* Add binary encoding logic into ActionDispatch::Request::Utils

Moving the logic to set binary encoding into ActionDispatch::Request::Utils
will allow us to encode from GET and POST in ActionDispatch::Request.

* Refactor binary encoding logic

- Move binary encoding calls into GET, POST and path_parameters
- Remove binary encoding from ActionDispatch::Http::Request
- This way, we only raise an invalid encoding exception if the controller is not requesting
parameters in binary encoding

* Check if encoding is valid in ActionDispatch::Request#POST and raise BadRequest if invalid

* Fix multipart_params_test that has binary-encoded params containing invalid UTF-8 characters

* Address PR comments

* Pass action and controller to Request::Utils.set_binary_encoding

[Rafael Mendonça França + Adrianna Chang]

https://github.com/rails/rails/commit/895134bcff294b05d6f6ebb101f60e3083ec5461#diff-7789e18ec0a61c6845755a257e6eb34fR3
https://github.com/rails/rails/commit/ee9e308f686ac1c7b0714671a1dcf1d96de87d70#diff-5e9551294914b338d923032fa904c6beR103
https://github.com/rails/rails/commit/5f63c771f7ce751fefd000470bf4ccab421988d7#diff-600d5368b55e46ed961abb4295977ac3R506
https://github.com/rails/rails/commit/48b6bacbc534d4be3fa89bc19ea83c357a20e598#diff-279ac5c088a3ee7e9f954bbc10d1b773R246
https://github.com/rails/rails/commit/49adb7f4c61de8cbb02c4a207dbd56093d99e795#diff-0cbe7171fdd7821fd5836896849141c0R111
https://github.com/rails/rails/commit/9bfe89e68ee61d9c8ed71ac98c783a7e47bdb608#diff-9c1c95b001e3680ba8a473cf23508b68R8
https://github.com/rails/rails/commit/a0f18e60900fc45eb3524ab3cdfe57be430d6016#diff-bef0ae2c16dacf77bfd2ba099af8a330R47
https://github.com/rails/rails/commit/8b4d344815655027d9f7584c0a59271dce8f1d5a#diff-09660f59aee7ec893ad609315e8843c5R18
https://github.com/rails/rails/commit/49d1b5a98dc50ca59bbfb817f90eb5c2c2645d30#diff-531e71a9d5fdc8181f38ce4416553694R107
https://github.com/rails/rails/commit/b674f04756e2e23fc18308319e4de8ff562575f4#diff-7521c0bb452244663b689e77658e63e3R98
https://github.com/rails/rails/commit/a9012af6883284a35bc5e6166507d429fe10482d#diff-60bdcf1e1954ec56d41fc4c7bd8d3e39R512
https://github.com/rails/rails/commit/6380aee182a6acb4f5062c5aa377d290e696e4b7#diff-5158c234d5e19bb1cffadcbc088400f1R262
https://github.com/rails/rails/commit/c7820d8124c854760a4d288334f185de2fb99446#diff-f4614e7ba8081c0c9e20fe64b6374228R60
https://github.com/rails/rails/commit/8df7ed3b88fc9f19446d7207a745a331893b81cd#diff-0495ed68f82d1bbde593ab5491eab24aR169
https://github.com/rails/rails/commit/6f94260ac67755fbc4d89e7dd9ba6be04abfa9e7#diff-7ecb6672f3fd37dfb79c4539395d3857R28
https://github.com/rails/rails/commit/03e44f93001db97953917e0a100c627e189e2be6#diff-e9234c4c6668852448059c0a35840bcaR185

Calling self in an action of a controller generates an endless stream of
characters, including the request object and all instances variables.
This can be frustrating when using a debugger in a controller and
accidentally calling `self` generates output for a couple of seconds.

This shortens inspect to only show the class name.

    MyController.new.inspect # => "#<MyController:0x00000000005028>"

Calling request in an action of a controller generates an endless stream of
characters, including the Rack app and middlewares.
This can be frustrating when using a debugger in a controller and
accidentally calling `request` generates output for a couple of seconds.

Inspect on ActionDispatch::Request is shortened to the most relevant
attributes and uses the same format as used for request in the logs:

    "#<ActionDispatch::Request POST "https://example.com/path/of/some/uri?q=1" for 1.2.3.4>"

Add documentation of Proc usage for SameSite property to configuring.md

Address PR comments
Co-authored-by: NAdrianna Chang <adrianna.chang@shopify.com>

Allow `assert_recognizes` routing assertions to work on mounted root routes.

`Pattern#from_sting` was introduced in bb207ea7 to support creating
patterns from strings in tests (removing a conditional in the initialize
method that had been there only for the sake of those tests).

`Pattern#build` was introduced in 947ebe9a, and was similarly used only
in tests.

My understanding is that [`Mapping#path`][path] is the only place where
we initialize a `Path::Pattern` in library code.

Since these two methods appear to be used only in tests, this
commit moves them out of the class and into a test helper.

My reasoning for doing this is that I am doing some performance work
that may involve a modification to how `Path::Pattern`s get initialized,
and I will have more confidence in that work if I know for sure that
these methods are test helpers that can be modified freely.

[path]: https://github.com/rails/rails/blob/master/actionpack/lib/action_dispatch/routing/mapper.rb#L192-L194

If request format is JSON, keys are converted to Strings, so we have to convert them to Symbols.

This would have made the correct implementation for
894ed87a more obvious.

Co-authored-by: NEugene Kenny <elkenny@gmail.com>

This change ensures we're no longer using a singleton for routes because
we want to change the routing table based on the controller we're
testing. We don't want the routing table to be global for the Action
Pack tests.
Co-authored-by: NAaron Patterson <tenderlove@ruby-lang.org>

308 status code introduced in https://tools.ietf.org/html/rfc7538
preserves the request method unlike 301 status code which would convert
POST requests to GET.

The controller test case is trying to encode json parameters in the same
way it encodes query parameters. However we need to encode json
parameters as json.

This was broken in #39534 because `generate_extras` is encoding
everything into query parameters. But json parameters are in the post
body and need to be treated differently than the query parameters.

Followup to #39651

Aaron Patterson <tenderlove@ruby-lang.org>

[CVE-2020-8185]

- In #39534, `Routing::RouteSet#generate_extras` (which get called)
  by ActionController::TestCase now go through `path_for` which strips
  out all key in the options hash that have the same name as the ones
  defined in `RESERVED_OPTIONS`.

Follow up to c07dff72.

Actually it is not the cop's fault, but we mistakenly use `^`, `$`, and
`\Z` in much places, the cop doesn't correct those conservatively.

I've checked all those usage and replaced all safe ones.

This allows applications to safely upgrade to Rails 6.1 without
breaking tokens while the deploy is still being rolled out.

Prior to this commit, when multiple cookie domains were specified, the
first domain that was a substring of the request host was chosen.  This
allowed, for example, the "example.com" domain to be chosen when the
request host was "example.com.au" or even "myexample.com".

This commit ensures a domain is chosen only if it is equal to or is a
superdomain of the request host.

Fixes #37760.

This PR converts the route params array into an object and moves the
error generation code into its own object as well. This is a refactoring
of internal code to make it easier to change and simplier for internals
to interface with. We have two new objects:

1) `RouteWithParams`

Previously `#generate` returned an array of parameterized parts for a
route. We have now turned this into an object with a `path` and a
`params methods` to be able to access the parts we need.

2) `MissingRoute`

`#generate` was also responsible for constructing the message for the
error. We've moved this code into the new `MissingRoute` object so it
does that work instead.

This change makes these methods reusable throughout the code and easier
for future refactoring we plan to do.
Co-authored-by: NAaron Patterson <aaron.patterson@gmail.com>

When using an external build process (webpack, grunt) it's helpful for
rails to be able to serve those assets. Brotli has better compression
than gzip and should eventually replace it for static assets.

When using an external build process (webpack, grunt) it's helpful for
rails to be able to serve those assets. Brotli has better compression
than gzip and will eventually replace it for static assets.

Move the # outside the < > just like regular Object#inspect

Update rubocop-performance gem and enable Performance/DeletePrefix and Performance/DeleteSuffix cops

The current suggestions are shown on a single line.
Instead we can use some prettier formatting.

The status is defined in RFC 8297 https://tools.ietf.org/html/rfc8297

Fixes offense:

```
actionpack/test/journey/router_test.rb:493:37: C: Style/HashSyntax: Use the new Ruby 1.9 hash syntax.
            options = options.merge(:_recall => recall)
                                    ^^^^^^^^^^^
```

Journey is considered internal, and I would like to stop testing
internals so that we are free to refactor.  This commit just moves us up
one more call frame with the goal if getting closer to a public API.
Once we're up the stack high enough that we're testing a public API we
can stop

Journey is a private API that we want to refactor. We need to stop
calling methods directly on it so we're free to change the
implmentation.

If a parameter isn't found we can suggest similar params:

```
class BooksController < ActionController::Base
  def create
    params.require(:book).require(:name)
    head :ok
  end
end

post :create, params: { magazine: { name: "Mjallo!" } }

param is missing or the value is empty: book
Did you mean?  controller
               action
               magazine

post :create, params: { book: { title: "Mjallo!" } }

param is missing or the value is empty: name
Did you mean?  title

```

* Update `fixture_file_upload` documentation to reflect recent changes. [ci skip]

* Friendlier deprecation message for `fixture_file_upload`.

Suggested change now can be copied and pasted into the code without modification.

If an action isn't found on a controller we can suggest similar actions:

```
The action 'indx' could not be found for SimpleController
Did you mean?  index
```

This makes it safe to replace `reject { |k, v| v.nil? }` with `compact`,
even when the receiver is an `ActionController::Parameters`.