Mountable engine routes

[Adrxx]

Im trying to create a a mountable engine with devise on it, I've followed this tutorial: https://github.com/plataformatec/devise/wiki/How-To:-Use-devise-inside-a-mountable-engine
And everything works fine, except the routes. My engine is mounted in the route admin like this:

 mount C4::Engine => "/admin"

but when devise redirects the user (like when it hasn't signed in) it redirects to a path without the '/admin' prefix and gives me the usual No route matches [GET] /users/sign_in because the correct route is admin/users/sign_in.

I'm kind of new to rails mountable engines so It could be just me, is this a devise issue?

[Adrxx]

Ok, It seems I wasn't using the correct devise version, devise 3.5.1 works fine.

[patricklindsay]

I think this should be reopened (?)

I am having the same problem using 3.5.6, downgrading to 3.5.1 fixes the problem however opens my app up to security issues

[patricklindsay]

Dup issue: #3705