2 files changed, 7 insertions, 1 deletions
diff --git a/modules/user/user.install b/modules/user/user.install
index 610d3d566..2b93e4e68 100644
--- a/modules/user/user.install
+++ b/modules/user/user.install
@@ -102,10 +102,11 @@ function user_schema() {
     'description' => 'Stores user data.',
     'fields' => array(
       'uid' => array(
-        'type' => 'serial',
+        'type' => 'int',
         'unsigned' => TRUE,
         'not null' => TRUE,
         'description' => 'Primary Key: Unique user ID.',
+        'default' => 0,
       ),
       'name' => array(
         'type' => 'varchar',
diff --git a/modules/user/user.module b/modules/user/user.module
index fe75f1c7b..48140a862 100644
--- a/modules/user/user.module
+++ b/modules/user/user.module
@@ -448,6 +448,11 @@ function user_save($account, $edit = array(), $category = 'account') {
     user_module_invoke('update', $edit, $user, $category);
   }
   else {
+    // Allow 'uid' to be set by the caller. There is no danger of writing an
+    // existing user as drupal_write_record will do an INSERT.
+    if (empty($edit['uid'])) {
+      $edit['uid'] = db_next_id(db_query('SELECT MAX(uid) FROM {users}')->fetchField());
+    }
     // Allow 'created' to be set by the caller.
     if (!isset($edit['created'])) {
       $edit['created'] = REQUEST_TIME;