rails--rails/guides/source/6_0_release_notes.md

**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON https://guides.rubyonrails.org.**

Ruby on Rails 6.0 Release Notes
===============================

Highlights in Rails 6.0:

* Action Mailbox
* Action Text
* Parallel Testing
* Action Cable Testing

These release notes cover only the major changes. To learn about various bug
fixes and changes, please refer to the change logs or check out the [list of
commits](https://github.com/rails/rails/commits/6-0-stable) in the main Rails
repository on GitHub.

--------------------------------------------------------------------------------

Upgrading to Rails 6.0
----------------------

If you're upgrading an existing application, it's a great idea to have good test
coverage before going in. You should also first upgrade to Rails 5.2 in case you
haven't and make sure your application still runs as expected before attempting
an update to Rails 6.0. A list of things to watch out for when upgrading is
available in the
[Upgrading Ruby on Rails](upgrading_ruby_on_rails.html#upgrading-from-rails-5-2-to-rails-6-0)
guide.

Major Features
--------------

### Action Mailbox

[Pull Request](https://github.com/rails/rails/pull/34786)

[Action Mailbox](https://github.com/rails/rails/tree/6-0-stable/actionmailbox) allows you
to route incoming emails to controller-like mailboxes.
You can read more about Action Mailbox in the [Action Mailbox Basics](action_mailbox_basics.html) guide.

### Action Text

[Pull Request](https://github.com/rails/rails/pull/34873)

[Action Text](https://github.com/rails/rails/tree/6-0-stable/actiontext)
brings rich text content and editing to Rails. It includes
the [Trix editor](https://trix-editor.org) that handles everything from formatting
to links to quotes to lists to embedded images and galleries.
The rich text content generated by the Trix editor is saved in its own
RichText model that's associated with any existing Active Record model in the application.
Any embedded images (or other attachments) are automatically stored using
Active Storage and associated with the included RichText model.

You can read more about Action Text in the [Action Text Overview](action_text_overview.html) guide.

### Parallel Testing

[Pull Request](https://github.com/rails/rails/pull/31900)

[Parallel Testing](testing.html#parallel-testing) allows you to parallelize your
test suite. While forking processes is the default method, threading is
supported as well. Running tests in parallel reduces the time it takes
your entire test suite to run.

### Action Cable Testing

[Pull Request](https://github.com/rails/rails/pull/33659)

[Action Cable testing tools](testing.html#testing-action-cable) allow you to test your
Action Cable functionality at any level: connections, channels, broadcasts.

Railties
--------

Please refer to the [Changelog][railties] for detailed changes.

### Removals

### Deprecations

### Notable changes

Action Cable
------------

Please refer to the [Changelog][action-cable] for detailed changes.

### Removals

### Deprecations

### Notable changes

*   The ActionCable javascript package has been converted from CoffeeScript
    to ES2015, and we now publish the source code in the npm distribution.

    This allows ActionCable users to depend on the javascript source code
    rather than the compiled code, which can produce smaller javascript bundles.

    This change includes some breaking changes to optional parts of the
    ActionCable javascript API:

    - Configuration of the WebSocket adapter and logger adapter have been moved
      from properties of `ActionCable` to properties of `ActionCable.adapters`.

    - The `ActionCable.startDebugging()` and `ActionCable.stopDebugging()`
      methods have been removed and replaced with the property
      `ActionCable.logger.enabled`.

Action Pack
-----------

Please refer to the [Changelog][action-pack] for detailed changes.

### Removals

### Deprecations

### Notable changes

Action View
-----------

Please refer to the [Changelog][action-view] for detailed changes.

### Removals

### Deprecations

### Notable changes

Action Mailer
-------------

Please refer to the [Changelog][action-mailer] for detailed changes.

### Removals

### Deprecations

### Notable changes

Active Record
-------------

Please refer to the [Changelog][active-record] for detailed changes.

### Removals

### Deprecations

### Notable changes

Active Storage
--------------

Please refer to the [Changelog][active-storage] for detailed changes.

### Removals

### Deprecations

### Notable changes

Active Model
------------

Please refer to the [Changelog][active-model] for detailed changes.

### Removals

### Deprecations

### Notable changes

Active Support
--------------

Please refer to the [Changelog][active-support] for detailed changes.

### Removals

### Deprecations

### Notable changes

Active Job
----------

Please refer to the [Changelog][active-job] for detailed changes.

### Removals

### Deprecations

### Notable changes

Ruby on Rails Guides
--------------------

Please refer to the [Changelog][guides] for detailed changes.

### Notable changes

Credits
-------

See the
[full list of contributors to Rails](https://contributors.rubyonrails.org/)
for the many people who spent many hours making Rails, the stable and robust
framework it is. Kudos to all of them.

[railties]:       https://github.com/rails/rails/blob/6-0-stable/railties/CHANGELOG.md
[action-pack]:    https://github.com/rails/rails/blob/6-0-stable/actionpack/CHANGELOG.md
[action-view]:    https://github.com/rails/rails/blob/6-0-stable/actionview/CHANGELOG.md
[action-mailer]:  https://github.com/rails/rails/blob/6-0-stable/actionmailer/CHANGELOG.md
[action-cable]:   https://github.com/rails/rails/blob/6-0-stable/actioncable/CHANGELOG.md
[active-record]:  https://github.com/rails/rails/blob/6-0-stable/activerecord/CHANGELOG.md
[active-storage]: https://github.com/rails/rails/blob/6-0-stable/activestorage/CHANGELOG.md
[active-model]:   https://github.com/rails/rails/blob/6-0-stable/activemodel/CHANGELOG.md
[active-support]: https://github.com/rails/rails/blob/6-0-stable/activesupport/CHANGELOG.md
[active-job]:     https://github.com/rails/rails/blob/6-0-stable/activejob/CHANGELOG.md
[guides]:         https://github.com/rails/rails/blob/6-0-stable/guides/CHANGELOG.md