The implementation of HashWithIndifferentAccess#default didn't
distinguish `default` from `default(nil)`, which caused an incorrect
result for `default` if `nil` was used as a key.

Define HashWithIndifferentAccess#dig so that hackery that behaves
differently from Hash#default can be removed from
HashWithIndifferentAccess#default.

Extract `FakeKlass` in `relation_test.rb` and `relation/mutation_test.rb`

Enable Layout/EmptyLineAfterMagicComment cop

Fix english for the rescue_from warning [ci skip]

Fix PostgreSql adapter setup for ActionCable tests

(cherry picked from commit e2093c1f678175bde7c37c848686d979427346e1)
(cherry picked from commit d7dbe48273bd9e0adb1de5b52e3cdaeb4a65630b)

`FakeKlass` in `relation_test.rb` and `relation/mutation_test.rb` are
almost the same.

Fix typo in method name

[ci skip]

Default protect from forgery

Since we now default to `protect_from_forgery with: :exception`,
provide a wrapper to `skip_before_action :verify_authenticity_token`
for disabling forgery protection.

Rather than protecting from forgery in the generated
ApplicationController, add it to ActionController::Base by config. This
configuration defaults to false to support older versions which have
removed it from their ApplicationController, but is set to true for
Rails 5.2.

Don't eagerly require Rails' minitest plugin.

By making the Rails minitest behave like a standard minitest plugin
we're much more likely to not break when people use other minitest
plugins. Like minitest-focus and pride.

To do this, we need to behave like minitest: require files up front
and then perform the plugin behavior via the at_exit hook.
This also saves us a fair bit of wrangling with test file loading.

Finally, since the environment and warnings options have to be applied
as early as possible, and since minitest loads plugins at_exit, they
have to be moved to the test command.

* Don't expect the root method.

It's likely this worked because we eagerly loaded the Rails minitest plugin
and that somehow defined a root method on `Rails`.

* Assign a backtrace to failed exceptions.

Otherwise Minitest pukes when attempting to filter the backtrace (which
Rails' backtrace cleaner then removes).

Means the exception message test has to be revised too.

This is likely caused by the rails minitest plugin now being loaded for
these tests and assigning a default backtrace cleaner.

Make sidekiq and resque integration tests work in CI

Since f55ecc6a, the integration test of sidekiq and resque is not working
in CI.
https://travis-ci.org/rails/rails/jobs/251783876

Because f55ecc6a required a password to access redis.
Therefore, handling by passing passwords when connecting to redis.

Use frozen-string-literal in ActiveJob

[ci skip] Updated language on validations.

Update MessageEncryptor example to use dynamic key length

Treat secrets as binary

Load environment file in `dbconsole` command

Prepare AP and AR to be frozen string friendly

Use frozen-string-literal in ActiveSupport

Currently the environment file is not loaded in `dbconsole` command.
Therefore, for example, if use encrypted secrets values in database.yml,
`read_encrypted_secrets` will not be true, so the value can not be
used correctly.

Fixes #29717

Until Rails 5.1.1 secrets was treated as binary inside Rails.
https://github.com/rails/rails/blob/v5.1.1/railties/lib/rails/secrets.rb#L59
https://github.com/rails/rails/blob/v5.1.1/railties/lib/rails/secrets.rb#L63

However, it is treated as String in Rails 5.1.2(changed by 157db872).
https://github.com/rails/rails/blob/v5.1.2/railties/lib/rails/secrets.rb#L104
https://github.com/rails/rails/blob/v5.1.2/railties/lib/rails/secrets.rb#L108

As a result, when upgrading from Rails 5.1.1 to 5.1.2, to write the value
treated as binary using `File.write`, causing an error.

In order to avoid `UndefinedConversionError`, fixed it to treat it as
binary like 5.1.1.
Fixes #29696

Don't allow uuids with orphan curly braces