Index: modules/node/node.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/node/node.module,v
retrieving revision 1.783
diff -u -a -p -r1.783 node.module
--- modules/node/node.module	15 Feb 2007 11:40:18 -0000	1.783
+++ modules/node/node.module	23 Feb 2007 20:33:42 -0000
@@ -592,6 +592,9 @@ function node_save(&$node) {
     // message. A new revision will have an empty log message (or $node->log).
     $revisions_table_values['log'] = $node->log;
     $revisions_table_types['log'] = "'%s'";
+  } else {
+    $revisions_table_values['log'] = ''; // empty string value
+    $revisions_table_types['log'] = "'%s'";
   }
   $node_table_values = array('nid' => $node->nid, 'vid' => $node->vid,
                     'title' => $node->title, 'type' => $node->type, 'uid' => $node->uid,