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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..366d9d26b4 --- /dev/null +++ b/guides/source/4_2_release_notes.md @@ -0,0 +1,855 @@ +**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.** + +Ruby on Rails 4.2 Release Notes +=============================== + +Highlights in Rails 4.2: + +* Active Job +* Asynchronous mails +* Adequate Record +* Web Console +* Foreign key support + +These release notes cover only the major changes. To learn about other +features, bug fixes, and changes, please refer to the changelogs or check out +the [list of commits](https://github.com/rails/rails/commits/4-2-stable) in +the main Rails repository on GitHub. + +-------------------------------------------------------------------------------- + +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 guide [Upgrading Ruby on +Rails](upgrading_ruby_on_rails.html#upgrading-from-rails-4-1-to-rails-4-2). + + +Major Features +-------------- + +### Active Job + +Active Job is a new framework in Rails 4.2. It is a common interface 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. + +Jobs written with the Active Job API run on any of the supported queues thanks +to their respective adapters. Active Job comes pre-configured with an inline +runner that executes jobs right away. + +Jobs often need to take Active Record objects as arguments. Active Job passes +object references as URIs (uniform resource identifiers) instead of marshaling +the object itself. The new [Global ID](https://github.com/rails/globalid) +library builds URIs and looks up the objects they reference. Passing Active +Record objects as job arguments just works by using Global ID internally. + +For example, if `trashable` is an Active Record object, then this job runs +just fine with no serialization involved: + +```ruby +class TrashableCleanupJob < ActiveJob::Base + def perform(trashable, depth) + trashable.cleanup(depth) + end +end +``` + +See the [Active Job Basics](active_job_basics.html) guide for more +information. + +### Asynchronous Mails + +Building on top of Active Job, Action Mailer now comes with a `deliver_later` +method that sends emails via the queue, so it doesn't block the controller or +model if the queue is asynchronous (the default inline queue blocks). + +Sending emails right away is still possible with `deliver_now`. + +### Adequate Record + +Adequate Record is a set of performance improvements in Active Record that makes +common `find` and `find_by` calls and some association queries up to 2x faster. + +It works by caching common SQL queries as prepared statements and reusing them +on similar calls, skipping most of the query-generation work on subsequent +calls. For more details, please refer to [Aaron Patterson's blog +post](http://tenderlovemaking.com/2014/02/19/adequaterecord-pro-like-activerecord.html). + +Active Record will automatically take advantage of this feature on +supported operations without any user involvement or code changes. Here are +some examples of supported operations: + +```ruby +Post.find(1) # First call generates and cache the prepared statement +Post.find(2) # Subsequent calls reuse the cached prepared statement + +Post.find_by_title('first post') +Post.find_by_title('second post') + +Post.find_by(title: 'first post') +Post.find_by(title: 'second post') + +post.comments +post.comments(true) +``` + +It's important to highlight that, as the examples above suggest, the prepared +statements do not cache the values passed in the method calls; rather, they +have placeholders for them. + +Caching is not used in the following scenarios: + +- The model has a default scope +- The model uses single table inheritance +- `find` with a list of ids, e.g.: + + ```ruby + # not cached + Post.find(1, 2, 3) + Post.find([1,2]) + ``` + +- `find_by` with SQL fragments: + + ```ruby + Post.find_by('published_at < ?', 2.weeks.ago) + ``` + +### Web Console + +New applications generated with Rails 4.2 now come with the [Web +Console](https://github.com/rails/web-console) gem by default. Web Console adds +an interactive Ruby console on every error page and provides a `console` view +and controller helpers. + +The interactive console on error pages lets you execute code in the context of +the place where the exception originated. The `console` helper, if called +anywhere in a view or controller, launches an interactive console with the final +context, once rendering has completed. + +### 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. + +### `render` with a String Argument + +Previously, calling `render "foo/bar"` in a controller action was equivalent to +`render file: "foo/bar"`. In Rails 4.2, this has been changed to mean +`render template: "foo/bar"` instead. If you need to render a file, please +change your code to use the explicit form (`render file: "foo/bar"`) instead. + +### `respond_with` / Class-Level `respond_to` + +`respond_with` and the corresponding class-level `respond_to` have been moved +to the [responders](https://github.com/plataformatec/responders) gem. Add +`gem 'responders', '~> 2.0'` to your Gemfile to use it: + +```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 +``` + +### Default Host for `rails server` + +Due to a [change in Rack](https://github.com/rack/rack/commit/28b014484a8ac0bbb388e7eaeeef159598ec64fc), +`rails server` now listens on `localhost` instead of `0.0.0.0` by default. This +should have minimal impact on the standard development workflow as both +http://127.0.0.1:3000 and http://localhost:3000 will continue to work as before +on your own machine. + +However, with this change you will no longer be able to access the Rails +server from a different machine, for example if your development environment +is in a virtual machine and you would like to access it from the host machine. +In such cases, please start the server with `rails server -b 0.0.0.0` to +restore the old behavior. + +If you do this, be sure to configure your firewall properly such that only +trusted machines on your network can access your development server. + +### HTML Sanitizer + +The HTML sanitizer has been replaced with a new, more robust, implementation +built upon [Loofah](https://github.com/flavorjones/loofah) and +[Nokogiri](https://github.com/sparklemotion/nokogiri). The new sanitizer is +more secure and its sanitization is more powerful and flexible. + +Due to the new algorithm, the sanitized output may be different for certain +pathological inputs. + +If you have a particular need for the exact output of the old sanitizer, you +can add the [rails-deprecated_sanitizer](https://github.com/kaspth/rails-deprecated_sanitizer) +gem to the `Gemfile`, to have the old behavior. The gem does not issue +deprecation warnings because it is opt-in. + +`rails-deprecated_sanitizer` will be supported for Rails 4.2 only; it will not +be maintained for Rails 5.0. + +See [this blog post](http://blog.plataformatec.com.br/2014/07/the-new-html-sanitizer-in-rails-4-2/) +for more details on the changes in the new sanitizer. + +### `assert_select` + +`assert_select` is now based on [Nokogiri](https://github.com/sparklemotion/nokogiri). +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. + + ``` + # before + a[href=/] + a[href$=/] + + # now + a[href="/"] + a[href$="/"] + ``` + +* 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 `--skip-action-view` option has been removed from the + app generator. ([Pull Request](https://github.com/rails/rails/pull/17042)) + +* The `rails application` command has been removed without replacement. + ([Pull Request](https://github.com/rails/rails/pull/11616)) + +### Deprecations + +* Deprecated missing `config.log_level` for production environments. + ([Pull Request](https://github.com/rails/rails/pull/16622)) + +* Deprecated `rake test:all` in favor of `rake test` as it now run all tests + in the `test` folder. + ([Pull Request](https://github.com/rails/rails/pull/17348)) + +* Deprecated `rake test:all:db` in favor of `rake test:db`. + ([Pull Request](https://github.com/rails/rails/pull/17348)) + +* 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 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 + Rails.application.configure do + config.middleware.use ExceptionNotifier, config_for(:exception_notification) + end + ``` + + ([Pull Request](https://github.com/rails/rails/pull/16129)) + +* Introduced a `--skip-turbolinks` option in the app generator to not generate + turbolinks integration. + ([Commit](https://github.com/rails/rails/commit/bf17c8a531bc8059d50ad731398002a3e7162a7d)) + +* Introduced a `bin/setup` script as a convention for automated setup code when + bootstrapping an application. + ([Pull Request](https://github.com/rails/rails/pull/15189)) + +* Changed the 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 an `after_bundle` callback for use in Rails templates. + ([Pull Request](https://github.com/rails/rails/pull/16359)) + +* 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` have been 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), + [More Details](http://guides.rubyonrails.org/upgrading_ruby_on_rails.html#responders)) + +* Removed deprecated `AbstractController::Helpers::ClassMethods::MissingHelperError` + in favor of `AbstractController::Helpers::MissingHelperError`. + ([Commit](https://github.com/rails/rails/commit/a1ddde15ae0d612ff2973de9cf768ed701b594e8)) + +### Deprecations + +* Deprecated the `only_path` option on `*_path` helpers. + ([Commit](https://github.com/rails/rails/commit/aa1fadd48fb40dd9396a383696134a259aa59db9)) + +* 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)) + +* Deprecated support for string keys in URL helpers: + + ```ruby + # bad + root_path('controller' => 'posts', 'action' => 'index') + + # good + root_path(controller: 'posts', action: 'index') + ``` + + ([Pull Request](https://github.com/rails/rails/pull/17743)) + +### Notable changes + +* The `*_filter` family of methods have been removed from the documentation. Their + usage is discouraged in favor of the `*_action` family of 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)) + +* `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)) + +* Rails now automatically includes the template's digest in ETags. + ([Pull Request](https://github.com/rails/rails/pull/16527)) + +* Segments that are passed into URL helpers are now automatically escaped. + ([Commit](https://github.com/rails/rails/commit/5460591f0226a9d248b7b4f89186bd5553e7768f)) + +* 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)) + +* Added the HTTP method `MKCALENDAR` from [RFC 4791](https://tools.ietf.org/html/rfc4791). + ([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)) + +* 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)) + +* When calling the `process` helpers in an integration test the path needs to have + a leading slash. Previously you could omit it but that was a byproduct of the + implementation and not an intentional feature, e.g.: + + ```ruby + test "list all posts" do + get "/posts" + assert_response :success + end + ``` + +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 + +* `render "foo/bar"` now expands to `render template: "foo/bar"` instead of + `render file: "foo/bar"`. + ([Pull Request](https://github.com/rails/rails/pull/16888)) + +* 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)) + +* 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)) + +* 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 favor of `deliver_now` / `deliver_now!`. + ([Pull Request](https://github.com/rails/rails/pull/16582)) + +### Notable changes + +* `link_to` and `url_for` generate absolute URLs by default in templates, + it is no longer needed to pass `only_path: false`. + ([Commit](https://github.com/rails/rails/commit/9685080a7677abfa5d288a81c3e078368c6bb67c)) + +* 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 + Active Record, 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 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 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 Ruby ranges do 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)) + +* Deprecated calling `DatabaseTasks.load_schema` without a connection. Use + `DatabaseTasks.load_schema_current` instead. + ([Commit](https://github.com/rails/rails/commit/f15cef67f75e4b52fd45655d7c6ab6b35623c608)) + +* Deprecated `sanitize_sql_hash_for_conditions` without replacement. Using a + `Relation` for performing queries and updates is the preferred API. + ([Commit](https://github.com/rails/rails/commit/d5902c9e)) + +* Deprecated `add_timestamps` and `t.timestamps` without passing the `:null` + option. The default of `null: true` will change in Rails 5 to `null: false`. + ([Pull Request](https://github.com/rails/rails/pull/16481)) + +* 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 `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 depend 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)) + +### Notable changes + +* `SchemaDumper` uses `force: :cascade` on `create_table`. This makes it + possible to reload a schema when foreign keys are in place. + +* Added a `:required` option to singular associations, which defines a + presence validation on the association. + ([Pull Request](https://github.com/rails/rails/pull/16056)) + +* `ActiveRecord::Dirty` now detects in-place changes to mutable values. + Serialized attributes on Active Record models are no longer saved 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)) + +* Introduced the `db:purge` Rake task to empty the database for the + current environment. + ([Commit](https://github.com/rails/rails/commit/e2f232aba15937a4b9d14bd91e0392c6d55be58d)) + +* Introduced `ActiveRecord::Base#validate!` that raises + `ActiveRecord::RecordInvalid` if the record is invalid. + ([Pull Request](https://github.com/rails/rails/pull/8639)) + +* 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)) + +* The PostgreSQL adapter now supports the `jsonb` datatype in PostgreSQL 9.4+. + ([Pull Request](https://github.com/rails/rails/pull/16220)) + +* The 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)) + +* Added support for the `citext` column type in the PostgreSQL adapter. + ([Pull Request](https://github.com/rails/rails/pull/12523)) + +* Added support for user-created range types in the PostgreSQL adapter. + ([Commit](https://github.com/rails/rails/commit/4cb47167e747e8f9dc12b0ddaf82bdb68c03e032)) + +* `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 behavior was deprecated on Rails 4.1). + ([Pull Request](https://github.com/rails/rails/pull/14569)) + +* 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 `ActiveRecord::Base#pretty_print` to pretty print models. + ([Pull Request](https://github.com/rails/rails/pull/15172)) + +* `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)) + +* `ActiveRecord::Base#reflections` now returns a hash with string keys instead + of symbol keys. ([Pull Request](https://github.com/rails/rails/pull/17718)) + +* 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)) + +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 `validate` as an alias for `valid?`. + ([Pull Request](https://github.com/rails/rails/pull/14456)) + +* 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 disallows 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)) + +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 + +* Introduced a new configuration option `active_support.test_order` for + specifying the order test cases are executed. This option currently defaults + to `:sorted` but will be changed to `:random` in Rails 5.0. + ([Commit](https://github.com/rails/rails/commit/53e877f7d9291b2bf0b8c425f9e32ef35829f35b)) + +* `Object#try` and `Object#try!` can now be used without an explicit receiver in the block. + ([Commit](https://github.com/rails/rails/commit/5e51bdda59c9ba8e5faf86294e3e431bd45f1830), + [Pull Request](https://github.com/rails/rails/pull/17361)) + +* The `travel_to` test helper now truncates the `usec` component to 0. + ([Commit](https://github.com/rails/rails/commit/9f6e82ee4783e491c20f5244a613fdeb4024beb5)) + +* 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 in the block. + ([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)) + +* New [guide](constant_autoloading_and_reloading.html) about constant autoloading and reloading. + +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 |