10 files changed, 55 insertions, 67 deletions
diff --git a/guides/source/4_0_release_notes.md b/guides/source/4_0_release_notes.md
index 9c157ec0b3..463da488f2 100644
--- a/guides/source/4_0_release_notes.md
+++ b/guides/source/4_0_release_notes.md
@@ -200,6 +200,8 @@ Please refer to the [Changelog](https://github.com/rails/rails/blob/master/activ
 
 *   Remove IdentityMap.
 
+*   Remove automatic execution of EXPLAIN queries. The option `active_record.auto_explain_threshold_in_seconds` is no longer used and should be removed.
+
 *   Adds `ActiveRecord::NullRelation` and `ActiveRecord::Relation#none` implementing the null object pattern for the Relation class.
 
 *   Added `create_join_table` migration helper to create HABTM join tables.
diff --git a/guides/source/action_mailer_basics.md b/guides/source/action_mailer_basics.md
index 513ae1272f..8720aae169 100644
--- a/guides/source/action_mailer_basics.md
+++ b/guides/source/action_mailer_basics.md
@@ -116,7 +116,7 @@ Setting this up is painfully simple.
 First off, we need to create a simple `User` scaffold:
 
 ```bash
-$ rails generate scaffold user name:string email:string login:string
+$ rails generate scaffold user name email login
 $ rake db:migrate
 ```
 
@@ -447,7 +447,7 @@ end
 Action Mailer Callbacks
 ---------------------------
 
-Action Mailer allows for you to specify a `before_action`, `after_action` and 'around_action'.
+Action Mailer allows for you to specify a `before_action`, `after_action` and `around_action`.
 
 * Filters can be specified with a block or a symbol to a method in the mailer class similar to controllers.
 
@@ -507,7 +507,6 @@ The following configuration options are best made in one of the environment file
 
 | Configuration | Description |
 |---------------|-------------|
-|`template_root`|Determines the base from which template references will be made.|
 |`logger`|Generates information on the mailing run if available. Can be set to `nil` for no logging. Compatible with both Ruby's own `Logger` and `Log4r` loggers.|
 |`smtp_settings`|Allows detailed configuration for `:smtp` delivery method:<ul><li>`:address` - Allows you to use a remote mail server. Just change it from its default "localhost" setting.</li><li>`:port`  - On the off chance that your mail server doesn't run on port 25, you can change it.</li><li>`:domain` - If you need to specify a HELO domain, you can do it here.</li><li>`:user_name` - If your mail server requires authentication, set the username in this setting.</li><li>`:password` - If your mail server requires authentication, set the password in this setting.</li><li>`:authentication` - If your mail server requires authentication, you need to specify the authentication type here. This is a symbol and one of `:plain`, `:login`, `:cram_md5`.</li><li>`:enable_starttls_auto` - Set this to `false` if there is a problem with your server certificate that you cannot resolve.</li></ul>|
 |`sendmail_settings`|Allows you to override options for the `:sendmail` delivery method.<ul><li>`:location` - The location of the sendmail executable. Defaults to `/usr/sbin/sendmail`.</li><li>`:arguments` - The command line arguments to be passed to sendmail. Defaults to `-i -t`.</li></ul>|
diff --git a/guides/source/active_record_callbacks.md b/guides/source/active_record_callbacks.md
index 516457bcd3..bb42fab101 100644
--- a/guides/source/active_record_callbacks.md
+++ b/guides/source/active_record_callbacks.md
@@ -342,19 +342,17 @@ By using the `after_commit` callback we can account for this case.
 
 ```ruby
 class PictureFile < ActiveRecord::Base
-  attr_accessor :delete_file
+  after_commit :delete_picture_file_from_disk, :on => [:destroy]
 
-  after_destroy do |picture_file|
-    picture_file.delete_file = picture_file.filepath
-  end
-
-  after_commit do |picture_file|
-    if picture_file.delete_file && File.exist?(picture_file.delete_file)
-      File.delete(picture_file.delete_file)
-      picture_file.delete_file = nil
+  def delete_picture_file_from_disk
+    if File.exist?(filepath)
+      File.delete(filepath)
     end
   end
 end
 ```
 
+NOTE: the `:on` option specifies when a callback will be fired. If you
+don't supply the `:on` option the callback will fire for every action.
+
 The `after_commit` and `after_rollback` callbacks are guaranteed to be called for all models created, updated, or destroyed within a transaction block. If any exceptions are raised within one of these callbacks, they will be ignored so that they don't interfere with the other callbacks. As such, if your callback code could raise an exception, you'll need to rescue it and handle it appropriately within the callback.
diff --git a/guides/source/active_record_querying.md b/guides/source/active_record_querying.md
index 62d6294ae5..5d82541da9 100644
--- a/guides/source/active_record_querying.md
+++ b/guides/source/active_record_querying.md
@@ -299,7 +299,7 @@ Client.first(2)
 The SQL equivalent of the above is:
 
 ```sql
-SELECT * FROM clients LIMIT 2
+SELECT * FROM clients ORDER BY id ASC LIMIT 2
 ```
 
 #### last
@@ -315,7 +315,7 @@ Client.last(2)
 The SQL equivalent of the above is:
 
 ```sql
-SELECT * FROM clients ORDER By id DESC LIMIT 2
+SELECT * FROM clients ORDER BY id DESC LIMIT 2
 ```
 
 ### Retrieving Multiple Objects in Batches
@@ -1609,45 +1609,6 @@ EXPLAIN for: SELECT `posts`.* FROM `posts`  WHERE `posts`.`user_id` IN (1)
 
 under MySQL.
 
-### Automatic EXPLAIN
-
-Active Record is able to run EXPLAIN automatically on slow queries and log its
-output. This feature is controlled by the configuration parameter
-
-```ruby
-config.active_record.auto_explain_threshold_in_seconds
-```
-
-If set to a number, any query exceeding those many seconds will have its EXPLAIN
-automatically triggered and logged. In the case of relations, the threshold is
-compared to the total time needed to fetch records. So, a relation is seen as a
-unit of work, no matter whether the implementation of eager loading involves
-several queries under the hood.
-
-A threshold of `nil` disables automatic EXPLAINs.
-
-The default threshold in development mode is 0.5 seconds, and `nil` in test and
-production modes.
-
-INFO. Automatic EXPLAIN gets disabled if Active Record has no logger, regardless
-of the value of the threshold.
-
-#### Disabling Automatic EXPLAIN
-
-Automatic EXPLAIN can be selectively silenced with `ActiveRecord::Base.silence_auto_explain`:
-
-```ruby
-ActiveRecord::Base.silence_auto_explain do
-  # no automatic EXPLAIN is triggered here
-end
-```
-
-That may be useful for queries you know are slow but fine, like a heavyweight
-report of an admin interface.
-
-As its name suggests, `silence_auto_explain` only silences automatic EXPLAINs.
-Explicit calls to `ActiveRecord::Relation#explain` run.
-
 ### Interpreting EXPLAIN
 
 Interpretation of the output of EXPLAIN is beyond the scope of this guide. The
diff --git a/guides/source/active_support_core_extensions.md b/guides/source/active_support_core_extensions.md
index f02b377832..517db0d222 100644
--- a/guides/source/active_support_core_extensions.md
+++ b/guides/source/active_support_core_extensions.md
@@ -3320,7 +3320,25 @@ date.end_of_hour # => Mon Jun 07 19:59:59 +0200 2010
 
 `beginning_of_hour` is aliased to `at_beginning_of_hour`.
 
-INFO: `beginning_of_hour` and `end_of_hour` are implemented for `Time` and `DateTime` but **not** `Date` as it does not make sense to request the beginning or end of an hour on a `Date` instance.
+##### `beginning_of_minute`, `end_of_minute`
+
+The method `beginning_of_minute` returns a timestamp at the beginning of the minute (hh:mm:00):
+
+```ruby
+date = DateTime.new(2010, 6, 7, 19, 55, 25)
+date.beginning_of_minute # => Mon Jun 07 19:55:00 +0200 2010
+```
+
+The method `end_of_minute` returns a timestamp at the end of the minute (hh:mm:59):
+
+```ruby
+date = DateTime.new(2010, 6, 7, 19, 55, 25)
+date.end_of_minute # => Mon Jun 07 19:55:59 +0200 2010
+```
+
+`beginning_of_minute` is aliased to `at_beginning_of_minute`.
+
+INFO: `beginning_of_hour`, `end_of_hour`, `beginning_of_minute` and `end_of_minute` are implemented for `Time` and `DateTime` but **not** `Date` as it does not make sense to request the beginning or end of an hour or minute on a `Date` instance.
 
 ##### `ago`, `since`
 
diff --git a/guides/source/caching_with_rails.md b/guides/source/caching_with_rails.md
index a270ec7a7e..abab3dd983 100644
--- a/guides/source/caching_with_rails.md
+++ b/guides/source/caching_with_rails.md
@@ -343,8 +343,3 @@ class ProductsController < ApplicationController
   end
 end
 ```
-
-Further reading
----------------
-
-* [Scaling Rails Screencasts](http://railslab.newrelic.com/scaling-rails)
diff --git a/guides/source/configuring.md b/guides/source/configuring.md
index be46e15078..dbbeec7126 100644
--- a/guides/source/configuring.md
+++ b/guides/source/configuring.md
@@ -268,8 +268,6 @@ config.middleware.delete "Rack::MethodOverride"
 
 * `config.active_record.lock_optimistically` controls whether Active Record will use optimistic locking and is true by default.
 
-* `config.active_record.auto_explain_threshold_in_seconds` configures the threshold for automatic EXPLAINs (`nil` disables this feature). Queries exceeding the threshold get their query plan logged. Default is 0.5 in development mode.
-
 * +config.active_record.cache_timestamp_format+ controls the format of the timestamp value in the cache key. Default is +:number+.
 
 The MySQL adapter adds one additional configuration option:
diff --git a/guides/source/layouts_and_rendering.md b/guides/source/layouts_and_rendering.md
index 339008ab9e..bfd1a7c61b 100644
--- a/guides/source/layouts_and_rendering.md
+++ b/guides/source/layouts_and_rendering.md
@@ -568,7 +568,8 @@ def show
   @book = Book.find_by_id(params[:id])
   if @book.nil?
     @books = Book.all
-    render "index", alert: "Your book was not found!"
+    flash[:alert] = "Your book was not found"
+    render "index"
   end
 end
 ```
diff --git a/guides/source/routing.md b/guides/source/routing.md
index 4614169653..d7a4a237ed 100644
--- a/guides/source/routing.md
+++ b/guides/source/routing.md
@@ -155,7 +155,7 @@ creates six different routes in your application, all mapping to the `Geocoders`
 | PATCH/PUT | /geocoder      | update  | update the one and only geocoder resource     |
 | DELETE    | /geocoder      | destroy | delete the geocoder resource                  |
 
-NOTE: Because you might want to use the same controller for a singular route (`/account`) and a plural route (`/accounts/45`), singular resources map to plural controllers.
+NOTE: Because you might want to use the same controller for a singular route (`/account`) and a plural route (`/accounts/45`), singular resources map to plural controllers. So that, for example, `resource :photo` and `resources :photos` creates both singular and plural routes that map to the same controller (`PhotosController`).
 
 A singular resourceful route generates these helpers:
 
@@ -797,6 +797,16 @@ You should put the `root` route at the top of the file, because it is the most p
 
 NOTE: The `root` route only routes `GET` requests to the action.
 
+You can also use root inside namespaces and scopes as well.  For example:
+
+```ruby
+namespace :admin do
+  root to: "admin#index"
+end
+
+root to: "home#index"
+```
+
 ### Unicode character routes
 
 You can specify unicode character routes directly. For example:
diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md
index 18baed55b5..52f5232efc 100644
--- a/guides/source/upgrading_ruby_on_rails.md
+++ b/guides/source/upgrading_ruby_on_rails.md
@@ -45,6 +45,12 @@ Rails 4.0 no longer supports loading plugins from `vendor/plugins`. You must rep
 
 * Rails 4.0 has changed `serialized_attributes` and `attr_readonly` to class methods only. Now you shouldn't use instance methods, it's deprecated. You must change them, e.g. `self.serialized_attributes` to `self.class.serialized_attributes`.
 
+* Rails 4.0 has removed `attr_accessible` and `attr_protected` feature in favor of Strong Parameters. You can use the [Protected Attributes gem](https://github.com/rails/protected_attributes) to a smoothly upgrade path.
+
+### Active Resource
+
+Rails 4.0 extracted Active Resource to its own gem. If you still need the feature you can add the [Active Resource gem](https://github.com/rails/activeresource) in your Gemfile.
+
 ### Active Model
 
 * Rails 4.0 has changed how errors attach with the `ActiveModel::Validations::ConfirmationValidator`. Now when confirmation validations fail the error will be attached to `:#{attribute}_confirmation` instead of `attribute`.
@@ -108,14 +114,14 @@ Upgrading from Rails 3.1 to Rails 3.2
 
 If your application is currently on any version of Rails older than 3.1.x, you should upgrade to Rails 3.1 before attempting an update to Rails 3.2.
 
-The following changes are meant for upgrading your application to Rails 3.2.2, the latest 3.2.x version of Rails.
+The following changes are meant for upgrading your application to Rails 3.2.12, the latest 3.2.x version of Rails.
 
 ### Gemfile
 
 Make the following changes to your `Gemfile`.
 
 ```ruby
-gem 'rails', '= 3.2.2'
+gem 'rails', '= 3.2.12'
 
 group :assets do
   gem 'sass-rails',   '~> 3.2.3'
@@ -155,14 +161,14 @@ Upgrading from Rails 3.0 to Rails 3.1
 
 If your application is currently on any version of Rails older than 3.0.x, you should upgrade to Rails 3.0 before attempting an update to Rails 3.1.
 
-The following changes are meant for upgrading your application to Rails 3.1.3, the latest 3.1.x version of Rails.
+The following changes are meant for upgrading your application to Rails 3.1.11, the latest 3.1.x version of Rails.
 
 ### Gemfile
 
 Make the following changes to your `Gemfile`.
 
 ```ruby
-gem 'rails', '= 3.1.3'
+gem 'rails', '= 3.1.11'
 gem 'mysql2'
 
 # Needed for the new asset pipeline