Design documents seem to accept invalid views.
Going by the documentation for design documents: http://docs.couchdb.org/en/latest/api/ddoc/common.html#put--db-_design-ddoc , a view should be an object that has a map (a string) and an optional reduce (string).
Interestingly some validation is performed to check that views field itself is an object. For example:
Also there is a deeper level validation of map functions:
If there is interest, I have a patch that, if provided: views, filters, lists, show, updates, options are objects. rewrites are arrays, validate_doc_update and language are strings.
Then if views is provided, each view is an object. It must have a map function (a string) and an optional reduce function (also a string).
Here is an example how it works: