Index: modules/node/node.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/node/node.module,v
retrieving revision 1.947.2.13
diff -u -F^function -r1.947.2.13 node.module
--- modules/node/node.module	14 Jan 2009 23:34:07 -0000	1.947.2.13
+++ modules/node/node.module	20 Jan 2009 22:00:27 -0000
@@ -886,6 +886,13 @@ function node_save(&$node) {
   }
   elseif (!empty($node->revision)) {
     $node->old_vid = $node->vid;
+
+    if (!isset($node->teaser)) {
+      $node->teaser = '';
+    }
+    if (!isset($node->body)) {
+      $node->body = '';
+    }    
   }
   else {
     // When updating a node, avoid clobberring an existing log entry with an empty one.