collate );
-                                mysql_query( $query, $dbh );
+                                if ( $set_charset_succeeded ) {
+                                        $query = $this->prepare( 'SET NAMES %s', $charset );
+                                        if ( ! empty( $collate ) )
+                                                $query .= $this->prepare( ' COLLATE %s', $collate );
+                                        mysql_query( $query, $dbh );
+                                }
                         }
                 }