call `serve` with the request on dispatchers
dispatcher doesn't need `call` anymore
move path_parameter encoding check to the request object
rm reset_parameters because we automatically do it from 9ca4839a
Merge branch 'constraints'

* constraints:
  rm reset_parameters because we automatically do it from 9ca4839a
  move path_parameter encoding check to the request object
  dispatcher doesn't need `call` anymore
  call `serve` with the request on dispatchers
  constraints class does not need the request class anymore
  give all endpoints a superclass
  skip the build business if the stack is empty
  stop hardcoding path_parameters and get it from the request
  we do not need to cache rack_app
  a redirect is not a dispatcher by definition, so eliminate test
  push is_a check up to where the Constraints object is allocated
  pass the request object to the application
  pass a request to `matches?` so we can avoid creating excess requests
  nothing is passed to `rack_app` anymore, so rm the params
  one fewer is_a check
  Constraints#app should never return another Constraints object, so switch to if statement
  eliminate dispatcher is_a checks
  push is_a?(Dispatcher) check in to one place
  Always construct route objects with Constraint objects

Conflicts:
	actionpack/lib/action_controller/metal.rb
PARAMETERS_KEY is only used in the request, so move the constant there
rm dead code
Add test case for clear mappings
Deprecate all *_filter callbacks in favor of *_action callbacks

This is the continuation of the work started at
9d62e04838f01f5589fa50b0baa480d60c815e2c
Merge pull request #15373 from akshay-vishnoi/test-cases

Add test case for clear mappings
Merge pull request #15269 from arunagw/aa-fixes-8930

rake railties:install:migrations respects the order of railties
Add CHANGELOG entry for #15269 [ci skip]
Remove AR Properties from the public API

Making this part of the public API was premature, let's make it private
again while I continue to work on the surrounding code.
Merge pull request #15374 from sgrif/sg-private-properties

Remove AR Properties from the public API
Move types to the top level `ActiveRecord` namespace

`ActiveRecord::ConnectionAdapters::Type::Value` =>
`ActiveRecord::Type::Value`
pg, keep `hstore` and `json` attributes as `Hash` in @attributes.

The solution presented in this patch is not efficient. We should replace it
in the near future. The following needs to be worked out:
  * Is `@attributes` storing the Ruby or SQL representation?
  * `cacheable_column?` is broken but `hstore` and `json` rely on that behavior

Refs #15369.

/cc @sgrif @rafaelfranca
Initial doc for TransactionIsolationError [ci skip]
Add with_default_charset helper.
Merge pull request #15381 from zuhao/refactor_actionpack_content_type_test

Add with_default_charset helper.
Move I18n.locale setting into setup and teardown.