Question

Is there a way to disable the ERB handler in Rails.

This may sound silly but we’re migrating to SLIM and want to
prevent that some lazy developers still use ERB.

Answer 1

As far as I can see there’s no way to unregister a template handler.

But we can do it by means of a hack.

the ActionView::Template::Handlers::ERB has the following line;

self.class.erb_implementation.new(
  erb,
  :trim => (self.class.erb_trim_mode == "-")
).src

So lets break it, for fun.

We’ll add an initializer config/initializers/no_erb_allowed.rb

class NoErbAllowed
  def initialize(*args)
    raise "ERB is not allowed"
  end
end

ActionView::Template::Handlers::ERB.erb_implementation = NoErbAllowed

Any view that tries to use ERB will then raise the error

ActionView::Template::Error (ERB is not allowed):