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diff --git a/guides/source/4_2_release_notes.md b/guides/source/4_2_release_notes.md new file mode 100644 index 0000000000..dad973cf5e --- /dev/null +++ b/guides/source/4_2_release_notes.md @@ -0,0 +1,736 @@ +Ruby on Rails 4.2 Release Notes +=============================== + +Highlights in Rails 4.2: + +* Active Job, Action Mailer #deliver_later +* Adequate Record +* Web Console +* Foreign key support + +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/master) in the main Rails +repository on GitHub. + +-------------------------------------------------------------------------------- + +NOTE: This document is a work in progress, please help to improve this by sending +a [pull request](https://github.com/rails/rails/edit/master/guides/source/4_2_release_notes.md). + +Upgrading to Rails 4.2 +---------------------- + +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 4.1 in case you +haven't and make sure your application still runs as expected before attempting +to upgrade to Rails 4.2. 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-4-1-to-rails-4-2) +guide. + + +Major Features +-------------- + +### Active Job, Action Mailer #deliver_later + +Active Job is a new framework in Rails 4.2. It is an adapter layer on top of +queuing systems like [Resque](https://github.com/resque/resque), [Delayed Job](https://github.com/collectiveidea/delayed_job), [Sidekiq](https://github.com/mperham/sidekiq), and more. You can write your +jobs with the Active Job API, and it'll run on all these queues with no changes +(it comes pre-configured with an inline runner). + +Building on top of Active Job, Action Mailer now comes with a `#deliver_later` +method, which adds your email to be sent as a job to a queue, so it doesn't +bog down the controller or model. + +The new GlobalID library makes it easy to pass Active Record objects to jobs by +serializing them in a generic form. This means you no longer have to manually +pack and unpack your Active Records by passing ids. Just give the job the +straight Active Record object, and it'll serialize it using GlobalID, and +deserialize it at run time. + +### Adequate Record + +Rails 4.2 comes with a performance improvement feature called Adequate Record +for Active Record. A lot of common queries are now up to twice as fast in Rails +4.2! + +TODO: add some technical details + +### Web Console + +New applications generated from Rails 4.2 now come with the Web Console gem by +default. + +Web Console is a set of debugging tools for your Rails application. It will add +an interactive console on every error page, a `console` view helper and a VT100 +compatible terminal. + +The interactive console on the error pages lets you execute code where the +exception originated. It's quite handy to introspect the state that led to the +error. + +The `console` view helper launches an interactive console within the context of +the view where it is invoked. + +Finally, you can launch a VT100 terminal that runs `rails console`. If you need +to create or modify existing test data, you can do that straight from the +browser. + +### Foreign key support + +The migration DSL now supports adding and removing foreign keys. They are dumped +to `schema.rb` as well. At this time, only the `mysql`, `mysql2` and `postgresql` +adapters support foreign keys. + +```ruby +# add a foreign key to `articles.author_id` referencing `authors.id` +add_foreign_key :articles, :authors + +# add a foreign key to `articles.author_id` referencing `users.lng_id` +add_foreign_key :articles, :users, column: :author_id, primary_key: "lng_id" + +# remove the foreign key on `accounts.branch_id` +remove_foreign_key :accounts, :branches + +# remove the foreign key on `accounts.owner_id` +remove_foreign_key :accounts, column: :owner_id +``` + +See the API documentation on +[add_foreign_key](http://api.rubyonrails.org/v4.2.0/classes/ActiveRecord/ConnectionAdapters/SchemaStatements.html#method-i-add_foreign_key) +and +[remove_foreign_key](http://api.rubyonrails.org/v4.2.0/classes/ActiveRecord/ConnectionAdapters/SchemaStatements.html#method-i-remove_foreign_key) +for a full description. + + +Incompatibilities +----------------- + +Previously deprecated functionality has been removed. Please refer to the +individual components for new deprecations in this release. + +The following changes may require immediate action upon upgrade. + +### `respond_with` / class-level `respond_to` + +`respond_with` and the corresponding class-level `respond_to` have been moved to +the `responders` gem. To use the following, add `gem 'responders', '~> 2.0'` to +your Gemfile: + +```ruby +# app/controllers/users_controller.rb + +class UsersController < ApplicationController + respond_to :html, :json + + def show + @user = User.find(params[:id]) + respond_with @user + end +end +``` + +Instance-level `respond_to` is unaffected: + +```ruby +# app/controllers/users_controller.rb + +class UsersController < ApplicationController + def show + @user = User.find(params[:id]) + respond_to do |format| + format.html + format.json { render json: @user } + end + end +end +``` + +### Production logging + +The default log level in the `production` environment is now `:debug`. This +makes it consistent with the other environments, and ensures plenty of +information is available to diagnose problems. + +It can be returned to the previous level, `:info`, in the environment +configuration: + +```ruby +# config/environments/production.rb + +# Decrease the log volume. +config.log_level = :info +``` + +### HTML Sanitizer + +The HTML sanitizer has been replaced with a new, more robust, implementation +built upon Loofah and Nokogiri. The new sanitizer is more secure and its +sanitization is more powerful and flexible. + +With a new sanitization algorithm, the sanitized output will change for certain +pathological inputs. + +If you have particular need for the exact output of the old sanitizer, you can +add `rails-deprecated_sanitizer` to your Gemfile, and it will automatically +replace the new implementation. Because it is opt-in, the legacy gem will not +give deprecation warnings. + +`rails-deprecated_sanitizer` will be supported for Rails 4.2 only; it will not +be maintained for Rails 5.0. + +See [the blog post](http://blog.plataformatec.com.br/2014/07/the-new-html-sanitizer-in-rails-4-2/) +for more detail on the changes in the new sanitizer. + +### `assert_select` + +`assert_select` is now based on Nokogiri, making it (TODO: betterer). + +As a result, some previously-valid selectors are now unsupported. If your +application is using any of these spellings, you will need to update them: + +* Values in attribute selectors may need to be quoted if they contain + non-alphanumeric characters. + + ``` + a[href=/] => a[href="/"] + a[href$=/] => a[href$="/"] + ``` + +* DOMs built from HTML source containing invalid HTML with improperly + nested elements may differ. + + For example: + + ``` ruby + # content: <div><i><p></i></div> + + # before: + assert_select('div > i') # => true + assert_select('div > p') # => false + assert_select('i > p') # => true + + # now: + assert_select('div > i') # => true + assert_select('div > p') # => true + assert_select('i > p') # => false + ``` + +* If the data selected contains entities, the value selected for comparison + used to be raw (e.g. `AT&T`), and now is evaluated + (e.g. `AT&T`). + + ``` ruby + # content: <p>AT&T</p> + + # before: + assert_select('p', 'AT&T') # => true + assert_select('p', 'AT&T') # => false + + # now: + assert_select('p', 'AT&T') # => true + assert_select('p', 'AT&T') # => false + ``` + + +Railties +-------- + +Please refer to the [Changelog][railties] for detailed changes. + +### Removals + +* The `rails application` command has been removed without replacement. + ([Pull Request](https://github.com/rails/rails/pull/11616)) + +### Deprecations + +* Deprecated `Rails::Rack::LogTailer` without replacement. + ([Commit](https://github.com/rails/rails/commit/84a13e019e93efaa8994b3f8303d635a7702dbce)) + +### Notable changes + +* Introduced `web-console` in the default application Gemfile. + ([Pull Request](https://github.com/rails/rails/pull/11667)) + +* Added a `required` option to the model generator for associations. + ([Pull Request](https://github.com/rails/rails/pull/16062)) + +* Introduced an `after_bundle` callback for use in Rails templates. + ([Pull Request](https://github.com/rails/rails/pull/16359)) + +* Introduced the `x` namespace for defining custom configuration options: + + ```ruby + # config/environments/production.rb + config.x.payment_processing.schedule = :daily + config.x.payment_processing.retries = 3 + config.x.super_debugger = true + ``` + + These options are then available through the configuration object: + + ```ruby + Rails.configuration.x.payment_processing.schedule # => :daily + Rails.configuration.x.payment_processing.retries # => 3 + Rails.configuration.x.super_debugger # => true + ``` + + ([Commit](https://github.com/rails/rails/commit/611849772dd66c2e4d005dcfe153f7ce79a8a7db)) + +* Introduced `Rails::Application.config_for` to load a configuration for the + current environment. + + ```ruby + # config/exception_notification.yml: + production: + url: http://127.0.0.1:8080 + namespace: my_app_production + development: + url: http://localhost:3001 + namespace: my_app_development + + # config/production.rb + MyApp::Application.configure do + config.middleware.use ExceptionNotifier, config_for(:exception_notification) + end + ``` + + ([Pull Request](https://github.com/rails/rails/pull/16129)) + +* Introduced a `--skip-gems` option in the app generator to skip gems such as + `turbolinks` and `coffee-rails` that do not have their own specific flags. + ([Commit](https://github.com/rails/rails/commit/10565895805887d4faf004a6f71219da177f78b7)) + +* Introduced a `bin/setup` script to enable automated setup code when + bootstrapping an application. + ([Pull Request](https://github.com/rails/rails/pull/15189)) + +* Changed default value for `config.assets.digest` to `true` in development. + ([Pull Request](https://github.com/rails/rails/pull/15155)) + +* Introduced an API to register new extensions for `rake notes`. + ([Pull Request](https://github.com/rails/rails/pull/14379)) + +* Introduced `Rails.gem_version` as a convenience method to return + `Gem::Version.new(Rails.version)`. + ([Pull Request](https://github.com/rails/rails/pull/14101)) + + +Action Pack +----------- + +Please refer to the [Changelog][action-pack] for detailed changes. + +### Removals + +* `respond_with` and the class-level `respond_to` were removed from Rails and + moved to the `responders` gem (version 2.0). Add `gem 'responders', '~> 2.0'` + to your `Gemfile` to continue using these features. + ([Pull Request](https://github.com/rails/rails/pull/16526)) + +* Removed deprecated `AbstractController::Helpers::ClassMethods::MissingHelperError` + in favor of `AbstractController::Helpers::MissingHelperError`. + ([Commit](https://github.com/rails/rails/commit/a1ddde15ae0d612ff2973de9cf768ed701b594e8)) + +### Deprecations + +* Deprecated `assert_tag`, `assert_no_tag`, `find_tag` and `find_all_tag` in + favor of `assert_select`. + ([Commit](https://github.com/rails/rails-dom-testing/commit/b12850bc5ff23ba4b599bf2770874dd4f11bf750)) + +* Deprecated support for setting the `:to` option of a router to a symbol or a + string that does not contain a `#` character: + + ```ruby + get '/posts', to: MyRackApp => (No change necessary) + get '/posts', to: 'post#index' => (No change necessary) + get '/posts', to: 'posts' => get '/posts', controller: :posts + get '/posts', to: :index => get '/posts', action: :index + ``` + + ([Commit](https://github.com/rails/rails/commit/cc26b6b7bccf0eea2e2c1a9ebdcc9d30ca7390d9)) + +### Notable changes + +* Rails will now automatically include the template's digest in ETags. + ([Pull Request](https://github.com/rails/rails/pull/16527)) + +* `render nothing: true` or rendering a `nil` body no longer add a single + space padding to the response body. + ([Pull Request](https://github.com/rails/rails/pull/14883)) + +* Introduced the `always_permitted_parameters` option to configure which + parameters are permitted globally. The default value of this configuration + is `['controller', 'action']`. + ([Pull Request](https://github.com/rails/rails/pull/15933)) + +* The `*_filter` family methods have been removed from the documentation. Their + usage is discouraged in favor of the `*_action` family methods: + + ``` + after_filter => after_action + append_after_filter => append_after_action + append_around_filter => append_around_action + append_before_filter => append_before_action + around_filter => around_action + before_filter => before_action + prepend_after_filter => prepend_after_action + prepend_around_filter => prepend_around_action + prepend_before_filter => prepend_before_action + skip_after_filter => skip_after_action + skip_around_filter => skip_around_action + skip_before_filter => skip_before_action + skip_filter => skip_action_callback + ``` + + If your application currently depends on these methods, you should use the + replacement `*_action` methods instead. These methods will be deprecated in + the future and will eventually be removed from Rails. + + (Commit [1](https://github.com/rails/rails/commit/6c5f43bab8206747a8591435b2aa0ff7051ad3de), + [2](https://github.com/rails/rails/commit/489a8f2a44dc9cea09154ee1ee2557d1f037c7d4)) + +* Added HTTP method `MKCALENDAR` from RFC-4791 + ([Pull Request](https://github.com/rails/rails/pull/15121)) + +* `*_fragment.action_controller` notifications now include the controller + and action name in the payload. + ([Pull Request](https://github.com/rails/rails/pull/14137)) + +* Segments that are passed into URL helpers are now automatically escaped. + ([Commit](https://github.com/rails/rails/commit/5460591f0226a9d248b7b4f89186bd5553e7768f)) + +* Improved the Routing Error page with fuzzy matching for route search. + ([Pull Request](https://github.com/rails/rails/pull/14619)) + +* Added an option to disable logging of CSRF failures. + ([Pull Request](https://github.com/rails/rails/pull/14280)) + +* When the Rails server is set to serve static assets, gzip assets will now be + served if the client supports it and a pre-generated gzip file (.gz) is on disk. + By default the asset pipeline generates `.gz` files for all compressible assets. + Serving gzip files minimizes data transfer and speeds up asset requests. Always + [use a CDN](http://guides.rubyonrails.org/asset_pipeline.html#cdns) if you are + serving assets from your Rails server in production. + ([Pull Request](https://github.com/rails/rails/pull/16466)) + +* The way `assert_select` works has changed; specifically a different library + is used to interpret css selectors, build the transient DOM that the + selectors are applied against, and to extract the data from that DOM. These + changes should only affect edge cases. Examples: + * Values in attribute selectors may need to be quoted if they contain + non-alphanumeric characters. + * DOMs built from HTML source containing invalid HTML with improperly + nested elements may differ. + * If the data selected contains entities, the value selected for comparison + used to be raw (e.g. `AT&T`), and now is evaluated + (e.g. `AT&T`). + + +Action View +------------- + +Please refer to the [Changelog][action-view] for detailed changes. + +### Deprecations + +* Deprecated `AbstractController::Base.parent_prefixes`. + Override `AbstractController::Base.local_prefixes` when you want to change + where to find views. + ([Pull Request](https://github.com/rails/rails/pull/15026)) + +* Deprecated `ActionView::Digestor#digest(name, format, finder, options = {})`. + Arguments should be passed as a hash instead. + ([Pull Request](https://github.com/rails/rails/pull/14243)) + +### Notable changes + +* Introduced a `#{partial_name}_iteration` special local variable for use with + partials that are rendered with a collection. It provides access to the + current state of the iteration via the `#index`, `#size`, `#first?` and + `#last?` methods. + ([Pull Request](https://github.com/rails/rails/pull/7698)) + +* The form helpers no longer generate a `<div>` element with inline CSS around + the hidden fields. + ([Pull Request](https://github.com/rails/rails/pull/14738)) + +* Placeholder I18n follows the same convention as `label` I18n. + ([Pull Request](https://github.com/rails/rails/pull/16438)) + + +Action Mailer +------------- + +Please refer to the [Changelog][action-mailer] for detailed changes. + +### Deprecations + +* Deprecated `*_path` helpers in mailers. Always use `*_url` helpers instead. + ([Pull Request](https://github.com/rails/rails/pull/15840)) + +* Deprecated `deliver` / `deliver!` in favour of `deliver_now` / `deliver_now!`. + ([Pull Request](https://github.com/rails/rails/pull/16582)) + +### Notable changes + +* Introduced `deliver_later` which enqueues a job on the application's queue + to deliver emails asynchronously. + ([Pull Request](https://github.com/rails/rails/pull/16485)) + +* Added the `show_previews` configuration option for enabling mailer previews + outside of the development environment. + ([Pull Request](https://github.com/rails/rails/pull/15970)) + + +Active Record +------------- + +Please refer to the [Changelog][active-record] for detailed changes. + +### Removals + +* Removed `cache_attributes` and friends. All attributes are cached. + ([Pull Request](https://github.com/rails/rails/pull/15429)) + +* Removed deprecated method `ActiveRecord::Base.quoted_locking_column`. + ([Pull Request](https://github.com/rails/rails/pull/15612)) + +* Removed deprecated `ActiveRecord::Migrator.proper_table_name`. Use the + `proper_table_name` instance method on `ActiveRecord::Migration` instead. + ([Pull Request](https://github.com/rails/rails/pull/15512)) + +* Removed unused `:timestamp` type. Transparently alias it to `:datetime` + in all cases. Fixes inconsistencies when column types are sent outside of + `ActiveRecord`, such as for XML serialization. + ([Pull Request](https://github.com/rails/rails/pull/15184)) + +### Deprecations + +* Deprecated swallowing of errors inside `after_commit` and `after_rollback`. + ([Pull Request](https://github.com/rails/rails/pull/16537)) + +* Deprecated calling `DatabaseTasks.load_schema` without a connection. Use + `DatabaseTasks.load_schema_current` instead. + ([Commit](https://github.com/rails/rails/commit/f15cef67f75e4b52fd45655d7c6ab6b35623c608)) + +* Deprecated `Reflection#source_macro` without replacement as it is no longer + needed in Active Record. + ([Pull Request](https://github.com/rails/rails/pull/16373)) + +* Deprecated broken support for automatic detection of counter caches on + `has_many :through` associations. You should instead manually specify the + counter cache on the `has_many` and `belongs_to` associations for the + through records. + ([Pull Request](https://github.com/rails/rails/pull/15754)) + +* Deprecated `serialized_attributes` without replacement. + ([Pull Request](https://github.com/rails/rails/pull/15704)) + +* Deprecated returning `nil` from `column_for_attribute` when no column + exists. It will return a null object in Rails 5.0 + ([Pull Request](https://github.com/rails/rails/pull/15878)) + +* Deprecated using `.joins`, `.preload` and `.eager_load` with associations + that depends on the instance state (i.e. those defined with a scope that + takes an argument) without replacement. + ([Commit](https://github.com/rails/rails/commit/ed56e596a0467390011bc9d56d462539776adac1)) + +* Deprecated passing Active Record objects to `.find` or `.exists?`. Call + `#id` on the objects first. + (Commit [1](https://github.com/rails/rails/commit/d92ae6ccca3bcfd73546d612efaea011270bd270), + [2](https://github.com/rails/rails/commit/d35f0033c7dec2b8d8b52058fb8db495d49596f7)) + +* Deprecated half-baked support for PostgreSQL range values with excluding + beginnings. We currently map PostgreSQL ranges to Ruby ranges. This conversion + is not fully possible because the Ruby range does not support excluded + beginnings. + + The current solution of incrementing the beginning is not correct + and is now deprecated. For subtypes where we don't know how to increment + (e.g. `#succ` is not defined) it will raise an `ArgumentError` for ranges + with excluding beginnings. + + ([Commit](https://github.com/rails/rails/commit/91949e48cf41af9f3e4ffba3e5eecf9b0a08bfc3)) + +### Notable changes + +* The PostgreSQL adapter now supports the `JSONB` datatype in PostgreSQL 9.4+. + ([Pull Request](https://github.com/rails/rails/pull/16220)) + +* The `#references` method in migrations now supports a `type` option for + specifying the type of the foreign key (e.g. `:uuid`). + ([Pull Request](https://github.com/rails/rails/pull/16231)) + +* Added a `:required` option to singular associations, which defines a + presence validation on the association. + ([Pull Request](https://github.com/rails/rails/pull/16056)) + +* Introduced `ActiveRecord::Base#validate!` that raises `RecordInvalid` if the + record is invalid. + ([Pull Request](https://github.com/rails/rails/pull/8639)) + +* `ActiveRecord::Base#reload` now behaves the same as `m = Model.find(m.id)`, + meaning that it no longer retains the extra attributes from custom + `select`s. + ([Pull Request](https://github.com/rails/rails/pull/15866)) + +* Introduced the `bin/rake db:purge` task to empty the database for the + current environment. + ([Commit](https://github.com/rails/rails/commit/e2f232aba15937a4b9d14bd91e0392c6d55be58d)) + +* `ActiveRecord::Dirty` now detects in-place changes to mutable values. + Serialized attributes on ActiveRecord models will no longer save when + unchanged. This also works with other types such as string columns and json + columns on PostgreSQL. + (Pull Requests [1](https://github.com/rails/rails/pull/15674), + [2](https://github.com/rails/rails/pull/15786), + [3](https://github.com/rails/rails/pull/15788)) + +* Added support for `#pretty_print` in `ActiveRecord::Base` objects. + ([Pull Request](https://github.com/rails/rails/pull/15172)) + +* PostgreSQL and SQLite adapters no longer add a default limit of 255 + characters on string columns. + ([Pull Request](https://github.com/rails/rails/pull/14579)) + +* `sqlite3:///some/path` now resolves to the absolute system path + `/some/path`. For relative paths, use `sqlite3:some/path` instead. + (Previously, `sqlite3:///some/path` resolved to the relative path + `some/path`. This behaviour was deprecated on Rails 4.1). + ([Pull Request](https://github.com/rails/rails/pull/14569)) + +* Introduced `#validate` as an alias for `#valid?`. + ([Pull Request](https://github.com/rails/rails/pull/14456)) + +* `#touch` now accepts multiple attributes to be touched at once. + ([Pull Request](https://github.com/rails/rails/pull/14423)) + +* Added support for fractional seconds for MySQL 5.6 and above. + (Pull Request [1](https://github.com/rails/rails/pull/8240), + [2](https://github.com/rails/rails/pull/14359)) + +* Added support for the `citext` column type in PostgreSQL adapter. + ([Pull Request](https://github.com/rails/rails/pull/12523)) + +* Added support for user-created range types in PostgreSQL adapter. + ([Commit](https://github.com/rails/rails/commit/4cb47167e747e8f9dc12b0ddaf82bdb68c03e032)) + + +Active Model +------------ + +Please refer to the [Changelog][active-model] for detailed changes. + +### Removals + +* Removed deprecated `Validator#setup` without replacement. + ([Pull Request](https://github.com/rails/rails/pull/10716)) + +### Deprecations + +* Deprecated `reset_#{attribute}` in favor of `restore_#{attribute}`. + ([Pull Request](https://github.com/rails/rails/pull/16180)) + +* Deprecated `ActiveModel::Dirty#reset_changes` in favor of + `#clear_changes_information`. + ([Pull Request](https://github.com/rails/rails/pull/16180)) + +### Notable changes + +* Introduced the `restore_attributes` method in `ActiveModel::Dirty` to restore + the changed (dirty) attributes to their previous values. + (Pull Request [1](https://github.com/rails/rails/pull/14861), + [2](https://github.com/rails/rails/pull/16180)) + +* `has_secure_password` no longer disallow blank passwords (i.e. passwords + that contains only spaces) by default. + ([Pull Request](https://github.com/rails/rails/pull/16412)) + +* `has_secure_password` now verifies that the given password is less than 72 + characters if validations are enabled. + ([Pull Request](https://github.com/rails/rails/pull/15708)) + +* Introduced `#validate` as an alias for `#valid?`. + ([Pull Request](https://github.com/rails/rails/pull/14456)) + + +Active Support +-------------- + +Please refer to the [Changelog][active-support] for detailed changes. + +### Removals + +* Removed deprecated `Numeric#ago`, `Numeric#until`, `Numeric#since`, + `Numeric#from_now`. + ([Commit](https://github.com/rails/rails/commit/f1eddea1e3f6faf93581c43651348f48b2b7d8bb)) + +* Removed deprecated string based terminators for `ActiveSupport::Callbacks`. + ([Pull Request](https://github.com/rails/rails/pull/15100)) + +### Deprecations + +* Deprecated `Kernel#silence_stderr`, `Kernel#capture` and `Kernel#quietly` + without replacement. + ([Pull Request](https://github.com/rails/rails/pull/13392)) + +* Deprecated `Class#superclass_delegating_accessor`, use + `Class#class_attribute` instead. + ([Pull Request](https://github.com/rails/rails/pull/14271)) + +* Deprecated `ActiveSupport::SafeBuffer#prepend!` as + `ActiveSupport::SafeBuffer#prepend` now performs the same function. + ([Pull Request](https://github.com/rails/rails/pull/14529)) + +### Notable changes + +* The `travel_to` test helper now truncates the `usec` component to 0. + ([Commit](https://github.com/rails/rails/commit/9f6e82ee4783e491c20f5244a613fdeb4024beb5)) + +* `ActiveSupport::TestCase` now randomizes the order that test cases are ran + by default. + ([Commit](https://github.com/rails/rails/commit/6ffb29d24e05abbd9ffe3ea974140d6c70221807)) + +* Introduced `Object#itself` as an identity function. + (Commit [1](https://github.com/rails/rails/commit/702ad710b57bef45b081ebf42e6fa70820fdd810), + [2](https://github.com/rails/rails/commit/64d91122222c11ad3918cc8e2e3ebc4b0a03448a)) + +* `Object#with_options` can now be used without an explicit receiver. + ([Pull Request](https://github.com/rails/rails/pull/16339)) + +* Introduced `String#truncate_words` to truncate a string by a number of words. + ([Pull Request](https://github.com/rails/rails/pull/16190)) + +* Added `Hash#transform_values` and `Hash#transform_values!` to simplify a + common pattern where the values of a hash must change, but the keys are left + the same. + ([Pull Request](https://github.com/rails/rails/pull/15819)) + +* The `humanize` inflector helper now strips any leading underscores. + ([Commit](https://github.com/rails/rails/commit/daaa21bc7d20f2e4ff451637423a25ff2d5e75c7)) + +* Introduced `Concern#class_methods` as an alternative to + `module ClassMethods`, as well as `Kernel#concern` to avoid the + `module Foo; extend ActiveSupport::Concern; end` boilerplate. + ([Commit](https://github.com/rails/rails/commit/b16c36e688970df2f96f793a759365b248b582ad)) + + +Credits +------- + +See the +[full list of contributors to Rails](http://contributors.rubyonrails.org/) for +the many people who spent many hours making Rails the stable and robust +framework it is today. Kudos to all of them. + +[railties]: https://github.com/rails/rails/blob/4-2-stable/railties/CHANGELOG.md +[action-pack]: https://github.com/rails/rails/blob/4-2-stable/actionpack/CHANGELOG.md +[action-view]: https://github.com/rails/rails/blob/4-2-stable/actionview/CHANGELOG.md +[action-mailer]: https://github.com/rails/rails/blob/4-2-stable/actionmailer/CHANGELOG.md +[active-record]: https://github.com/rails/rails/blob/4-2-stable/activerecord/CHANGELOG.md +[active-model]: https://github.com/rails/rails/blob/4-2-stable/activemodel/CHANGELOG.md +[active-support]: https://github.com/rails/rails/blob/4-2-stable/activesupport/CHANGELOG.md |