1 files changed, 25 insertions, 0 deletions
diff --git a/lib/puppet/util/rails/collection_merger.rb b/lib/puppet/util/rails/collection_merger.rb
new file mode 100644
index 000000000..7afd76f9c
--- /dev/null
+++ b/lib/puppet/util/rails/collection_merger.rb
@@ -0,0 +1,25 @@
+module Puppet::Util::CollectionMerger
+    # Merge new values with the old list.  This is only necessary
+    # because deletion seems to mess things up on unsaved objects.
+    def collection_merge(collection, list)
+        remove = send(collection).dup
+
+        list.each do |value|
+            object = yield(value)
+            if remove.include?(object)
+                remove.delete(object)
+            end
+        end
+
+        unless remove.empty?
+            # We have to save the current state else the deletion somehow deletes
+            # our new values.
+            save
+            remove.each do |r|
+                send(collection).delete(r)
+            end
+        end
+    end
+end
+
+# $Id$