13 files changed, 87 insertions, 19 deletions
diff --git a/actionmailer/lib/action_mailer/mail_helper.rb b/actionmailer/lib/action_mailer/mail_helper.rb
index 8d6e082d02..54ad9f066f 100644
--- a/actionmailer/lib/action_mailer/mail_helper.rb
+++ b/actionmailer/lib/action_mailer/mail_helper.rb
@@ -50,7 +50,7 @@ module ActionMailer
       end
 
       indentation = " " * indent
-      sentences.map { |sentence|
+      sentences.map! { |sentence|
         "#{indentation}#{sentence.join(' ')}"
       }.join "\n"
     end
diff --git a/actionmailer/test/abstract_unit.rb b/actionmailer/test/abstract_unit.rb
index 15729bafba..ed8cf72cd0 100644
--- a/actionmailer/test/abstract_unit.rb
+++ b/actionmailer/test/abstract_unit.rb
@@ -59,5 +59,3 @@ end
 def restore_delivery_method
   ActionMailer::Base.delivery_method = @old_delivery_method
 end
-
-ActiveSupport::Deprecation.silenced = true
diff --git a/actionpack/lib/action_controller/base.rb b/actionpack/lib/action_controller/base.rb
index 168ae0a529..1faecc850b 100644
--- a/actionpack/lib/action_controller/base.rb
+++ b/actionpack/lib/action_controller/base.rb
@@ -3,7 +3,7 @@ require "action_controller/metal/params_wrapper"
 
 module ActionController
   # Action Controllers are the core of a web request in \Rails. They are made up of one or more actions that are executed
-  # on request and then either render a template or redirect to another action. An action is defined as a public method
+  # on request and then either it renders a template or redirects to another action. An action is defined as a public method
   # on the controller, which will automatically be made accessible to the web-server through \Rails Routes.
   #
   # By default, only the ApplicationController in a \Rails application inherits from <tt>ActionController::Base</tt>. All other
diff --git a/actionview/CHANGELOG.md b/actionview/CHANGELOG.md
index b45d5bf1e0..adbe8ac389 100644
--- a/actionview/CHANGELOG.md
+++ b/actionview/CHANGELOG.md
@@ -1,5 +1,5 @@
 *   Fix `current_page?` when the URL contains escaped characters and the
-    original URL is using the hexdecimal lowercased.
+    original URL is using the hexadecimal lowercased.
 
     *Rafael Mendonça França*
 
diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 70d7988e94..74f2b2287f 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,8 @@
+*   Removed redundant override of `xml` column definition for PG,
+    in order to use `xml` column type instead of `text`.
+
+    *Paul Nikitochkin*, *Michael Nikitochkin*
+
 *   Revert `ActiveRecord::Relation#order` change that make new order
     prepend the old one.
 
@@ -34,7 +39,7 @@
 
 *   When using optimistic locking, `update` was not passing the column to `quote_value`
     to allow the connection adapter to properly determine how to quote the value. This was
-    affecting certain databases that use specific colmn types.
+    affecting certain databases that use specific column types.
 
     Fixes: #6763
 
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index b82d0fb872..ba1cb05d2c 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -291,6 +291,14 @@ module ActiveRecord
         false
       end
 
+      # This is meant to be implemented by the adapters that support extensions
+      def disable_extension(name)
+      end
+
+      # This is meant to be implemented by the adapters that support extensions
+      def enable_extension(name)
+      end
+
       # A list of extensions, to be filled in by adapters that support them. At
       # the moment only postgresql does.
       def extensions
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 98126249df..342d1b1433 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -373,15 +373,11 @@ module ActiveRecord
           self
         end
 
-        def xml(options = {})
-          column(args[0], :text, options)
-        end
-
         private
 
-        def create_column_definition(name, type)
-          ColumnDefinition.new name, type
-        end
+          def create_column_definition(name, type)
+            ColumnDefinition.new name, type
+          end
       end
 
       class Table < ActiveRecord::ConnectionAdapters::Table
diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
index e088021112..2b1e997ef4 100644
--- a/activerecord/lib/active_record/core.rb
+++ b/activerecord/lib/active_record/core.rb
@@ -134,13 +134,12 @@ module ActiveRecord
 
       # Returns the Arel engine.
       def arel_engine
-        @arel_engine ||= begin
+        @arel_engine ||=
           if Base == self || connection_handler.retrieve_connection_pool(self)
             self
           else
             superclass.arel_engine
           end
-        end
       end
 
       private
@@ -347,7 +346,7 @@ module ActiveRecord
 
     # Returns a hash of the given methods with their names as keys and returned values as values.
     def slice(*methods)
-      Hash[methods.map { |method| [method, public_send(method)] }].with_indifferent_access
+      Hash[methods.map! { |method| [method, public_send(method)] }].with_indifferent_access
     end
 
     def set_transaction_state(state) # :nodoc:
diff --git a/activerecord/test/cases/adapters/mysql/mysql_adapter_test.rb b/activerecord/test/cases/adapters/mysql/mysql_adapter_test.rb
index 4a23287448..9ad0744aee 100644
--- a/activerecord/test/cases/adapters/mysql/mysql_adapter_test.rb
+++ b/activerecord/test/cases/adapters/mysql/mysql_adapter_test.rb
@@ -108,6 +108,18 @@ module ActiveRecord
         assert_equal 2, result.column_types['status'].type_cast(result.last['status'])
       end
 
+      def test_supports_extensions
+        assert_not @conn.supports_extensions?, 'does not support extensions'
+      end
+
+      def test_respond_to_enable_extension
+        assert @conn.respond_to?(:enable_extension)
+      end
+
+      def test_respond_to_disable_extension
+        assert @conn.respond_to?(:disable_extension)
+      end
+
       private
       def insert(ctx, data, table='ex')
         binds   = data.map { |name, value|
diff --git a/activerecord/test/cases/adapters/postgresql/xml_test.rb b/activerecord/test/cases/adapters/postgresql/xml_test.rb
new file mode 100644
index 0000000000..bf14b378d8
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/xml_test.rb
@@ -0,0 +1,38 @@
+# encoding: utf-8
+
+require 'cases/helper'
+require 'active_record/base'
+require 'active_record/connection_adapters/postgresql_adapter'
+
+class PostgresqlXMLTest < ActiveRecord::TestCase
+  class XmlDataType < ActiveRecord::Base
+    self.table_name = 'xml_data_type'
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    begin
+      @connection.transaction do
+        @connection.create_table('xml_data_type') do |t|
+          t.xml 'payload', default: {}
+        end
+      end
+    rescue ActiveRecord::StatementInvalid
+      return skip "do not test on PG without xml"
+    end
+    @column = XmlDataType.columns.find { |c| c.name == 'payload' }
+  end
+
+  def teardown
+    @connection.execute 'drop table if exists xml_data_type'
+  end
+
+  def test_column
+    assert_equal :xml, @column.type
+  end
+
+  def test_null_xml
+    @connection.execute %q|insert into xml_data_type (payload) VALUES(null)|
+    assert_nil XmlDataType.first.payload
+  end
+end
diff --git a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
index a8e5ab81e4..6ba6518eaa 100644
--- a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
+++ b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
@@ -354,6 +354,18 @@ module ActiveRecord
         assert_nil @conn.primary_key('failboat')
       end
 
+      def test_supports_extensions
+        assert_not @conn.supports_extensions?, 'does not support extensions'
+      end
+
+      def test_respond_to_enable_extension
+        assert @conn.respond_to?(:enable_extension)
+      end
+
+      def test_respond_to_disable_extension
+        assert @conn.respond_to?(:disable_extension)
+      end
+
       private
 
       def assert_logged logs
diff --git a/guides/source/getting_started.md b/guides/source/getting_started.md
index 58bf8bbe90..27768952cc 100644
--- a/guides/source/getting_started.md
+++ b/guides/source/getting_started.md
@@ -621,9 +621,9 @@ it! You should get an error that looks like this:
 
 Rails has several security features that help you write secure applications,
 and you're running into one of them now. This one is called
-'strong_parameters,' which requires us to tell Rails exactly which parameters
+`strong_parameters`, which requires us to tell Rails exactly which parameters
 we want to accept in our controllers. In this case, we want to allow the
-'title' and 'text' parameters, so change your `create` controller action to
+`title` and `text` parameters, so change your `create` controller action to
 look like this:
 
 ```
diff --git a/railties/lib/rails/info.rb b/railties/lib/rails/info.rb
index 5b69605b51..edadeaca0e 100644
--- a/railties/lib/rails/info.rb
+++ b/railties/lib/rails/info.rb
@@ -23,7 +23,7 @@ module Rails
       end
 
       def frameworks
-        %w( active_record action_pack action_mailer active_support )
+        %w( active_record action_pack action_view action_mailer active_support )
       end
 
       def framework_version(framework)