Ticket #7392: 7392-autosave.patch

wp-admin/includes/post.php

@@ -1267 +1267 @@
  * @return unknown
  */
 function wp_create_post_autosave( $post_id ) {
+        if ( ! $post = get_post( $post_id ) )
+                return;
+
         $translated = _wp_translate_postdata( true );
         if ( is_wp_error( $translated ) )
                 return $translated;
 
         $post_author = get_current_user_id();
+        $new_data = $_POST;
 
         // Store one autosave per author. If there is already an autosave, overwrite it.
         if ( $old_autosave = wp_get_post_autosave( $post_id, $post_author ) ) {
                 $new_autosave = _wp_post_revision_fields( $_POST, true );
                 $new_autosave['ID'] = $old_autosave->ID;
                 $new_autosave['post_author'] = $post_author;
-                return wp_update_post( $new_autosave );
+
+                $new_data = $new_autosave;
         }
 
+        if ( apply_filters( 'wp_save_post_revision_check_for_changes', true, $post, $new_data ) && is_array( $new_data ) ) {
+                $post_has_changed = false;
+                foreach ( array_keys( _wp_post_revision_fields() ) as $field ) {
+                        if ( normalize_whitespace( $new_data[ $field ] ) != normalize_whitespace( $post[ $field ] ) ) {
+                                $post_has_changed = true;
+                                break;
+                        }
+                }
+                //don't save revision if post unchanged
+                if( ! $post_has_changed )
+                        return;
+        }
+
+        if ( isset( $new_autosave ) )
+                return wp_update_post( $new_autosave );
+
         // _wp_put_post_revision() expects unescaped.
         $_POST = wp_unslash($_POST);