Merge branch 'master' into bug/filtered_parameters_class

15 files changed, 398 insertions, 106 deletions

diff --git a/guides/bug_report_templates/action_controller_gem.rb b/guides/bug_report_templates/action_controller_gem.rb
index 46fabca3e8..1d059cc2a5 100644
--- a/guides/bug_report_templates/action_controller_gem.rb
+++ b/guides/bug_report_templates/action_controller_gem.rb
@@ -8,7 +8,7 @@ end
 gemfile(true) do
   source "https://rubygems.org"
   # Activate the gem you are reporting the issue against.
-  gem "rails", "5.1.0.rc1"
+  gem "rails", "5.1.0"
 end
 
 require "rack/test"
diff --git a/guides/bug_report_templates/active_job_gem.rb b/guides/bug_report_templates/active_job_gem.rb
index 71fe356ea0..252b270a0c 100644
--- a/guides/bug_report_templates/active_job_gem.rb
+++ b/guides/bug_report_templates/active_job_gem.rb
@@ -8,7 +8,7 @@ end
 gemfile(true) do
   source "https://rubygems.org"
   # Activate the gem you are reporting the issue against.
-  gem "activejob", "5.1.0.rc1"
+  gem "activejob", "5.1.0"
 end
 
 require "minitest/autorun"
diff --git a/guides/bug_report_templates/active_record_gem.rb b/guides/bug_report_templates/active_record_gem.rb
index a685c257ea..61d4e8d395 100644
--- a/guides/bug_report_templates/active_record_gem.rb
+++ b/guides/bug_report_templates/active_record_gem.rb
@@ -8,7 +8,7 @@ end
 gemfile(true) do
   source "https://rubygems.org"
   # Activate the gem you are reporting the issue against.
-  gem "activerecord", "5.1.0.rc1"
+  gem "activerecord", "5.1.0"
   gem "sqlite3"
 end
 
diff --git a/guides/bug_report_templates/active_record_migrations_gem.rb b/guides/bug_report_templates/active_record_migrations_gem.rb
index b4e822dfe0..0c398e334a 100644
--- a/guides/bug_report_templates/active_record_migrations_gem.rb
+++ b/guides/bug_report_templates/active_record_migrations_gem.rb
@@ -8,7 +8,7 @@ end
 gemfile(true) do
   source "https://rubygems.org"
   # Activate the gem you are reporting the issue against.
-  gem "activerecord", "5.1.0.rc1"
+  gem "activerecord", "5.1.0"
   gem "sqlite3"
 end
 
diff --git a/guides/bug_report_templates/generic_gem.rb b/guides/bug_report_templates/generic_gem.rb
index e1b705bea4..4dcd04ea27 100644
--- a/guides/bug_report_templates/generic_gem.rb
+++ b/guides/bug_report_templates/generic_gem.rb
@@ -8,7 +8,7 @@ end
 gemfile(true) do
   source "https://rubygems.org"
   # Activate the gem you are reporting the issue against.
-  gem "activesupport", "5.1.0.rc1"
+  gem "activesupport", "5.1.0"
 end
 
 require "active_support/core_ext/object/blank"
diff --git a/guides/rails_guides/generator.rb b/guides/rails_guides/generator.rb
index 28164a3cb4..35f014747c 100644
--- a/guides/rails_guides/generator.rb
+++ b/guides/rails_guides/generator.rb
@@ -73,7 +73,7 @@ module RailsGuides
 
         @output_dir  = "#{@guides_dir}/output"
         @output_dir += "/kindle"       if @kindle
-        @source_dir += "/#{@language}" if @language
+        @output_dir += "/#{@language}" if @language
       end
 
       def create_output_dir_if_needed
diff --git a/guides/rails_guides/helpers.rb b/guides/rails_guides/helpers.rb
index 6f4b0b492c..2a193ca6b5 100644
--- a/guides/rails_guides/helpers.rb
+++ b/guides/rails_guides/helpers.rb
@@ -15,7 +15,7 @@ module RailsGuides
     end
 
     def documents_by_section
-      @documents_by_section ||= YAML.load_file(File.expand_path("../../source/#{@lang ? @lang + '/' : ''}documents.yaml", __FILE__))
+      @documents_by_section ||= YAML.load_file(File.expand_path("../../source/#{@language ? @language + '/' : ''}documents.yaml", __FILE__))
     end
 
     def documents_flat
diff --git a/guides/rails_guides/markdown/renderer.rb b/guides/rails_guides/markdown/renderer.rb
index 9d43c10be6..7ac3d417a4 100644
--- a/guides/rails_guides/markdown/renderer.rb
+++ b/guides/rails_guides/markdown/renderer.rb
@@ -93,7 +93,7 @@ HTML
         def github_file_url(file_path)
           tree = version || edge
 
-          root = file_path[%r{(.+)/}, 1]
+          root = file_path[%r{(\w+)/}, 1]
           path = \
             case root
             when "abstract_controller", "action_controller", "action_dispatch"
diff --git a/guides/source/5_1_release_notes.md b/guides/source/5_1_release_notes.md
index ffa18f1a2b..fa92b9e5f8 100644
--- a/guides/source/5_1_release_notes.md
+++ b/guides/source/5_1_release_notes.md
@@ -40,7 +40,7 @@ Major Features
 
 [Pull Request](https://github.com/rails/rails/pull/26836)
 
-Rails 5.1 will allow managing JavaScript dependencies
+Rails 5.1 allows managing JavaScript dependencies
 from NPM via Yarn. This will make it easy to use libraries like React, VueJS
 or any other library from NPM world. The Yarn support is integrated with
 the asset pipeline so that all dependencies will work seamlessly with the
@@ -70,14 +70,14 @@ offerings. It is no longer required, as the UJS has been rewritten to use plain,
 vanilla JavaScript. This code now ships inside of Action View as
 `rails-ujs`.
 
-You can still use the jQuery version if needed, but it is no longer required by default.
+You can still use jQuery if needed, but it is no longer required by default.
 
 ### System tests
 
 [Pull Request](https://github.com/rails/rails/pull/26703)
 
 Rails 5.1 has baked-in support for writing Capybara tests, in the form of
-System tests. You need no longer worry about configuring Capybara and
+System tests. You no longer need to worry about configuring Capybara and
 database cleaning strategies for such tests. Rails 5.1 provides a wrapper
 for running tests in Chrome with additional features such as failure
 screenshots.
@@ -86,8 +86,8 @@ screenshots.
 
 [Pull Request](https://github.com/rails/rails/pull/28038)
 
-Rails will now allow management of application secrets in a secure way,
-building on top of the [sekrets](https://github.com/ahoward/sekrets) gem.
+Rails now allows management of application secrets in a secure way,
+inspired by the [sekrets](https://github.com/ahoward/sekrets) gem.
 
 Run `bin/rails secrets:setup` to setup a new encrypted secrets file. This will
 also generate a master key, which must be stored outside of the repository. The
@@ -106,33 +106,24 @@ order to share instance variables, headers and other common setup.
 
 ``` ruby
 class InvitationsMailer < ApplicationMailer
-
   before_action { @inviter, @invitee = params[:inviter], params[:invitee] }
   before_action { @account = params[:inviter].account }
 
   def account_invitation
     mail subject: "#{@inviter.name} invited you to their Basecamp (#{@account.name})"
   end
-
-  def project_invitation
-    @project    = params[:project]
-    @summarizer = ProjectInvitationSummarizer.new(@project.bucket)
-
-    mail subject: "#{@inviter.name.familiar} added you to a project in Basecamp (#{@account.name})"
-  end
 end
 
-InvitationsMailer.with(inviter: person_a, invitee: person_b).account_invitation.deliver_later
+InvitationsMailer.with(inviter: person_a, invitee: person_b)
+                 .account_invitation.deliver_later
 ```
 
 ### Direct & resolved routes
 
 [Pull Request](https://github.com/rails/rails/pull/23138)
 
-Rails 5.1 has added two new methods, `resolve` and `direct`, to the routing
-DSL.
-
-The `resolve` method allows customizing polymorphic mapping of models.
+Rails 5.1 adds two new methods, `resolve` and `direct`, to the routing
+DSL. The `resolve` method allows customizing polymorphic mapping of models.
 
 ``` ruby
 resource :basket
@@ -181,50 +172,94 @@ Before Rails 5.1, there were two interfaces for handling HTML forms:
 Rails 5.1 combines both of these interfaces with `form_with`, and
 can generate form tags based on URLs, scopes or models.
 
-``` erb
-# Using just a URL:
+Using just a URL:
 
+``` erb
 <%= form_with url: posts_path do |form| %>
   <%= form.text_field :title %>
 <% end %>
 
-# =>
+<%# Will generate %>
+
 <form action="/posts" method="post" data-remote="true">
   <input type="text" name="title">
 </form>
+```
 
-# Adding a scope prefixes the input field names:
+Adding a scope prefixes the input field names:
 
+``` erb
 <%= form_with scope: :post, url: posts_path do |form| %>
   <%= form.text_field :title %>
 <% end %>
-# =>
+
+<%# Will generate %>
+
 <form action="/posts" method="post" data-remote="true">
   <input type="text" name="post[title]">
 </form>
+```
 
-# Using a model infers both the URL and scope:
+Using a model infers both the URL and scope:
 
+``` erb
 <%= form_with model: Post.new do |form| %>
   <%= form.text_field :title %>
 <% end %>
-# =>
+
+<%# Will generate %>
+
 <form action="/posts" method="post" data-remote="true">
   <input type="text" name="post[title]">
 </form>
+```
 
-# An existing model makes an update form and fills out field values:
+An existing model makes an update form and fills out field values:
 
+``` erb
 <%= form_with model: Post.first do |form| %>
   <%= form.text_field :title %>
 <% end %>
-# =>
+
+<%# Will generate %>
+
 <form action="/posts/1" method="post" data-remote="true">
   <input type="hidden" name="_method" value="patch">
   <input type="text" name="post[title]" value="<the title of the post>">
 </form>
 ```
 
+Incompatibilities
+-----------------
+
+The following changes may require immediate action upon upgrade.
+
+### Transactional tests with multiple connections
+
+Transactional tests now wrap all Active Record connections in database
+transactions.
+
+When a test spawns additional threads, and those threads obtain database
+connections, those connections are now handled specially:
+
+The threads will share a single connection, which is inside the managed
+transaction. This ensures all threads see the database in the same
+state, ignoring the outermost transaction. Previously, such additional
+connections were unable to see the fixture rows, for example.
+
+When a thread enters a nested transaction, it will temporarily obtain
+exclusive use of the connection, to maintain isolation.
+
+If your tests currently rely on obtaining a separate,
+outside-of-transaction, connection in a spawned thread, you'll need to
+switch to more explicit connection management.
+
+If your tests spawn threads and those threads interact while also using
+explicit database transactions, this change may introduce a deadlock.
+
+The easy way to opt out of this new behavior is to disable transactional
+tests on any test cases it affects.
+
 Railties
 --------
 
@@ -233,7 +268,7 @@ Please refer to the [Changelog][railties] for detailed changes.
 ### Removals
 
 *   Remove deprecated `config.static_cache_control`.
-    ([commit](https://github.com/rails/rails/commit/c861decd44198f8d7d774ee6a74194d1ac1a5a13)
+    ([commit](https://github.com/rails/rails/commit/c861decd44198f8d7d774ee6a74194d1ac1a5a13))
 
 *   Remove deprecated `config.serve_static_files`.
     ([commit](https://github.com/rails/rails/commit/0129ca2eeb6d5b2ea8c6e6be38eeb770fe45f1fa))
@@ -267,7 +302,7 @@ Please refer to the [Changelog][railties] for detailed changes.
 *   Add Yarn support in new apps with a yarn binstub and package.json.
     ([Pull Request](https://github.com/rails/rails/pull/26836))
 
-*   Add Webpack support in new apps via the --webpack option, which will delegate
+*   Add Webpack support in new apps via the `--webpack` option, which will delegate
     to the rails/webpacker gem.
     ([Pull Request](https://github.com/rails/rails/pull/27288))
 
@@ -278,6 +313,9 @@ Please refer to the [Changelog][railties] for detailed changes.
 *   Add encrypted secrets in `config/secrets.yml.enc`.
     ([Pull Request](https://github.com/rails/rails/pull/28038))
 
+*   Display railtie class name in `rails initializers`.
+    ([Pull Request](https://github.com/rails/rails/pull/25257))
+
 Action Cable
 -----------
 
@@ -290,10 +328,7 @@ Please refer to the [Changelog][action-cable] for detailed changes.
     with multiple applications.
     ([Pull Request](https://github.com/rails/rails/pull/27425))
 
-*   Permit same-origin connections by default.
-    ([commit](https://github.com/rails/rails/commit/dae404473409fcab0e07976aec626df670e52282))
-
-*   Add `ActiveSupport::Notifications` hook for broadcasing data.
+*   Add `ActiveSupport::Notifications` hook for broadcasting data.
     ([Pull Request](https://github.com/rails/rails/pull/24988))
 
 Action Pack
@@ -303,10 +338,34 @@ Please refer to the [Changelog][action-pack] for detailed changes.
 
 ### Removals
 
+*   Removed support for non-keyword arguments in `#process`, `#get`, `#post`,
+    `#patch`, `#put`, `#delete`, and `#head` for the `ActionDispatch::IntegrationTest`
+    and `ActionController::TestCase` classes.
+    ([Commit](https://github.com/rails/rails/commit/98b8309569a326910a723f521911e54994b112fb),
+    [Commit](https://github.com/rails/rails/commit/de9542acd56f60d281465a59eac11e15ca8b3323))
+
+*   Removed deprecated `ActionDispatch::Callbacks.to_prepare` and
+    `ActionDispatch::Callbacks.to_cleanup`.
+    ([Commit](https://github.com/rails/rails/commit/3f2b7d60a52ffb2ad2d4fcf889c06b631db1946b))
+
+*   Removed deprecated methods related to controller filters.
+    ([Commit](https://github.com/rails/rails/commit/d7be30e8babf5e37a891522869e7b0191b79b757))
+
 ### Deprecations
 
+*   Deprecated `config.action_controller.raise_on_unfiltered_parameters`.
+    It doesn't have any effect in Rails 5.1.
+    ([Commit](https://github.com/rails/rails/commit/c6640fb62b10db26004a998d2ece98baede509e5))
+
 ### Notable changes
 
+*   Added the `direct` and `resolve` methods to the routing DSL.
+    ([Pull Request](https://github.com/rails/rails/pull/23138))
+
+*   Added a new `ActionDispatch::SystemTestCase` class to write system tests in
+    your applications.
+    ([Pull Request](https://github.com/rails/rails/pull/26703))
+
 Action View
 -------------
 
@@ -341,6 +400,9 @@ Please refer to the [Changelog][action-view] for detailed changes.
 *   Add `form_with` to unify `form_tag` and `form_for` usage.
     ([Pull Request](https://github.com/rails/rails/pull/26976))
 
+*   Add `check_parameters` option to `current_page?`.
+    ([Pull Request](https://github.com/rails/rails/pull/27549))
+
 Action Mailer
 -------------
 
@@ -348,10 +410,6 @@ Please refer to the [Changelog][action-mailer] for detailed changes.
 
 ### Notable changes
 
-*   Exception handling: use `rescue_from` to handle exceptions raised by
-    mailer actions, by message delivery, and by deferred delivery jobs.
-    ([commit](https://github.com/rails/rails/commit/e35b98e6f5c54330245645f2ed40d56c74538902))
-
 *   Allowed setting custom content type when attachments are included
     and body is set inline.
     ([Pull Request](https://github.com/rails/rails/pull/27227))
@@ -374,10 +432,88 @@ Please refer to the [Changelog][active-record] for detailed changes.
 
 ### Removals
 
+*   Removed support for passing arguments and block at the same time to
+    `ActiveRecord::QueryMethods#select`.
+    ([Commit](https://github.com/rails/rails/commit/4fc3366d9d99a0eb19e45ad2bf38534efbf8c8ce))
+
+*   Removed deprecated `activerecord.errors.messages.restrict_dependent_destroy.one` and
+    `activerecord.errors.messages.restrict_dependent_destroy.many` i18n scopes.
+    ([Commit](https://github.com/rails/rails/commit/00e3973a311))
+
+*   Removed deprecated force reload argument in singular and collection association readers.
+    ([Commit](https://github.com/rails/rails/commit/09cac8c67af))
+
+*   Removed deprecated support for passing a column to `#quote`.
+    ([Commit](https://github.com/rails/rails/commit/e646bad5b7c))
+
+*   Removed deprecated `name` arguments from `#tables`.
+    ([Commit](https://github.com/rails/rails/commit/d5be101dd02214468a27b6839ffe338cfe8ef5f3))
+
+*   Removed deprecated behavior of `#tables` and `#table_exists?` to return tables and views
+    to return only tables and not views.
+    ([Commit](https://github.com/rails/rails/commit/5973a984c369a63720c2ac18b71012b8347479a8))
+
+*   Removed deprecated `original_exception` argument in `ActiveRecord::StatementInvalid#initialize`
+    and `ActiveRecord::StatementInvalid#original_exception`.
+    ([Commit](https://github.com/rails/rails/commit/bc6c5df4699d3f6b4a61dd12328f9e0f1bd6cf46))
+
+*   Removed deprecated support of passing a class as a value in a query.
+    ([Commit](https://github.com/rails/rails/commit/b4664864c972463c7437ad983832d2582186e886))
+
+*   Removed deprecated support to query using commas on LIMIT.
+    ([Commit](https://github.com/rails/rails/commit/fc3e67964753fb5166ccbd2030d7382e1976f393))
+
+*   Removed deprecated `conditions` parameter from `#destroy_all`.
+    ([Commit](https://github.com/rails/rails/commit/d31a6d1384cd740c8518d0bf695b550d2a3a4e9b))
+
+*   Removed deprecated `conditions` parameter from `#delete_all`.
+    ([Commit](https://github.com/rails/rails/pull/27503/commits/e7381d289e4f8751dcec9553dcb4d32153bd922b))
+
+*   Removed deprecated method `#load_schema_for` in favor of `#load_schema`.
+    ([Commit](https://github.com/rails/rails/commit/419e06b56c3b0229f0c72d3e4cdf59d34d8e5545))
+
+*   Removed deprecated `#raise_in_transactional_callbacks` configuration.
+    ([Commit](https://github.com/rails/rails/commit/8029f779b8a1dd9848fee0b7967c2e0849bf6e07))
+
+*   Removed deprecated `#use_transactional_fixtures` configuration.
+    ([Commit](https://github.com/rails/rails/commit/3955218dc163f61c932ee80af525e7cd440514b3))
+
 ### Deprecations
 
+*   Deprecated `error_on_ignored_order_or_limit` flag in favor of
+    `error_on_ignored_order`.
+    ([Commit](https://github.com/rails/rails/commit/451437c6f57e66cc7586ec966e530493927098c7))
+
+*   Deprecated `sanitize_conditions` in favor of `sanitize_sql`.
+    ([Pull Request](https://github.com/rails/rails/pull/25999))
+
+*   Deprecated `supports_migrations?` on connection adapters.
+    ([Pull Request](https://github.com/rails/rails/pull/28172))
+
+*   Deprecated `Migrator.schema_migrations_table_name`, use `SchemaMigration.table_name` instead.
+    ([Pull Request](https://github.com/rails/rails/pull/28351))
+
+*   Deprecated using `#quoted_id` in quoting and type casting.
+    ([Pull Request](https://github.com/rails/rails/pull/27962))
+
+*   Deprecated passing `default` argument to `#index_name_exists?`.
+    ([Pull Request](https://github.com/rails/rails/pull/26930))
+
 ### Notable changes
 
+*   Change Default Primary Keys to BIGINT.
+    ([Pull Request](https://github.com/rails/rails/pull/26266))
+
+*   Virtual/generated column support for MySQL 5.7.5+ and MariaDB 5.2.0+.
+    ([Commit](https://github.com/rails/rails/commit/65bf1c60053e727835e06392d27a2fb49665484c))
+
+*   Added support for limits in batch processing.
+    ([Commit](https://github.com/rails/rails/commit/451437c6f57e66cc7586ec966e530493927098c7))
+
+*   Transactional tests now wrap all Active Record connections in database
+    transactions.
+    ([Pull Request](https://github.com/rails/rails/pull/28726))
+
 *   Skipped comments in the output of `mysqldump` command by default.
     ([Pull Request](https://github.com/rails/rails/pull/23301))
 
@@ -389,6 +525,16 @@ Please refer to the [Changelog][active-record] for detailed changes.
 *   Pass `"-v ON_ERROR_STOP=1"` flag with `psql` command to not suppress SQL errors.
     ([Pull Request](https://github.com/rails/rails/pull/24773))
 
+*   Add `ActiveRecord::Base.connection_pool.stat`.
+    ([Pull Request](https://github.com/rails/rails/pull/26988))
+
+*   Inheriting directly from `ActiveRecord::Migration` raises an error.
+    Specify the Rails version for which the migration was written for.
+    ([Commit](https://github.com/rails/rails/commit/249f71a22ab21c03915da5606a063d321f04d4d3))
+
+*   An error is raised when `through` association has ambiguous reflection name.
+    ([Commit](https://github.com/rails/rails/commit/0944182ad7ed70d99b078b22426cbf844edd3f61))
+
 Active Model
 ------------
 
@@ -440,10 +586,36 @@ Please refer to the [Changelog][active-support] for detailed changes.
 
 ### Removals
 
+*   Removed the `ActiveSupport::Concurrency::Latch` class.
+    ([Commit](https://github.com/rails/rails/commit/0d7bd2031b4054fbdeab0a00dd58b1b08fb7fea6))
+
+*   Removed `halt_callback_chains_on_return_false`.
+    ([Commit](https://github.com/rails/rails/commit/4e63ce53fc25c3bc15c5ebf54bab54fa847ee02a))
+
+*   Removed deprecated behavior that halts callbacks when the return is false.
+    ([Commit](https://github.com/rails/rails/commit/3a25cdca3e0d29ee2040931d0cb6c275d612dffe))
+
 ### Deprecations
 
+*   The top level `HashWithIndifferentAccess` class has been softly deprecated
+    in favor of the `ActiveSupport::HashWithIndifferentAccess` one.
+    ([Pull Request](https://github.com/rails/rails/pull/28157))
+
+*   Deprecated passing string to `:if` and `:unless` conditional options on `set_callback` and `skip_callback`.
+    ([Commit](https://github.com/rails/rails/commit/0952552)
+
 ### Notable changes
 
+*   Fixed duration parsing and traveling to make it consistent across DST changes.
+    ([Commit](https://github.com/rails/rails/commit/8931916f4a1c1d8e70c06063ba63928c5c7eab1e),
+    [Pull Request](https://github.com/rails/rails/pull/26597))
+
+*   Updated Unicode to version 9.0.0.
+    ([Pull Request](https://github.com/rails/rails/pull/27822))
+
+*   Add Duration#before and #after as aliases for #ago and #since.
+    ([Pull Request](https://github.com/rails/rails/pull/27721))
+
 *   Added `Module#delegate_missing_to` to delegate method calls not
     defined for the current object to a proxy object.
     ([Pull Request](https://github.com/rails/rails/pull/23930))
@@ -452,6 +624,15 @@ Please refer to the [Changelog][active-support] for detailed changes.
     of the current date & time.
     ([Pull Request](https://github.com/rails/rails/pull/24930))
 
+*   Introduced the `assert_changes` and `assert_no_changes` methods for tests.
+    ([Pull Request](https://github.com/rails/rails/pull/25393))
+
+*   The `travel` and `travel_to` methods now raise on nested calls.
+    ([Pull Request](https://github.com/rails/rails/pull/24890))
+
+*   Update `DateTime#change` to support usec and nsec.
+    ([Pull Request](https://github.com/rails/rails/pull/28242))
+
 Credits
 -------
 
diff --git a/guides/source/autoloading_and_reloading_constants.md b/guides/source/autoloading_and_reloading_constants.md
index 61657023e7..05743ee4ce 100644
--- a/guides/source/autoloading_and_reloading_constants.md
+++ b/guides/source/autoloading_and_reloading_constants.md
@@ -983,20 +983,19 @@ WHERE "polygons"."type" IN ("Rectangle")
 That is not a bug, the query includes all *known* descendants of `Rectangle`.
 
 A way to ensure this works correctly regardless of the order of execution is to
-load the leaves of the tree by hand at the bottom of the file that defines the
-root class:
+manually load the direct subclasses at the bottom of the file that defines each
+intermediate class:
 
 ```ruby
-# app/models/polygon.rb
-class Polygon < ApplicationRecord
+# app/models/rectangle.rb
+class Rectangle < Polygon
 end
-require_dependency ‘square’
+require_dependency 'square'
 ```
 
-Only the leaves that are **at least grandchildren** need to be loaded this
-way. Direct subclasses do not need to be preloaded. If the hierarchy is
-deeper, intermediate classes will be autoloaded recursively from the bottom
-because their constant will appear in the class definitions as superclass.
+This needs to happen for every intermediate (non-root and non-leaf) class. The
+root class does not scope the query by type, and therefore does not necessarily
+have to know all its descendants.
 
 ### Autoloading and `require`
 
diff --git a/guides/source/contributing_to_ruby_on_rails.md b/guides/source/contributing_to_ruby_on_rails.md
index 39f4272b3c..2f2962a3e6 100644
--- a/guides/source/contributing_to_ruby_on_rails.md
+++ b/guides/source/contributing_to_ruby_on_rails.md
@@ -141,14 +141,15 @@ NOTE: To help our CI servers you should add [ci skip] to your documentation comm
 Translating Rails Guides
 ------------------------
 
-We are happy to have people volunteer to translate the Rails guides into their own language.
-If you want to translate the Rails guides in your own language, follows these steps:
+We are happy to have people volunteer to translate the Rails guides. Just follow these steps:
 
-* Fork the project (rails/rails).
+* Fork https://github.com/rails/rails.
 * Add a source folder for your own language, for example: *guides/source/it-IT* for Italian.
 * Copy the contents of *guides/source* into your own language directory and translate them.
 * Do NOT translate the HTML files, as they are automatically generated.
 
+Note that translations are not submitted to the Rails repository. As detailed above, your work happens in a fork. This is so because in practice documentation maintenance via patches is only sustainable in English.
+
 To generate the guides in HTML format cd into the *guides* directory then run (eg. for it-IT):
 
 ```bash
diff --git a/guides/source/documents.yaml b/guides/source/documents.yaml
index 5fccdcccec..2afef57fc2 100644
--- a/guides/source/documents.yaml
+++ b/guides/source/documents.yaml
@@ -197,7 +197,6 @@
       name: Ruby on Rails 5.1 Release Notes
       url: 5_1_release_notes.html
       description: Release notes for Rails 5.1.
-      work_in_progress: true
     -
       name: Ruby on Rails 5.0 Release Notes
       url: 5_0_release_notes.html
diff --git a/guides/source/testing.md b/guides/source/testing.md
index 7741834153..c0394f927e 100644
--- a/guides/source/testing.md
+++ b/guides/source/testing.md
@@ -350,7 +350,7 @@ Rails adds some custom assertions of its own to the `minitest` framework:
 | --------------------------------------------------------------------------------- | ------- |
 | [`assert_difference(expressions, difference = 1, message = nil) {...}`](http://api.rubyonrails.org/classes/ActiveSupport/Testing/Assertions.html#method-i-assert_difference) | Test numeric difference between the return value of an expression as a result of what is evaluated in the yielded block.|
 | [`assert_no_difference(expressions, message = nil, &block)`](http://api.rubyonrails.org/classes/ActiveSupport/Testing/Assertions.html#method-i-assert_no_difference) | Asserts that the numeric result of evaluating an expression is not changed before and after invoking the passed in block.|
-| [`assert_nothing_raised { block }`](http://api.rubyonrails.org/classes/ActiveSupport/TestCase.html#method-i-assert_nothing_raised) | Ensures that the given block doesn't raise any exceptions.|
+| [`assert_nothing_raised { block }`](http://api.rubyonrails.org/classes/ActiveSupport/Testing/Assertions.html#method-i-assert_nothing_raised) | Ensures that the given block doesn't raise any exceptions.|
 | [`assert_recognizes(expected_options, path, extras={}, message=nil)`](http://api.rubyonrails.org/classes/ActionDispatch/Assertions/RoutingAssertions.html#method-i-assert_recognizes) | Asserts that the routing of the given path was handled correctly and that the parsed options (given in the expected_options hash) match path. Basically, it asserts that Rails recognizes the route given by expected_options.|
 | [`assert_generates(expected_path, options, defaults={}, extras = {}, message=nil)`](http://api.rubyonrails.org/classes/ActionDispatch/Assertions/RoutingAssertions.html#method-i-assert_generates) | Asserts that the provided options can be used to generate the provided path. This is the inverse of assert_recognizes. The extras parameter is used to tell the request the names and values of additional request parameters that would be in a query string. The message parameter allows you to specify a custom error message for assertion failures.|
 | [`assert_response(type, message = nil)`](http://api.rubyonrails.org/classes/ActionDispatch/Assertions/ResponseAssertions.html#method-i-assert_response) | Asserts that the response comes with a specific status code. You can specify `:success` to indicate 200-299, `:redirect` to indicate 300-399, `:missing` to indicate 404, or `:error` to match the 500-599 range. You can also pass an explicit status number or its symbolic equivalent. For more information, see [full list of status codes](http://rubydoc.info/github/rack/rack/master/Rack/Utils#HTTP_STATUS_CODES-constant) and how their [mapping](http://rubydoc.info/github/rack/rack/master/Rack/Utils#SYMBOL_TO_STATUS_CODE-constant) works.|
@@ -610,9 +610,9 @@ For creating Rails system tests, you use the `test/system` directory in your
 application. Rails provides a generator to create a system test skeleton for you.
 
 ```bash
-$ bin/rails generate system_test users_create
+$ bin/rails generate system_test users
       invoke test_unit
-      create test/system/users_creates_test.rb
+      create test/system/users_test.rb
 ```
 
 Here's what a freshly-generated system test looks like:
@@ -620,11 +620,11 @@ Here's what a freshly-generated system test looks like:
 ```ruby
 require "application_system_test_case"
 
-class UsersCreatesTest < ApplicationSystemTestCase
+class UsersTest < ApplicationSystemTestCase
   # test "visiting the index" do
-  #   visit users_creates_url
+  #   visit users_url
   #
-  #   assert_selector "h1", text: "UsersCreate"
+  #   assert_selector "h1", text: "Users"
   # end
 end
 ```
@@ -658,8 +658,8 @@ end
 
 The driver name is a required argument for `driven_by`. The optional arguments
 that can be passed to `driven_by` are `:using` for the browser (this will only
-be used for non-headless drivers like Selenium), and `:screen_size` to change
-the size of the screen for screenshots.
+be used by Selenium), and `:screen_size` to change the size of the screen for
+screenshots.
 
 ```ruby
 require "test_helper"
@@ -1406,7 +1406,7 @@ In order to test that your mailer is working as expected, you can use unit tests
 
 For the purposes of unit testing a mailer, fixtures are used to provide an example of how the output _should_ look. Because these are example emails, and not Active Record data like the other fixtures, they are kept in their own subdirectory apart from the other fixtures. The name of the directory within `test/fixtures` directly corresponds to the name of the mailer. So, for a mailer named `UserMailer`, the fixtures should reside in `test/fixtures/user_mailer` directory.
 
-When you generated your mailer, the generator creates stub fixtures for each of the mailers actions. If you didn't use the generator, you'll have to create those files yourself.
+If you generated your mailer, the generator does not create stub fixtures for the mailers actions. You'll have to create those files yourself as described above.
 
 #### The Basic Test Case
 
@@ -1482,7 +1482,7 @@ class UserControllerTest < ActionDispatch::IntegrationTest
 
     assert_equal "You have been invited by me@example.com", invite_email.subject
     assert_equal 'friend@example.com', invite_email.to[0]
-    assert_match(/Hi friend@example.com/, invite_email.body.to_s)
+    assert_match(/Hi friend@example\.com/, invite_email.body.to_s)
   end
 end
 ```
diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md
index ff747a95a0..93864db141 100644
--- a/guides/source/upgrading_ruby_on_rails.md
+++ b/guides/source/upgrading_ruby_on_rails.md
@@ -83,7 +83,7 @@ Also, if you have pretty old YAML documents containing dumps of such objects,
 you may need to load and dump them again to make sure that they reference
 the right constant, and that loading them won't break in the future.
 
-### `config.secrets` now loaded with all keys as symbols
+### `application.secrets` now loaded with all keys as symbols
 
 If your application stores nested configuration in `config/secrets.yml`, all keys
 are now loaded as symbols, so access using strings should be changed.
@@ -91,13 +91,13 @@ are now loaded as symbols, so access using strings should be changed.
 From:
 
 ```ruby
-Rails.appplication.config.secrets[:smtp_settings]["address"]
+Rails.application.secrets[:smtp_settings]["address"]
 ```
 
 To:
 
 ```ruby
-Rails.application.config.secrets[:smtp_settings][:address]
+Rails.application.secrets[:smtp_settings][:address]
 ```
 
 Upgrading from Rails 4.2 to Rails 5.0
diff --git a/guides/source/working_with_javascript_in_rails.md b/guides/source/working_with_javascript_in_rails.md
index 2a6a87c232..cf08c5dd1d 100644
--- a/guides/source/working_with_javascript_in_rails.md
+++ b/guides/source/working_with_javascript_in_rails.md
@@ -141,6 +141,8 @@ follow this pattern.
 Built-in Helpers
 ----------------------
 
+### Remote elements
+
 Rails provides a bunch of view helper methods written in Ruby to assist you
 in generating HTML. Sometimes, you want to add a little Ajax to those elements,
 and Rails has got your back in those cases.
@@ -153,14 +155,18 @@ Unless you have disabled the Asset Pipeline,
 provides the JavaScript half, and the regular Ruby view helpers add appropriate
 tags to your DOM.
 
-### form_for
+You can read below about the different events that are fired dealing with
+remote elements inside your application.
+
+#### form_with
 
-[`form_for`](http://api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html#method-i-form_for)
-is a helper that assists with writing forms. `form_for` takes a `:remote`
-option. It works like this:
+[`form_with`](http://api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html#method-i-form_with)
+is a helper that assists with writing forms. By default, `form_with` assumes that
+your form will be using Ajax. You can opt out of this behavior by
+passing the `:local` option `form_with`.
 
 ```erb
-<%= form_for(@article, remote: true) do |f| %>
+<%= form_with(model: @article) do |f| %>
   ...
 <% end %>
 ```
@@ -168,7 +174,7 @@ option. It works like this:
 This will generate the following HTML:
 
 ```html
-<form accept-charset="UTF-8" action="/articles" class="new_article" data-remote="true" id="new_article" method="post">
+<form action="/articles" method="post" data-remote="true">
   ...
 </form>
 ```
@@ -189,32 +195,9 @@ $(document).ready ->
 ```
 
 Obviously, you'll want to be a bit more sophisticated than that, but it's a
-start. You can see more about the events [in the jquery-ujs wiki](https://github.com/rails/jquery-ujs/wiki/ajax).
-
-### form_tag
-
-[`form_tag`](http://api.rubyonrails.org/classes/ActionView/Helpers/FormTagHelper.html#method-i-form_tag)
-is very similar to `form_for`. It has a `:remote` option that you can use like
-this:
-
-```erb
-<%= form_tag('/articles', remote: true) do %>
-  ...
-<% end %>
-```
-
-This will generate the following HTML:
-
-```html
-<form accept-charset="UTF-8" action="/articles" data-remote="true" method="post">
-  ...
-</form>
-```
-
-Everything else is the same as `form_for`. See its documentation for full
-details.
+start.
 
-### link_to
+#### link_to
 
 [`link_to`](http://api.rubyonrails.org/classes/ActionView/Helpers/UrlHelper.html#method-i-link_to)
 is a helper that assists with generating links. It has a `:remote` option you
@@ -230,7 +213,7 @@ which generates
 <a href="/articles/1" data-remote="true">an article</a>
 ```
 
-You can bind to the same Ajax events as `form_for`. Here's an example. Let's
+You can bind to the same Ajax events as `form_with`. Here's an example. Let's
 assume that we have a list of articles that can be deleted with just one
 click. We would generate some HTML like this:
 
@@ -246,7 +229,7 @@ $ ->
     alert "The article was deleted."
 ```
 
-### button_to
+#### button_to
 
 [`button_to`](http://api.rubyonrails.org/classes/ActionView/Helpers/UrlHelper.html#method-i-button_to) is a helper that helps you create buttons. It has a `:remote` option that you can call like this:
 
@@ -262,7 +245,136 @@ this generates
 </form>
 ```
 
-Since it's just a `<form>`, all of the information on `form_for` also applies.
+Since it's just a `<form>`, all of the information on `form_with` also applies.
+
+### Customize remote elements
+
+It is possible to customize the behavior of elements with a `data-remote`
+attribute without writing a line of JavaScript. Your can specify extra `data-`
+attributes to accomplish this.
+
+#### `data-method`
+
+Activating hyperlinks always results in an HTTP GET request. However, if your
+application is [RESTful](http://en.wikipedia.org/wiki/Representational_State_Transfer),
+some links are in fact actions that change data on the server, and must be
+performed with non-GET requests. This attribute allows marking up such links
+with an explicit method such as "post", "put" or "delete".
+
+The way it works is that, when the link is activated, it constructs a hidden form
+in the document with the "action" attribute corresponding to "href" value of the
+link, and the method corresponding to `data-method` value, and submits that form.
+
+NOTE: Because submitting forms with HTTP methods other than GET and POST isn't
+widely supported across browsers, all other HTTP methods are actually sent over
+POST with the intended method indicated in the `_method` parameter. Rails
+automatically detects and compensates for this.
+
+#### `data-url` and `data-params`
+
+Certain elements of your page aren't actually referring to any URL, but you may want
+them to trigger Ajax calls. Specifying the `data-url` attribute along with
+the `data-remote` one will trigger an Ajax call to the given URL. You can also
+specify extra parameters through the `data-params` attribute.
+
+This can be useful to trigger an action on check-boxes for instance:
+
+```html
+<input type="checkbox" data-remote="true"
+    data-url="/update" data-params="id=10" data-method="put">
+```
+
+#### `data-type`
+
+It is also possible to define the Ajax `dataType` explicitly while performing
+requests for `data-remote` elements, by way of the `data-type` attribute.
+
+### Confirmations
+
+You can ask for an extra confirmation of the user by adding a `data-confirm`
+attribute on links and forms. The user will be presented a JavaScript `confirm()`
+dialog containing the attribute's text. If the user chooses to cancel, the action
+doesn't take place.
+
+Adding this attribute on links will trigger the dialog on click, and adding it
+on forms will trigger it on submit. For example:
+
+```erb
+<%= link_to "Dangerous zone", dangerous_zone_path,
+  data: { confirm: 'Are you sure?' } %>
+```
+
+This generates:
+
+```html
+<a href="..." data-confirm="Are you sure?">Dangerous zone</a>
+```
+
+The attribute is also allowed on form submit buttons. This allows you to customize
+the warning message depending on the button which was activated. In this case,
+you should **not** have `data-confirm` on the form itself.
+
+The default confirmation uses a JavaScript confirm dialog, but you can customize
+this by listening to the `confirm` event, which is fired just before the confirmation
+window appears to the user. To cancel this default confirmation, have the confirm
+handler to return `false`.
+
+### Automatic disabling
+
+It is also possible to automatically disable an input while the form is submitting
+by using the `data-disable-with` attribute. This is to prevent accidental
+double-clicks from the user, which could result in duplicate HTTP requests that
+the backend may not detect as such. The value of the attribute is the text that will
+become the new value of the button in its disabled state.
+
+This also works for links with `data-method` attribute.
+
+For example:
+
+```erb
+<%= form_with(model: @article.new) do |f| %>
+  <%= f.submit data: { "disable-with": "Saving..." } %>
+<%= end %>
+```
+
+This generates a form with:
+
+```html
+<input data-disable-with="Saving..." type="submit">
+```
+
+Dealing with Ajax events
+------------------------
+
+Here are the different events that are fired when you deal with elements
+that have a `data-remote` attribute:
+
+NOTE: All handlers bound to these events are always passed the event object as the
+first argument. The table below describes the extra parameters passed after the
+event argument. For example, if the extra parameters are listed as `xhr, settings`,
+then to access them, you would define your handler with `function(event, xhr, settings)`.
+
+| Event name          | Extra parameters | Fired                                                       |
+|---------------------|------------------|-------------------------------------------------------------|
+| `ajax:before`       |                  | Before the whole ajax business, aborts if stopped.          |
+| `ajax:beforeSend`   | xhr, options     | Before the request is sent, aborts if stopped.              |
+| `ajax:send`         | xhr              | When the request is sent.                                   |
+| `ajax:success`      | xhr, status, err | After completion, if the response was a success.            |
+| `ajax:error`        | xhr, status, err | After completion, if the response was an error.             |
+| `ajax:complete`     | xhr, status      | After the request has been completed, no matter the outcome.|
+| `ajax:aborted:file` | elements         | If there are non-blank file inputs, aborts if stopped.      |
+
+### Stoppable events
+
+If you stop `ajax:before` or `ajax:beforeSend` by returning false from the
+handler method, the Ajax request will never take place. The `ajax:before` event
+is also useful for manipulating form data before serialization. The
+`ajax:beforeSend` event is also useful for adding custom request headers.
+
+If you stop the `ajax:aborted:file` event, the default behavior of allowing the
+browser to submit the form via normal means (i.e. non-AJAX submission) will be
+canceled and the form will not be submitted at all. This is useful for
+implementing your own AJAX file upload workaround.
 
 Server-Side Concerns
 --------------------
@@ -297,7 +409,7 @@ The index view (`app/views/users/index.html.erb`) contains:
 
 <br>
 
-<%= form_for(@user, remote: true) do |f| %>
+<%= form_with(model: @user) do |f| %>
   <%= f.label :name %><br>
   <%= f.text_field :name %>
   <%= f.submit %>