Ruby on Rails 6.1 Release Notes

1 Upgrading to Rails 6.1

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 6.0 in case you haven't and make sure your application still runs as expected before attempting an update to Rails 6.1. A list of things to watch out for when upgrading is available in the Upgrading Ruby on Rails guide.

2 Major Features

2.1 Per-database Connection Switching

Rails 6.1 provides you with the ability to switch connections per-database. In 6.0 if you switched to the reading role then all database connections also switched to the reading role. Now in 6.1 if you set legacy_connection_handling to false in your configuration, Rails will allow you to switch connections for a single database by calling connected_to on the corresponding abstract class.

2.2 Horizontal Sharding

Rails 6.0 provided the ability to functionally partition (multiple partitions, different schemas) your database but wasn't able to support horizontal sharding (same schema, multiple partitions). Rails wasn't able to support horizontal sharding because models in Active Record could only have one connection per-role per-class. This is now fixed and horizontal sharding with Rails is available.

2.3 Strict Loading Associations

Strict loading associations allows you to ensure that all your associations are loaded eagerly and stop N+1's before they happen.

2.4 Delegated Types

Delegated Types is an alternative to single-table inheritance. This is helpful for representing class hierarchies allowing the superclass to be a concrete class that is represented by its own table. Each subclass has its own table for additional attributes.

2.5 Destroy Associations Async

Destroy associations async adds the ability for applications to destroy associations in a background job. This can help you avoid timeouts and other performance issues in your application when destroying data.

3 Railties

Please refer to the Changelog for detailed changes.

3.1 Removals

Remove deprecated rake notes tasks.
Remove deprecated connection option in the rails dbconsole command.
Remove deprecated SOURCE_ANNOTATION_DIRECTORIES environment variable support from rails notes.
Remove deprecated server argument from the rails server command.
Remove deprecated support for using the HOST environment variable to specify the server IP.
Remove deprecated rake dev:cache tasks.
Remove deprecated rake routes tasks.
Remove deprecated rake initializers tasks.

3.2 Deprecations

3.3 Notable changes

4 Action Cable

Please refer to the Changelog for detailed changes.

4.1 Removals

4.2 Deprecations

4.3 Notable changes

5 Action Pack

Please refer to the Changelog for detailed changes.

5.1 Removals

Remove deprecated ActionDispatch::Http::ParameterFilter.
Remove deprecated force_ssl at the controller level.

5.2 Deprecations

Deprecate config.action_dispatch.return_only_media_type_on_content_type.

5.3 Notable changes

Change ActionDispatch::Response#content_type to return the full Content-Type header.

6 Action View

Please refer to the Changelog for detailed changes.

6.1 Removals

Remove deprecated escape_whitelist from ActionView::Template::Handlers::ERB.
Remove deprecated find_all_anywhere from ActionView::Resolver.
Remove deprecated formats from ActionView::Template::HTML.
Remove deprecated formats from ActionView::Template::RawFile.
Remove deprecated formats from ActionView::Template::Text.
Remove deprecated find_file from ActionView::PathSet.
Remove deprecated rendered_format from ActionView::LookupContext.
Remove deprecated find_file from ActionView::ViewPaths.
Remove deprecated support to pass an object that is not a ActionView::LookupContext as the first argument in ActionView::Base#initialize.
Remove deprecated format argument ActionView::Base#initialize.
Remove deprecated ActionView::Template#refresh.
Remove deprecated ActionView::Template#original_encoding.
Remove deprecated ActionView::Template#variants.
Remove deprecated ActionView::Template#formats.
Remove deprecated ActionView::Template#virtual_path=.
Remove deprecated ActionView::Template#updated_at.
Remove deprecated updated_at argument required on ActionView::Template#initialize.
Remove deprecated ActionView::Template.finalize_compiled_template_methods.
Remove deprecated config.action_view.finalize_compiled_template_methods
Remove deprecated support to calling ActionView::ViewPaths#with_fallback with a block.
Remove deprecated support to passing absolute paths to render template:.
Remove deprecated support to passing relative paths to render file:.
Remove support to template handlers that don't accept two arguments.
Remove deprecated pattern argument in ActionView::Template::PathResolver.
Remove deprecated support to call private methods from object in some view helpers.

6.2 Deprecations

6.3 Notable changes

Require that ActionView::Base subclasses implement #compiled_method_container.
Make locals argument required on ActionView::Template#initialize.

7 Action Mailer

Please refer to the Changelog for detailed changes.

7.1 Removals

Remove deprecated ActionMailer::Base.receive in favor of Action Mailbox.

7.2 Deprecations

7.3 Notable changes

8 Active Record

Please refer to the Changelog for detailed changes.

8.1 Removals

Remove deprecated methods from ActiveRecord::ConnectionAdapters::DatabaseLimits.

column_name_length table_name_length columns_per_table indexes_per_table columns_per_multicolumn_index sql_query_length joins_per_query
Remove deprecated ActiveRecord::ConnectionAdapters::AbstractAdapter#supports_multi_insert?.
Remove deprecated ActiveRecord::ConnectionAdapters::AbstractAdapter#supports_foreign_keys_in_create?.
Remove deprecated ActiveRecord::ConnectionAdapters::PostgreSQLAdapter#supports_ranges?.
Remove deprecated ActiveRecord::Base#update_attributes and ActiveRecord::Base#update_attributes!.
Remove deprecated migrations_path argument in ActiveRecord::ConnectionAdapter::SchemaStatements#assume_migrated_upto_version.
Remove deprecated config.active_record.sqlite3.represent_boolean_as_integer.
Remove deprecated methods from ActiveRecord::DatabaseConfigurations.

fetch each first values []=
Remove deprecated ActiveRecord::Result#to_hash method.
Remove deprecated support for using unsafe raw SQL in ActiveRecord::Relation methods.

8.2 Deprecations

Deprecate ActiveRecord::Base.allow_unsafe_raw_sql.

8.3 Notable changes

MySQL: Uniqueness validator now respects default database collation, no longer enforce case sensitive comparison by default.
relation.create does no longer leak scope to class level querying methods in initialization block and callbacks.

Before:
```
User.where(name: "John").create do |john|
  User.find_by(name: "David") # => nil
end
```
User.where(name: "John").create do |john| User.find_by(name: "David") # => nil end
After:
```
User.where(name: "John").create do |john|
  User.find_by(name: "David") # => #<User name: "David", ...>
end
```
User.where(name: "John").create do |john| User.find_by(name: "David") # => #<User name: "David", ...> end
Named scope chain does no longer leak scope to class level querying methods.
```
class User < ActiveRecord::Base
  scope :david, -> { User.where(name: "David") }
end
```
class User < ActiveRecord::Base scope :david, -> { User.where(name: "David") } end
Before:
```
User.where(name: "John").david
# SELECT * FROM users WHERE name = 'John' AND name = 'David'
```
User.where(name: "John").david # SELECT * FROM users WHERE name = 'John' AND name = 'David'
After:
```
User.where(name: "John").david
# SELECT * FROM users WHERE name = 'David'
```
User.where(name: "John").david # SELECT * FROM users WHERE name = 'David'
where.not now generates NAND predicates instead of NOR.

Before:
```
 User.where.not(name: "Jon", role: "admin")
 # SELECT * FROM users WHERE name != 'Jon' AND role != 'admin'
```
User.where.not(name: "Jon", role: "admin") # SELECT * FROM users WHERE name != 'Jon' AND role != 'admin'
After:
```
 User.where.not(name: "Jon", role: "admin")
 # SELECT * FROM users WHERE NOT (name == 'Jon' AND role == 'admin')
```
User.where.not(name: "Jon", role: "admin") # SELECT * FROM users WHERE NOT (name == 'Jon' AND role == 'admin')

9 Active Storage

Please refer to the Changelog for detailed changes.

9.1 Removals

Remove deprecated support to pass :combine_options operations to ActiveStorage::Transformers::ImageProcessing.
Remove deprecated ActiveStorage::Transformers::MiniMagickTransformer.
Remove deprecated config.active_storage.queue.
Remove deprecated ActiveStorage::Downloading.

9.2 Deprecations

Deprecate Blob.create_after_upload in favor of Blob.create_and_upload. (Pull Request)

9.3 Notable changes

Add Blob.create_and_upload to create a new blob and upload the given io to the service. (Pull Request)

10 Active Model

Please refer to the Changelog for detailed changes.

10.1 Removals

10.2 Deprecations

10.3 Notable changes

Active Model's errors are now objects with an interface that allows your application to more easily handle and interact with errors thrown by models. The feature includes a query interface, enables more precise testing, and access to error details.

11 Active Support

Please refer to the Changelog for detailed changes.

11.1 Removals

Remove deprecated fallback to I18n.default_local when config.i18n.fallbacks is empty.
Remove deprecated LoggerSilence constant.
Remove deprecated ActiveSupport::LoggerThreadSafeLevel#after_initialize.
Remove deprecated Module#parent_name, Module#parent and Module#parents.
Remove deprecated file active_support/core_ext/module/reachable.
Remove deprecated file active_support/core_ext/numeric/inquiry.
Remove deprecated file active_support/core_ext/array/prepend_and_append.
Remove deprecated file active_support/core_ext/hash/compact.
Remove deprecated file active_support/core_ext/hash/transform_values.
Remove deprecated file active_support/core_ext/range/include_range.
Remove deprecated ActiveSupport::Multibyte::Chars#consumes? and ActiveSupport::Multibyte::Chars#normalize.
Remove deprecated ActiveSupport::Multibyte::Unicode.pack_graphemes, ActiveSupport::Multibyte::Unicode.unpack_graphemes, ActiveSupport::Multibyte::Unicode.normalize, ActiveSupport::Multibyte::Unicode.downcase, ActiveSupport::Multibyte::Unicode.upcase and ActiveSupport::Multibyte::Unicode.swapcase.
Remove deprecated ActiveSupport::Notifications::Instrumenter#end=.

11.2 Deprecations

Deprecate ActiveSupport::Multibyte::Unicode.default_normalization_form.

11.3 Notable changes

12 Active Job

Please refer to the Changelog for detailed changes.

12.1 Removals

12.2 Deprecations

Deprecate config.active_job.return_false_on_aborted_enqueue.

12.3 Notable changes

Return false when enqueuing a job is aborted.

13 Action Text

Please refer to the Changelog for detailed changes.

13.1 Removals

13.2 Deprecations

13.3 Notable changes

Add method to confirm rich text content existence by adding ? after name of the rich text attribute. (Pull Request)
Add fill_in_rich_text_area system test case helper to find a trix editor and fill it with given HTML content. (Pull Request)
Add ActionText::FixtureSet.attachment to generate <action-text-attachment> elements in database fixtures. (Pull Request)

14 Action Mailbox

Please refer to the Changelog for detailed changes.

14.1 Removals

14.2 Deprecations

14.3 Notable changes

15 Ruby on Rails Guides

Please refer to the Changelog for detailed changes.

15.1 Notable changes

16 Credits

See the full list of contributors to Rails for the many people who spent many hours making Rails, the stable and robust framework it is. Kudos to all of them.

Feedback

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