have a database with any number of documents in it. create a map that outputs 0 things (no emits called). use reduce : "_stats". an error should occur.
it's very common to have views be an empty set since maps act as filters in couchdb.
when i use my own reduce functions i don't get errors, only with the standard couchdb functions.
this wouldn't be a problem if i could use commonJS in my reduces.