Ticket #7391: 7391.r8483.diff

Index: pluggable.php
===================================================================
--- pluggable.php       (revision 8483)
+++ pluggable.php       (working copy)
@@ -1512,9 +1512,17 @@
        $defaults = array( 'title' => '', 'title_left' => '', 'title_right' => '' );
        $args = wp_parse_args( $args, $defaults );
 
-       // PEAR Text_Diff is lame; it includes things from include_path rather than it's own path.
-       // Not sure of the ramifications of disttributing modified code.
-       ini_set('include_path', '.' . PATH_SEPARATOR . ABSPATH . WPINC );
+       // PEAR Text_Diff depends on the include path matching its directory structure.
+       // This prevents modifying source code and maintaining the modifications when
+       // the package is updated.
+       // If include_path can not be set, then bail.
+       if( function_exists('set_include_path') ) {
+               set_include_path( get_include_path() . PATH_SEPARATOR . ABSPATH . WPINC );
+       } else if( function_exists('ini_set') ) {
+               ini_set('include_path', '.' . PATH_SEPARATOR . ABSPATH . WPINC );
+       } else {
+               return __('Error: Setting the include path is disabled on your server. Post revisions cannot be displayed. Please contact your hosting company to resolve this error.');
+       }
 
        if ( !class_exists( 'WP_Text_Diff_Renderer_Table' ) )
                require( ABSPATH . WPINC . '/wp-diff.php' );
@@ -1534,7 +1542,11 @@
        $renderer  = new WP_Text_Diff_Renderer_Table();
        $diff = $renderer->render($text_diff);
 
-       ini_restore('include_path');
+       if( function_exists('restore_include_path') ) {
+               restore_include_path();
+       } else if( function_exists('ini_restore') ) {
+               ini_restore('include_path');
+       }
 
        if ( !$diff )
                return '';