bug in routes scope?

I couldn't find any change to scope in the release notes or changelog but this stopped working since Rails 3:

scope format: false do
     get "main/index"
end

This works though:

get "main/index", format: false

In the first case, using Rails 4 beta 1, getting /main/index.html will work while in the second it won't, as expected.

Should I create an issue on GH for this?

I am pretty sure that there was a change involving this, specifically. It was either Andrew or Yves that made it.

You mean as intentional change/behavior?