Major - P3 The renameCollection command will incorrectly roll back the collection drop when renaming a collection across databases with the {dropTarget: true} option. The command will fail with the error message "collection already exists" when this happens. Affects 2.7.8.
To reproduce:
> use test switched to db test > db.foo.drop() true > db.foo.insert({}) WriteResult({ "nInserted" : 1 }) > db.getSiblingDB("test2").bar.drop() false > db.getSiblingDB("test2").bar.insert({}) WriteResult({ "nInserted" : 1 }) > db.adminCommand({renameCollection:"test.foo",to:"test2.bar",dropTarget:true}) { "errmsg" : "exception: collection already exists", "code" : 17399, "ok" : 0 }