To edit/show encrypted file:

```
bin/rails encrypted:edit config/staging_tokens.yml.enc
bin/rails encrypted:edit config/staging_tokens.yml.enc --key config/staging.key
bin/rails encrypted:show config/staging_tokens.yml.enc
```

Also provides a backing Rails.application.encrypted API for Ruby access:

```ruby
Rails.application.encrypted("config/staging_tokens.yml.enc").read
Rails.application.encrypted("config/staging_tokens.yml.enc").config
Rails.application.encrypted("config/staging_tokens.yml.enc", key: "config/staging.key")
```

Ensure plugin_generator adds to new line in Gemfile, even if the Gemfile
does not end with an empty line.

[Lisa Ugray, Nikita Penzin]

Currently the environment is not loaded in some db tasks.
Therefore, if use encrypted secrets values in `database.yml`,
`read_encrypted_secrets` will not be true, so the value can not be
used correctly.

To fix this, added `environment` as dependency of `load_config`.
It also removes explicit `environment` dependencies that are no longer
needed.

Fixes #30717

Make clear that the files are not to be run for interpreters.

Fixes #23847.
Fixes #30690.
Closes #23878.

Allow edits of existing encrypted secrets generated on Rails 5.1,
but refer to credentials when attempting to setup.

This also removes the need for any of the setup code, so the
generator can be ripped out altogether.

Since credentials generator is executed via the credentials command and
does not need to be executed directly, so it is not necessary to show it in
help.

These were added in #30101, after #31084 it became redundant.

Since isolation application is generated with the `--skip-gemfile`
option, so `active_storage:install` is not executed.

In order to execute the `rails` command, need to run bundle install in
advance.
Therefore, if skipped bundle install, `rails` command may fail and
should not do it.

Ensure that `bin/rails db:migrate` with specified `VERSION` reverts
all migrations only if `VERSION` is `0`.
Raise error if target migration doesn't exist.

Omit `rails activestorage:install` for jdbcmysql, jdbc and shebang tests

AppGeneratorTest#test_config_jdbcmysql_database

  rails aborted!
  LoadError: Could not load 'active_record/connection_adapters/mysql_adapter'.
  Make sure that the adapter in config/database.yml is valid.
  If you use an adapter other than 'mysql2', 'postgresql' or 'sqlite3' add
  the necessary adapter gem to the Gemfile.
  (compressed)
  bin/rails:4:in `<main>'
  Tasks: TOP => activestorage:install => environment
  (See full trace by running task with --trace)

AppGeneratorTest#test_config_jdbc_database

  rails aborted!
  LoadError: Could not load 'active_record/connection_adapters/jdbc_adapter'.
  Make sure that the adapter in config/database.yml is valid.
  If you use an adapter other than 'mysql2', 'postgresql' or 'sqlite3' add
  the necessary adapter gem to the Gemfile.
  (compressed)
  bin/rails:4:in `<main>'
  Tasks: TOP => activestorage:install => environment
  (See full trace by running task with --trace)

AppGeneratorTest#test_shebang_is_added_to_rails_file

  /home/ubuntu/.rbenv/versions/2.4.1/bin/ruby: no Ruby script found in input (LoadError)

Prevent PendingMigrationError in tests

 * Run `bin/rails db:migrate RAILS_ENV=test` in test_cases before start tests to prevent PendingMigrationError
 * FileUtils.rm_r("db/migrate")
 * --skip-active-storage

Fix failed tests in `railties/test/railties/engine_test.rb`

Related to #30111

Imporve `SharedGeneratorTests#test_default_frameworks_are_required_when_others_are_removed`

 - Explicitly skip active_storage
 - Ensure that skipped frameworks are commented
 - Ensure that default frameworks are not commented

Fix error `Errno::ENOSPC: No space left on device - sendfile`

Since `rails new` runs `rails active_storage:install`
that boots an app.

Since adding Bootsnap 0312a5c6
during booting an app, it creates the cache:

   264K    tmp/cache/bootsnap-load-path-cache
   27M     tmp/cache/bootsnap-compile-cache

* teardown_app must remove app

Closes #30102

Revert part 787fe90d

--skip-active-storage pass throughs `rails plugin new`

Add changelog entry about default initialization of Active Storage

Currently, namespaced scaffold generator will generate an incorrect path
and the generated file will not work properly.

```
$ ./bin/rails g scaffold admin/user
$ ./bin/rails db:migrate
$  ./bin/rails t test/controllers
# Running:

E

Error:
Admin::UsersControllerTest#test_should_create_admin_user:
NameError: undefined local variable or method `admin_admin_users_url' for #<Admin::UsersControllerTest:0x000055a59f25ff68>
Did you mean?  admin_users
    test/controllers/admin/users_controller_test.rb:20:in `block (2 levels) in <class:UsersControllerTest>'
    test/controllers/admin/users_controller_test.rb:19:in `block in <class:UsersControllerTest>'

bin/rails test test/controllers/admin/users_controller_test.rb:18
```

This is because combine `controller_class_path` and `singular_table_name`
to generate route.
https://github.com/rails/rails/blob/360698aa245b45349d1d1b12e1afb34759515e69/railties/lib/rails/generators/named_base.rb#L172

Normally, if using namspaced generator, table name already contains
namespace. Therefore, adding `controller_class_path` adds extra namespace.
Since it is special only when explicitly specifying `model-name`, it is
modified to change the value only when `model-name`is specified.

Follow up of #30729

`routes` task always returns zero to status, so status is not to non-zeno.
Ref: https://github.com/rails/rails/blob/b1867c480dd5476948ff0492ea2f91e2c2fcb04b/railties/lib/rails/tasks/routes.rake#L30

Ref: https://github.com/rails/rails/blob/3be123ba26cad461a80d7d680819e71c1388a241/railties/test/isolation/abstract_unit.rb#L243

  When load schema from `structure.sql`, database connection isn't
  established. `ActiveRecord::Tasks::DatabaseTasks.load_schema` has to
  establish database connection since it executes
  ```
  ActiveRecord::InternalMetadata.create_table
  ActiveRecord::InternalMetadata[:environment] = environment
  ```

Fix `bin/rails db:setup` and `bin/rails db:test:prepare` create  wrong ar_internal_metadata's data for a test database.

  Before:
  ```
  $ RAILS_ENV=test rails dbconsole
  > SELECT * FROM ar_internal_metadata;
  key|value|created_at|updated_at
  environment|development|2017-09-11 23:14:10.815679|2017-09-11 23:14:10.815679
  ```

  After:
  ```
  $ RAILS_ENV=test rails dbconsole
  > SELECT * FROM ar_internal_metadata;
  key|value|created_at|updated_at
  environment|test|2017-09-11 23:14:10.815679|2017-09-11 23:14:10.815679
  ```

  Fixes #26731.

In this test file, "server option" refers to the server used to start
Rails(e.g. `puma`, `thin`).
But this test, "server option" is not specified. Therefore, I think that
it is incorrect that `server_option` is included in the test name.

Added test case for starting rails with daemon option, this should set the option[:daemonize] to true, otherwise the option[:daemonize] will be set to false

Ruby 2.5 warns about this. Ref: https://travis-ci.org/rails/rails/jobs/286338999

  - Remove redundant setting `RAILS_ENV` for `db:test:prepare`.
    `db:test:prepare` doesn't require it.

See #30520

If need a parse result of arguments, can obtain it by creating
an instance of the command.

The `abstract_unit` loads `rails/all`. Therefore, `Rails` is definitely defined.
Also, since `Info` is autoloaded, do not need to explicitly load the file.
https://github.com/rails/rails/blob/3ede539357acc91e377611cea9dd5f30678e7b2a/railties/lib/rails.rb#L29

When puma/puma#1403 is merged Puma will support the Early Hints status
code for sending assets before a request has finished.

While the Early Hints spec is still in draft, this PR prepares Rails to
allowing this status code.

If the proxy server supports Early Hints, it will send H2 pushes to the
client.

This PR adds a method for setting Early Hints Link headers via Rails,
and also automatically sends Early Hints if supported from the
`stylesheet_link_tag` and the `javascript_include_tag`.

Once puma supports Early Hints the `--early-hints` argument can be
passed to the server to enable this or set in the puma config with
`early_hints(true)`. Note that for Early Hints to work
in the browser the requirements are 1) a proxy that can handle H2,
and 2) HTTPS.

To start the server with Early Hints enabled pass `--early-hints` to
`rails s`.

This has been verified to work with h2o, Puma, and Rails with Chrome.

The commit adds a new option to the rails server to enable early hints
for Puma.

Early Hints spec:
https://tools.ietf.org/html/draft-ietf-httpbis-early-hints-04

[Eileen M. Uchitelle, Aaron Patterson]

In Rails engine, migration files are in under `db/migrate` of engine.
Therefore, when rake task is executed in engine, `db/migrate` is
automatically added to `DatabaseTasks.migrations_paths`.
https://github.com/rails/rails/blob/a18cf23a9cbcbeed61e8049442640c7153e0a8fb/activerecord/lib/active_record/railtie.rb#L39..L43

However, if execute the rake task under dummy app, migration files will not
be loaded because engine's migration path setting process is not called.

Therefore, in order to load migration files correctly, it is necessary to
execute rake task under engine.

Fixes #30765

Because dummy application is only for use test, so credentials is
unnecessary.

Since warning was issued due to duplication of test names, fix the test
name to a meaningful name.

This fixes following warnings:

```
railties/test/generators/named_base_test.rb:141: warning: method redefined; discarding old test_scaffold_plural_names
railties/test/generators/named_base_test.rb:62: warning: previous definition of test_scaffold_plural_names was here
```

See the changelog entry.

Remove `secrets.secret_token` from the bug report templates,
since we don't accept bug reports for Rails versions that
don't support a `secret_key_base`.

[ claudiob & Kasper Timm Hansen ]

`about_yml_plugins` is no longer used since 82b9b151

Based on, yet closes https://github.com/rails/rails/pull/30708

Fix the session test by properly truncating the legacy encryption
key for cbc encryption. Borrowed straight from 👆.

Fix the cookies test a little differently than the PR. Basically
keep every config within the config block.

[ Michael Coyne & Kasper Timm Hansen ]

If specify the `quiet` option, expect that no status will be shown.
However, some process show status. This suppresses all status output.

Both classes now have a rotate method where new instances are added for
each call. When decryption or verification fails the next rotation
instance is tried.

Binding to capture the local scope. This means that if a constant with same
name as constant specified by the user exists in local scope, constant
defined in local will use. This is different from what the user expects.
Therefore, fixed to use top-level binding instead of local scope.

Fixes #30644