this is so we can show route output in the development when we get a routing error. Railties can use features of ActionDispatch, but ActionDispatch should not depend on Railties.

If someone receives a routing error, they likely need to view the routes. Rather than making them visit '/rails/info/routes' or run `rake routes` we can give them that information on the page.

Assuming the type ":touch", Collector.new was calling
send(:touch), which instead of triggering method_missing
and generating a new collector method, actually
invoked the private method `touch` inherited from
Object.

By generating the method for each mime type as it
is registered, the private methods on Object can
never be reached by `send`, because the `Collector`
will have them before `send` is called on it.

To do this, a callback mechanism was added to Mime::Type

This allows someone to add a callback for whenever
a new mime type is registered. The callback then
gets called with the new mime as a parameter.

This is then used in AbstractController::Collector
to generate new collector methods after each mime
is registered.

This reverts commit 9669f6f7.

This breaks Sam Ruby's tests for some reason.  Revert until we figure it
out.

Signed-off-by: NFrançois de Metz <francois@stormz.me>

instead of deleting keys on every instantiation, create defaults we
actually use.  eventually we can pass an environment in to the request,
and create a new req / res object on each call.

merging cookies is responsibility of the test runner

For some reason, this special logic is only supposed to be executed on
the second request.  For now, we'll extend on recycle, but we should
figure out why this functionality can't be run on every request

Try to avoid making the controller mutate itself so that we can
eventually make the response async

Also fix some wrong formatting.

Related discussion:
https://github.com/rails/rails/commit/ab72040b74f742b6676b2d2a5dd029bfdca25a7a#commitcomment-1525256

ActiveModel is used in ActionPack for ActiveModel::Naming for a few,
mostly optional aspects of ActionPack related to automatically converting
an ActiveModel compliant object into a key for params and routing. It uses
only three methods of ActiveModel (ActiveModel::Naming.route_key,
ActiveModel::Naming.singular_route_key and ActiveModel::Naming.param_key).

Related with 5e7d6bba

This reverts commit 6acebb38.

Usage of this feature did not reveal any improvement in existing apps.

Conflicts:

	actionpack/lib/action_dispatch/routing/mapper.rb
	guides/source/routing.textile
	railties/lib/rails/engine.rb
	railties/lib/rails/paths.rb
	railties/test/paths_test.rb

remove AV.prepare and move all helper-related logic into the controller. this decouples the view since it no longer knows about routes internals.
this is a result of an ongoing discussion at https://github.com/rails/rails/pull/6826.

Deprecate usage of filter object with #before and #after
methods as around callback

the method has gone in this commit: 119e9e2d

They also make more sense here since all the related logic with I18n is
handled by AS::NumberHelper, and not by AV anymore.

Just make use of the returning exception from assert_raise, instead of
calling the method again with a rescue clause to test the saved
exception number.

ActiveSupport::NumberHelper does not make use of :raise, so there's no
need to propagate it down.