A while ago I discussed with @tenderlove - we currently use \n characters to separate multiple headers. e.g.

{"set-cookie" => "foo=x\nbar=y"}

Internally HeaderHash uses an Array I believe, e.g. something like:

{"set-cookie" => ["foo=x", "bar=y"]}

Personally I like this formulation better, it's more efficient for the server implementation and it's easier from the user POV to deal with too. It seems like less of a hack, and it should minimise

So, I vote to deprecate/remove the "\n" representation and prefer the Array representation.

The only limitation is going to be if people start using it everywhere, e.g..

{"content-type" => ["text/html"]}

There are different solutions to this problem: e.g., we could define only certain headers can work like this (notably set-cookie would make sense) or we could mark certain headers as NOT being allowed to be an array (e.g. content-length).

(Epic #1593)