WPDB: When we're checking to see if the MySQL client library supports `utf8mb4`, we need a separate check for `mysqlnd` versions, which using different version numbering to `libmysqlclient`.

Props MattyRob.

Fixes #31644.


Built from https://develop.svn.wordpress.org/trunk@31939


git-svn-id: http://core.svn.wordpress.org/trunk@31918 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-beta3-31938';
+$wp_version = '4.2-beta3-31939';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.

wp-includes/wp-db.php

@@ -2810,7 +2810,16 @@ class wpdb {
 					$client_version = mysql_get_client_info();
 				}
 
-				return version_compare( $client_version, '5.5.3', '>=' );
+				/*
+				 * libmysql has supported utf8mb4 since 5.5.3, same as the MySQL server.
+				 * mysqlnd has supported utf8mb4 since 5.0.9.
+				 */
+				if ( false !== strpos( $client_version, 'mysqlnd' ) ) {
+					$client_version = preg_replace( '/^\D+([\d.]+).*/', '$1', $client_version );
+					return version_compare( $client_version, '5.0.9', '>=' );
+				} else {
+					return version_compare( $client_version, '5.5.3', '>=' );
+				}
 		}
 
 		return false;