Onf of the sides can be nil and it will raise a Conversion error

In some instances, `assert_redirected_to` assertion was returning an
incorrect and misleading failure message when the assertion failed.
This was due to a disconnect in how the assertion computes the redirect
string for the failure message and how `redirect_to` computes the
string that is actually used for redirection.

I made the `_compute_redirect_to_loaction` method used by `redirect_to`
public and call that from the method `assert_redirect_to` uses to
calculate the URL.

The reveals a new test failure due to the regex used by
`_compute_redirect_to_location` allow `_` in the URL scheme.

This reverts commit ab5cd54b, reversing
changes made to cdc10c89.

Reason: This way of defining root path is still supported. See
https://github.com/rails/rails/blob/d262773ab7f0aae5de2d354ac2eca168e95b653d/actionpack/test/controller/routing_test.rb#L450-457

Reference:
Bloody mess internals
http://gusiev.com/slides/rails_contribution/static/#40

The documentation in this section is referring to a profile,
so the resource that's created should probably also be a
profile of some sort.

The docs refference a blacklist, but really what's being described
is a whitelist. Anything that matches the constraint gets through to
the path.

This piece of documentation is out of date.
The use of match without any via option is prevented, now
the HTTP verbs have to be explicitly set. If they're not set then
the error message in normalize_conditions! (around line 186) is
shown.

Refactor of the work done in #11891

This reverts commit 70d6e16f, reversing
changes made to ea4db3bc.

Seems to be a code merge done by mistake.

update Rails::Railtie::Configuration and ActionDispatch::Response#respond_to? to accept include_private argument

Normalize file parameters in same place as other parameters (ActionDispatch::Http::Parameters#normalize_encode_params)

#assert_dom_equal and #assert_dom_not_equal both take a "failure"
message argument, but this argument was not utilized.

Reference:
Bloody mess internals
http://gusiev.com/slides/rails_contribution/static/#40

Allow REMOTE_ADDR, HTTP_HOST and HTTP_USER_AGENT to be overridden from
the environment passed into `ActionDispatch::TestRequest.new`.

Fixes #11590

Fix an issue where Journey was failing to clear the named routes hash when the
routes were reloaded and since it doesn't overwrite existing routes then if a
route changed but wasn't renamed it kept the old definition. This was being
masked by the optimised url helpers so it only became apparent when passing an
options hash to the url helper.

Only build the missing_keys array once we have detected that there
actually are missing keys by moving the check to be part of the block
that performs the path substitution.

When optimized path helpers were re-introduced in d7014bc7 the test added
in a328f2ff broke but no-one noticed because it wasn't being run by the
test suite.

Fix the test by checking for nil values or empty strings after the args
have been parameterized.

When generating an unnamed url (i.e. using `url_for` with an options
hash) we should skip anything other than standard Rails routes otherwise
it will match the first mounted application or redirect and generate a
url with query parameters rather than raising an error if the options
hash doesn't match any defined routes.

Fixes #8018

In order to get raw_post to be not empty after
ParamsParser#parse_formatted_parameters,
added rewinding of body stream input on parsing json params.

Closes #11345

Set ActionDispatch.test_app instead.

request thread to return up the stack before the instance variable is
assigned.  Synchronize so that the ivar is assigned before the other
thread can activate.

fixes #10984

Merge `:action` from routing scope and assign endpoint if both `:controller`
and `:action` are present. The endpoint assignment only occurs if there is
no `:to` present in the options hash so should only affect routes using the
shorthand syntax (i.e. endpoint is inferred from the the path).

Fixes #9856