When using Collection.rename original object is modified by 'self.collectionName = newName' and it breaks other rename operations. When you try to execute rename() on the same object twice it will try to do:

1. A.rename('B'); <--- it renames 'A' to 'B'
2. A.rename('B'); <--- it renames 'B' to 'B' because collectionName property of object was modified.

It took me few hours to fix this behavior by setting

option as parameter. It should be set by default as posted here: https://jira.mongodb.org/browse/CASBAH-22

"To clarify: rename should NOT mutate the collection, but return a new collection instance pointing at the new name."

Broken source (line 108): https://github.com/mongodb/node-mongodb-native/blob/master/lib%2Fmongodb%2Fcollection%2Fcommands.js#L108