Index: modules/update/update.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/update/update.module,v
retrieving revision 1.70
diff -u -p -r1.70 update.module
--- modules/update/update.module	6 Oct 2010 13:36:30 -0000	1.70
+++ modules/update/update.module	23 Nov 2010 17:08:22 -0000
@@ -336,6 +336,19 @@ function update_form_system_modules_alte
 }
 
 /**
+ * Implements hook_verify_update_archive().
+ */
+function update_verify_update_archive($project, $archive_file, $directory) {
+  $failures = array();
+  // If the package contains Drupal core, throw an exception.
+  if (file_exists("$directory/$project/includes/bootstrap.inc")) {
+    $failure[$archive_file] = 'core';
+    throw new Exception(t('Automatic updating of Drupal core is not supported. See the <a href="@upgrade-guide">upgrade guide</a> for information on how to update Drupal core manually.', array('@upgrade-guide' => 'http://drupal.org/upgrade')));
+  }
+  return $failures;
+}
+
+/**
  * Helper function for use as a form submit callback.
  */
 function update_cache_clear_submit($form, &$form_state) {