Remove XML Serialization from core.

This includes the following classes:

- ActiveModel::Serializers::Xml
- ActiveRecord::Serialization::XmlSerializer

13 files changed, 12 insertions, 1204 deletions

diff --git a/activemodel/CHANGELOG.md b/activemodel/CHANGELOG.md
index dddfd940bb..f25c901ecc 100644
--- a/activemodel/CHANGELOG.md
+++ b/activemodel/CHANGELOG.md
@@ -3,6 +3,10 @@
 
     *Jay Elaraj*
 
+*   Remove `ActiveModel::Serializers::Xml` from core.
+
+    *Zachary Scott*
+
 *   Add `ActiveModel::Dirty#[attr_name]_previously_changed?` and
     `ActiveModel::Dirty#[attr_name]_previous_change` to improve access
     to recorded changes after the model has been saved.
diff --git a/activemodel/README.rdoc b/activemodel/README.rdoc
index d954467387..20414c1d61 100644
--- a/activemodel/README.rdoc
+++ b/activemodel/README.rdoc
@@ -155,7 +155,7 @@ behavior out of the box:
 * Making objects serializable
 
   <tt>ActiveModel::Serialization</tt> provides a standard interface for your object
-  to provide +to_json+ or +to_xml+ serialization.
+  to provide +to_json+ serialization.
 
     class SerialPerson
       include ActiveModel::Serialization
@@ -177,13 +177,6 @@ behavior out of the box:
     s = SerialPerson.new
     s.to_json             # => "{\"name\":null}"
 
-    class SerialPerson
-      include ActiveModel::Serializers::Xml
-    end
-
-    s = SerialPerson.new
-    s.to_xml              # => "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<serial-person...
-
   {Learn more}[link:classes/ActiveModel/Serialization.html]
 
 * Internationalization (i18n) support
diff --git a/activemodel/lib/active_model.rb b/activemodel/lib/active_model.rb
index 8aa1b6f664..4e1b3f7495 100644
--- a/activemodel/lib/active_model.rb
+++ b/activemodel/lib/active_model.rb
@@ -58,7 +58,6 @@ module ActiveModel
 
     eager_autoload do
       autoload :JSON
-      autoload :Xml
     end
   end
 
diff --git a/activemodel/lib/active_model/serialization.rb b/activemodel/lib/active_model/serialization.rb
index f95849eb84..58d68d9620 100644
--- a/activemodel/lib/active_model/serialization.rb
+++ b/activemodel/lib/active_model/serialization.rb
@@ -40,7 +40,6 @@ module ActiveModel
   #
   #   class Person
   #     include ActiveModel::Serializers::JSON
-  #     include ActiveModel::Serializers::Xml
   #
   #     attr_accessor :name
   #
@@ -55,13 +54,11 @@ module ActiveModel
   #   person.serializable_hash   # => {"name"=>nil}
   #   person.as_json             # => {"name"=>nil}
   #   person.to_json             # => "{\"name\":null}"
-  #   person.to_xml              # => "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<serial-person...
   #
   #   person.name = "Bob"
   #   person.serializable_hash   # => {"name"=>"Bob"}
   #   person.as_json             # => {"name"=>"Bob"}
   #   person.to_json             # => "{\"name\":\"Bob\"}"
-  #   person.to_xml              # => "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<serial-person...
   #
   # Valid options are <tt>:only</tt>, <tt>:except</tt>, <tt>:methods</tt> and
   # <tt>:include</tt>. The following are all valid examples:
diff --git a/activemodel/lib/active_model/serializers/xml.rb b/activemodel/lib/active_model/serializers/xml.rb
deleted file mode 100644
index e33c766627..0000000000
--- a/activemodel/lib/active_model/serializers/xml.rb
+++ /dev/null
@@ -1,238 +0,0 @@
-require 'active_support/core_ext/module/attribute_accessors'
-require 'active_support/core_ext/array/conversions'
-require 'active_support/core_ext/hash/conversions'
-require 'active_support/core_ext/hash/slice'
-require 'active_support/core_ext/time/acts_like'
-
-module ActiveModel
-  module Serializers
-    # == \Active \Model XML Serializer
-    module Xml
-      extend ActiveSupport::Concern
-      include ActiveModel::Serialization
-
-      included do
-        extend ActiveModel::Naming
-      end
-
-      class Serializer #:nodoc:
-        class Attribute #:nodoc:
-          attr_reader :name, :value, :type
-
-          def initialize(name, serializable, value)
-            @name, @serializable = name, serializable
-
-            if value.acts_like?(:time) && value.respond_to?(:in_time_zone)
-              value  = value.in_time_zone
-            end
-
-            @value = value
-            @type  = compute_type
-          end
-
-          def decorations
-            decorations = {}
-            decorations[:encoding] = 'base64' if type == :binary
-            decorations[:type] = (type == :string) ? nil : type
-            decorations[:nil] = true if value.nil?
-            decorations
-          end
-
-        protected
-
-          def compute_type
-            return if value.nil?
-            type = ActiveSupport::XmlMini::TYPE_NAMES[value.class.name]
-            type ||= :string if value.respond_to?(:to_str)
-            type ||= :yaml
-            type
-          end
-        end
-
-        class MethodAttribute < Attribute #:nodoc:
-        end
-
-        attr_reader :options
-
-        def initialize(serializable, options = nil)
-          @serializable = serializable
-          @options = options ? options.dup : {}
-        end
-
-        def serializable_hash
-          @serializable.serializable_hash(@options.except(:include))
-        end
-
-        def serializable_collection
-          methods = Array(options[:methods]).map(&:to_s)
-          serializable_hash.map do |name, value|
-            name = name.to_s
-            if methods.include?(name)
-              self.class::MethodAttribute.new(name, @serializable, value)
-            else
-              self.class::Attribute.new(name, @serializable, value)
-            end
-          end
-        end
-
-        def serialize
-          require 'builder' unless defined? ::Builder
-
-          options[:indent]  ||= 2
-          options[:builder] ||= ::Builder::XmlMarkup.new(indent: options[:indent])
-
-          @builder = options[:builder]
-          @builder.instruct! unless options[:skip_instruct]
-
-          root = (options[:root] || @serializable.model_name.element).to_s
-          root = ActiveSupport::XmlMini.rename_key(root, options)
-
-          args = [root]
-          args << { xmlns: options[:namespace] } if options[:namespace]
-          args << { type: options[:type] } if options[:type] && !options[:skip_types]
-
-          @builder.tag!(*args) do
-            add_attributes_and_methods
-            add_includes
-            add_extra_behavior
-            add_procs
-            yield @builder if block_given?
-          end
-        end
-
-      private
-
-        def add_extra_behavior
-        end
-
-        def add_attributes_and_methods
-          serializable_collection.each do |attribute|
-            key = ActiveSupport::XmlMini.rename_key(attribute.name, options)
-            ActiveSupport::XmlMini.to_tag(key, attribute.value,
-              options.merge(attribute.decorations))
-          end
-        end
-
-        def add_includes
-          @serializable.send(:serializable_add_includes, options) do |association, records, opts|
-            add_associations(association, records, opts)
-          end
-        end
-
-        # TODO: This can likely be cleaned up to simple use ActiveSupport::XmlMini.to_tag as well.
-        def add_associations(association, records, opts)
-          merged_options = opts.merge(options.slice(:builder, :indent))
-          merged_options[:skip_instruct] = true
-
-          [:skip_types, :dasherize, :camelize].each do |key|
-            merged_options[key] = options[key] if merged_options[key].nil? && !options[key].nil?
-          end
-
-          if records.respond_to?(:to_ary)
-            records = records.to_ary
-
-            tag  = ActiveSupport::XmlMini.rename_key(association.to_s, options)
-            type = options[:skip_types] ? { } : { type: "array" }
-            association_name = association.to_s.singularize
-            merged_options[:root] = association_name
-
-            if records.empty?
-              @builder.tag!(tag, type)
-            else
-              @builder.tag!(tag, type) do
-                records.each do |record|
-                  if options[:skip_types]
-                    record_type = {}
-                  else
-                    record_class = (record.class.to_s.underscore == association_name) ? nil : record.class.name
-                    record_type = { type: record_class }
-                  end
-
-                  record.to_xml merged_options.merge(record_type)
-                end
-              end
-            end
-          else
-            merged_options[:root] = association.to_s
-
-            unless records.class.to_s.underscore == association.to_s
-              merged_options[:type] = records.class.name
-            end
-
-            records.to_xml merged_options
-          end
-        end
-
-        def add_procs
-          if procs = options.delete(:procs)
-            Array(procs).each do |proc|
-              if proc.arity == 1
-                proc.call(options)
-              else
-                proc.call(options, @serializable)
-              end
-            end
-          end
-        end
-      end
-
-      # Returns XML representing the model. Configuration can be
-      # passed through +options+.
-      #
-      # Without any +options+, the returned XML string will include all the
-      # model's attributes.
-      #
-      #   user = User.find(1)
-      #   user.to_xml
-      #
-      #   <?xml version="1.0" encoding="UTF-8"?>
-      #   <user>
-      #     <id type="integer">1</id>
-      #     <name>David</name>
-      #     <age type="integer">16</age>
-      #     <created-at type="dateTime">2011-01-30T22:29:23Z</created-at>
-      #   </user>
-      #
-      # The <tt>:only</tt> and <tt>:except</tt> options can be used to limit the
-      # attributes included, and work similar to the +attributes+ method.
-      #
-      # To include the result of some method calls on the model use <tt>:methods</tt>.
-      #
-      # To include associations use <tt>:include</tt>.
-      #
-      # For further documentation, see <tt>ActiveRecord::Serialization#to_xml</tt>
-      def to_xml(options = {}, &block)
-        Serializer.new(self, options).serialize(&block)
-      end
-
-      # Sets the model +attributes+ from an XML string. Returns +self+.
-      #
-      #   class Person
-      #     include ActiveModel::Serializers::Xml
-      #
-      #     attr_accessor :name, :age, :awesome
-      #
-      #     def attributes=(hash)
-      #       hash.each do |key, value|
-      #         instance_variable_set("@#{key}", value)
-      #       end
-      #     end
-      #
-      #     def attributes
-      #       instance_values
-      #     end
-      #   end
-      #
-      #   xml = { name: 'bob', age: 22, awesome:true }.to_xml
-      #   person = Person.new
-      #   person.from_xml(xml) # => #<Person:0x007fec5e3b3c40 @age=22, @awesome=true, @name="bob">
-      #   person.name          # => "bob"
-      #   person.age           # => 22
-      #   person.awesome       # => true
-      def from_xml(xml)
-        self.attributes = Hash.from_xml(xml).values.first
-        self
-      end
-    end
-  end
-end
diff --git a/activemodel/test/cases/serializers/xml_serialization_test.rb b/activemodel/test/cases/serializers/xml_serialization_test.rb
deleted file mode 100644
index 37faf6cef8..0000000000
--- a/activemodel/test/cases/serializers/xml_serialization_test.rb
+++ /dev/null
@@ -1,251 +0,0 @@
-require 'cases/helper'
-require 'models/contact'
-require 'active_support/core_ext/object/instance_variables'
-require 'ostruct'
-require 'yaml'
-
-module Admin
-  class Contact < ::Contact
-  end
-end
-
-class Customer < Struct.new(:name)
-end
-
-class Address
-  include ActiveModel::Serializers::Xml
-
-  attr_accessor :street, :city, :state, :zip, :apt_number
-
-  def attributes
-    instance_values
-  end
-end
-
-class SerializableContact < Contact
-  def serializable_hash(options={})
-    super(options.merge(only: [:name, :age]))
-  end
-end
-
-class XmlSerializationTest < ActiveModel::TestCase
-  def setup
-    @contact = Contact.new
-    @contact.name = 'aaron stack'
-    @contact.age = 25
-    @contact.created_at = Time.utc(2006, 8, 1)
-    @contact.awesome = false
-    customer = Customer.new
-    customer.name = "John"
-    @contact.preferences = customer
-    @contact.address = Address.new
-    @contact.address.city = "Springfield"
-    @contact.address.apt_number = 35
-    @contact.friends = [Contact.new, Contact.new]
-    @contact.contact = SerializableContact.new
-  end
-
-  test "should serialize default root" do
-    xml = @contact.to_xml
-    assert_match %r{^<contact>},  xml
-    assert_match %r{</contact>$}, xml
-  end
-
-  test "should serialize namespaced root" do
-    xml = Admin::Contact.new(@contact.attributes).to_xml
-    assert_match %r{^<contact>},  xml
-    assert_match %r{</contact>$}, xml
-  end
-
-  test "should serialize default root with namespace" do
-    xml = @contact.to_xml namespace: "http://xml.rubyonrails.org/contact"
-    assert_match %r{^<contact xmlns="http://xml.rubyonrails.org/contact">}, xml
-    assert_match %r{</contact>$}, xml
-  end
-
-  test "should serialize custom root" do
-    xml = @contact.to_xml root: 'xml_contact'
-    assert_match %r{^<xml-contact>},  xml
-    assert_match %r{</xml-contact>$}, xml
-  end
-
-  test "should allow undasherized tags" do
-    xml = @contact.to_xml root: 'xml_contact', dasherize: false
-    assert_match %r{^<xml_contact>},  xml
-    assert_match %r{</xml_contact>$}, xml
-    assert_match %r{<created_at},     xml
-  end
-
-  test "should allow camelized tags" do
-    xml = @contact.to_xml root: 'xml_contact', camelize: true
-    assert_match %r{^<XmlContact>},  xml
-    assert_match %r{</XmlContact>$}, xml
-    assert_match %r{<CreatedAt},     xml
-  end
-
-  test "should allow lower-camelized tags" do
-    xml = @contact.to_xml root: 'xml_contact', camelize: :lower
-    assert_match %r{^<xmlContact>},  xml
-    assert_match %r{</xmlContact>$}, xml
-    assert_match %r{<createdAt},     xml
-  end
-
-  test "should use serializable hash" do
-    @contact = SerializableContact.new
-    @contact.name = 'aaron stack'
-    @contact.age = 25
-
-    xml = @contact.to_xml
-    assert_match %r{<name>aaron stack</name>}, xml
-    assert_match %r{<age type="integer">25</age>}, xml
-    assert_no_match %r{<awesome>}, xml
-  end
-
-  test "should allow skipped types" do
-    xml = @contact.to_xml skip_types: true
-    assert_match %r{<age>25</age>}, xml
-  end
-
-  test "should include yielded additions" do
-    xml_output = @contact.to_xml do |xml|
-      xml.creator "David"
-    end
-    assert_match %r{<creator>David</creator>}, xml_output
-  end
-
-  test "should serialize string" do
-    assert_match %r{<name>aaron stack</name>}, @contact.to_xml
-  end
-
-  test "should serialize nil" do
-    assert_match %r{<pseudonyms nil="true"/>}, @contact.to_xml(methods: :pseudonyms)
-  end
-
-  test "should serialize integer" do
-    assert_match %r{<age type="integer">25</age>}, @contact.to_xml
-  end
-
-  test "should serialize datetime" do
-    assert_match %r{<created-at type="dateTime">2006-08-01T00:00:00Z</created-at>}, @contact.to_xml
-  end
-
-  test "should serialize boolean" do
-    assert_match %r{<awesome type="boolean">false</awesome>}, @contact.to_xml
-  end
-
-  test "should serialize array" do
-    assert_match %r{<social type="array">\s*<social>twitter</social>\s*<social>github</social>\s*</social>}, @contact.to_xml(methods: :social)
-  end
-
-  test "should serialize hash" do
-    assert_match %r{<network>\s*<git type="symbol">github</git>\s*</network>}, @contact.to_xml(methods: :network)
-  end
-
-  test "should serialize yaml" do
-    assert_match %r{<preferences type="yaml">--- !ruby/struct:Customer(\s*)\nname: John\n</preferences>}, @contact.to_xml
-  end
-
-  test "should call proc on object" do
-    proc = Proc.new { |options| options[:builder].tag!('nationality', 'unknown') }
-    xml = @contact.to_xml(procs: [ proc ])
-    assert_match %r{<nationality>unknown</nationality>}, xml
-  end
-
-  test "should supply serializable to second proc argument" do
-    proc = Proc.new { |options, record| options[:builder].tag!('name-reverse', record.name.reverse) }
-    xml = @contact.to_xml(procs: [ proc ])
-    assert_match %r{<name-reverse>kcats noraa</name-reverse>}, xml
-  end
-
-  test "should serialize string correctly when type passed" do
-    xml = @contact.to_xml type: 'Contact'
-    assert_match %r{<contact type="Contact">}, xml
-    assert_match %r{<name>aaron stack</name>}, xml
-  end
-
-  test "include option with singular association" do
-    xml = @contact.to_xml include: :address, indent: 0
-    assert xml.include?(@contact.address.to_xml(indent: 0, skip_instruct: true))
-  end
-
-  test "include option with plural association" do
-    xml = @contact.to_xml include: :friends, indent: 0
-    assert_match %r{<friends type="array">}, xml
-    assert_match %r{<friend type="Contact">}, xml
-  end
-
-  class FriendList
-    def initialize(friends)
-      @friends = friends
-    end
-
-    def to_ary
-      @friends
-    end
-  end
-
-  test "include option with ary" do
-    @contact.friends = FriendList.new(@contact.friends)
-    xml = @contact.to_xml include: :friends, indent: 0
-    assert_match %r{<friends type="array">}, xml
-    assert_match %r{<friend type="Contact">}, xml
-  end
-
-  test "multiple includes" do
-    xml = @contact.to_xml indent: 0, skip_instruct: true, include: [ :address, :friends ]
-    assert xml.include?(@contact.address.to_xml(indent: 0, skip_instruct: true))
-    assert_match %r{<friends type="array">}, xml
-    assert_match %r{<friend type="Contact">}, xml
-  end
-
-  test "include with options" do
-    xml = @contact.to_xml indent: 0, skip_instruct: true, include: { address: { only: :city } }
-    assert xml.include?(%(><address><city>Springfield</city></address>))
-  end
-
-  test "propagates skip_types option to included associations" do
-    xml = @contact.to_xml include: :friends, indent: 0, skip_types: true
-    assert_match %r{<friends>}, xml
-    assert_match %r{<friend>}, xml
-  end
-
-  test "propagates skip-types option to included associations and attributes" do
-    xml = @contact.to_xml skip_types: true, include: :address, indent: 0
-    assert_match %r{<address>}, xml
-    assert_match %r{<apt-number>}, xml
-  end
-
-  test "propagates camelize option to included associations and attributes" do
-    xml = @contact.to_xml camelize: true, include: :address, indent: 0
-    assert_match %r{<Address>}, xml
-    assert_match %r{<AptNumber type="integer">}, xml
-  end
-
-  test "propagates dasherize option to included associations and attributes" do
-    xml = @contact.to_xml dasherize: false, include: :address, indent: 0
-    assert_match %r{<apt_number type="integer">}, xml
-  end
-
-  test "don't propagate skip_types if skip_types is defined at the included association level" do
-    xml = @contact.to_xml skip_types: true, include: { address: { skip_types: false } }, indent: 0
-    assert_match %r{<address>}, xml
-    assert_match %r{<apt-number type="integer">}, xml
-  end
-
-  test "don't propagate camelize if camelize is defined at the included association level" do
-    xml = @contact.to_xml camelize: true, include: { address: { camelize: false } }, indent: 0
-    assert_match %r{<address>}, xml
-    assert_match %r{<apt-number type="integer">}, xml
-  end
-
-  test "don't propagate dasherize if dasherize is defined at the included association level" do
-    xml = @contact.to_xml dasherize: false, include: { address: { dasherize: true } }, indent: 0
-    assert_match %r{<address>}, xml
-    assert_match %r{<apt-number type="integer">}, xml
-  end
-
-  test "association with sti" do
-    xml = @contact.to_xml(include: :contact)
-    assert xml.include?(%(<contact type="SerializableContact">))
-  end
-end
diff --git a/activemodel/test/models/contact.rb b/activemodel/test/models/contact.rb
index bcfd267a34..113ab0bc1f 100644
--- a/activemodel/test/models/contact.rb
+++ b/activemodel/test/models/contact.rb
@@ -4,7 +4,6 @@ class Contact
   include ActiveModel::Validations
 
   include ActiveModel::Serializers::JSON
-  include ActiveModel::Serializers::Xml
 
   attr_accessor :id, :name, :age, :created_at, :awesome, :preferences
   attr_accessor :address, :friends, :contact
diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 56aba1c483..c1ea8a3252 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -345,6 +345,10 @@
 
     *Ryuta Kamizono*
 
+*   Remove `ActiveRecord::Serialization::XmlSerializer` from core.
+
+    *Zachary Scott*
+
 *   Make `unscope` aware of "less than" and "greater than" conditions.
 
     *TAKAHASHI Kazuaki*
diff --git a/activerecord/lib/active_record/serialization.rb b/activerecord/lib/active_record/serialization.rb
index 48c12dcf9f..23dc6465af 100644
--- a/activerecord/lib/active_record/serialization.rb
+++ b/activerecord/lib/active_record/serialization.rb
@@ -18,5 +18,3 @@ module ActiveRecord #:nodoc:
     end
   end
 end
-
-require 'active_record/serializers/xml_serializer'
diff --git a/activerecord/lib/active_record/serializers/xml_serializer.rb b/activerecord/lib/active_record/serializers/xml_serializer.rb
deleted file mode 100644
index 89b7e0be82..0000000000
--- a/activerecord/lib/active_record/serializers/xml_serializer.rb
+++ /dev/null
@@ -1,193 +0,0 @@
-require 'active_support/core_ext/hash/conversions'
-
-module ActiveRecord #:nodoc:
-  module Serialization
-    include ActiveModel::Serializers::Xml
-
-    # Builds an XML document to represent the model. Some configuration is
-    # available through +options+. However more complicated cases should
-    # override ActiveRecord::Base#to_xml.
-    #
-    # By default the generated XML document will include the processing
-    # instruction and all the object's attributes. For example:
-    #
-    #   <?xml version="1.0" encoding="UTF-8"?>
-    #   <topic>
-    #     <title>The First Topic</title>
-    #     <author-name>David</author-name>
-    #     <id type="integer">1</id>
-    #     <approved type="boolean">false</approved>
-    #     <replies-count type="integer">0</replies-count>
-    #     <bonus-time type="dateTime">2000-01-01T08:28:00+12:00</bonus-time>
-    #     <written-on type="dateTime">2003-07-16T09:28:00+1200</written-on>
-    #     <content>Have a nice day</content>
-    #     <author-email-address>david@loudthinking.com</author-email-address>
-    #     <parent-id></parent-id>
-    #     <last-read type="date">2004-04-15</last-read>
-    #   </topic>
-    #
-    # This behavior can be controlled with <tt>:only</tt>, <tt>:except</tt>,
-    # <tt>:skip_instruct</tt>, <tt>:skip_types</tt>, <tt>:dasherize</tt> and <tt>:camelize</tt> .
-    # The <tt>:only</tt> and <tt>:except</tt> options are the same as for the
-    # +attributes+ method. The default is to dasherize all column names, but you
-    # can disable this setting <tt>:dasherize</tt> to +false+. Setting <tt>:camelize</tt>
-    # to +true+ will camelize all column names - this also overrides <tt>:dasherize</tt>.
-    # To not have the column type included in the XML output set <tt>:skip_types</tt> to +true+.
-    #
-    # For instance:
-    #
-    #   topic.to_xml(skip_instruct: true, except: [ :id, :bonus_time, :written_on, :replies_count ])
-    #
-    #   <topic>
-    #     <title>The First Topic</title>
-    #     <author-name>David</author-name>
-    #     <approved type="boolean">false</approved>
-    #     <content>Have a nice day</content>
-    #     <author-email-address>david@loudthinking.com</author-email-address>
-    #     <parent-id></parent-id>
-    #     <last-read type="date">2004-04-15</last-read>
-    #   </topic>
-    #
-    # To include first level associations use <tt>:include</tt>:
-    #
-    #   firm.to_xml include: [ :account, :clients ]
-    #
-    #   <?xml version="1.0" encoding="UTF-8"?>
-    #   <firm>
-    #     <id type="integer">1</id>
-    #     <rating type="integer">1</rating>
-    #     <name>37signals</name>
-    #     <clients type="array">
-    #       <client>
-    #         <rating type="integer">1</rating>
-    #         <name>Summit</name>
-    #       </client>
-    #       <client>
-    #         <rating type="integer">1</rating>
-    #         <name>Microsoft</name>
-    #       </client>
-    #     </clients>
-    #     <account>
-    #       <id type="integer">1</id>
-    #       <credit-limit type="integer">50</credit-limit>
-    #     </account>
-    #   </firm>
-    #
-    # Additionally, the record being serialized will be passed to a Proc's second
-    # parameter. This allows for ad hoc additions to the resultant document that
-    # incorporate the context of the record being serialized. And by leveraging the
-    # closure created by a Proc, to_xml can be used to add elements that normally fall
-    # outside of the scope of the model -- for example, generating and appending URLs
-    # associated with models.
-    #
-    #   proc = Proc.new { |options, record| options[:builder].tag!('name-reverse', record.name.reverse) }
-    #   firm.to_xml procs: [ proc ]
-    #
-    #   <firm>
-    #     # ... normal attributes as shown above ...
-    #     <name-reverse>slangis73</name-reverse>
-    #   </firm>
-    #
-    # To include deeper levels of associations pass a hash like this:
-    #
-    #   firm.to_xml include: {account: {}, clients: {include: :address}}
-    #   <?xml version="1.0" encoding="UTF-8"?>
-    #   <firm>
-    #     <id type="integer">1</id>
-    #     <rating type="integer">1</rating>
-    #     <name>37signals</name>
-    #     <clients type="array">
-    #       <client>
-    #         <rating type="integer">1</rating>
-    #         <name>Summit</name>
-    #         <address>
-    #           ...
-    #         </address>
-    #       </client>
-    #       <client>
-    #         <rating type="integer">1</rating>
-    #         <name>Microsoft</name>
-    #         <address>
-    #           ...
-    #         </address>
-    #       </client>
-    #     </clients>
-    #     <account>
-    #       <id type="integer">1</id>
-    #       <credit-limit type="integer">50</credit-limit>
-    #     </account>
-    #   </firm>
-    #
-    # To include any methods on the model being called use <tt>:methods</tt>:
-    #
-    #   firm.to_xml methods: [ :calculated_earnings, :real_earnings ]
-    #
-    #   <firm>
-    #     # ... normal attributes as shown above ...
-    #     <calculated-earnings>100000000000000000</calculated-earnings>
-    #     <real-earnings>5</real-earnings>
-    #   </firm>
-    #
-    # To call any additional Procs use <tt>:procs</tt>. The Procs are passed a
-    # modified version of the options hash that was given to +to_xml+:
-    #
-    #   proc = Proc.new { |options| options[:builder].tag!('abc', 'def') }
-    #   firm.to_xml procs: [ proc ]
-    #
-    #   <firm>
-    #     # ... normal attributes as shown above ...
-    #     <abc>def</abc>
-    #   </firm>
-    #
-    # Alternatively, you can yield the builder object as part of the +to_xml+ call:
-    #
-    #   firm.to_xml do |xml|
-    #     xml.creator do
-    #       xml.first_name "David"
-    #       xml.last_name "Heinemeier Hansson"
-    #     end
-    #   end
-    #
-    #   <firm>
-    #     # ... normal attributes as shown above ...
-    #     <creator>
-    #       <first_name>David</first_name>
-    #       <last_name>Heinemeier Hansson</last_name>
-    #     </creator>
-    #   </firm>
-    #
-    # As noted above, you may override +to_xml+ in your ActiveRecord::Base
-    # subclasses to have complete control about what's generated. The general
-    # form of doing this is:
-    #
-    #   class IHaveMyOwnXML < ActiveRecord::Base
-    #     def to_xml(options = {})
-    #       require 'builder'
-    #       options[:indent] ||= 2
-    #       xml = options[:builder] ||= ::Builder::XmlMarkup.new(indent: options[:indent])
-    #       xml.instruct! unless options[:skip_instruct]
-    #       xml.level_one do
-    #         xml.tag!(:second_level, 'content')
-    #       end
-    #     end
-    #   end
-    def to_xml(options = {}, &block)
-      XmlSerializer.new(self, options).serialize(&block)
-    end
-  end
-
-  class XmlSerializer < ActiveModel::Serializers::Xml::Serializer #:nodoc:
-    class Attribute < ActiveModel::Serializers::Xml::Serializer::Attribute #:nodoc:
-      def compute_type
-        klass = @serializable.class
-        cast_type = klass.type_for_attribute(name)
-
-        type = ActiveSupport::XmlMini::TYPE_NAMES[value.class.name] || cast_type.type
-
-        { :text => :string,
-          :time => :datetime }[type] || type
-      end
-      protected :compute_type
-    end
-  end
-end
diff --git a/activerecord/test/cases/serialization_test.rb b/activerecord/test/cases/serialization_test.rb
index 35b13ea247..14b80f4df4 100644
--- a/activerecord/test/cases/serialization_test.rb
+++ b/activerecord/test/cases/serialization_test.rb
@@ -8,7 +8,7 @@ require 'models/post'
 class SerializationTest < ActiveRecord::TestCase
   fixtures :books
 
-  FORMATS = [ :xml, :json ]
+  FORMATS = [ :json ]
 
   def setup
     @contact_attributes = {
diff --git a/activerecord/test/cases/xml_serialization_test.rb b/activerecord/test/cases/xml_serialization_test.rb
deleted file mode 100644
index b30b50f597..0000000000
--- a/activerecord/test/cases/xml_serialization_test.rb
+++ /dev/null
@@ -1,447 +0,0 @@
-require "cases/helper"
-require "rexml/document"
-require 'models/contact'
-require 'models/post'
-require 'models/author'
-require 'models/comment'
-require 'models/company_in_module'
-require 'models/toy'
-require 'models/topic'
-require 'models/reply'
-require 'models/company'
-
-class XmlSerializationTest < ActiveRecord::TestCase
-  def test_should_serialize_default_root
-    @xml = Contact.new.to_xml
-    assert_match %r{^<contact>},  @xml
-    assert_match %r{</contact>$}, @xml
-  end
-
-  def test_should_serialize_default_root_with_namespace
-    @xml = Contact.new.to_xml :namespace=>"http://xml.rubyonrails.org/contact"
-    assert_match %r{^<contact xmlns="http://xml\.rubyonrails\.org/contact">},  @xml
-    assert_match %r{</contact>$}, @xml
-  end
-
-  def test_should_serialize_custom_root
-    @xml = Contact.new.to_xml :root => 'xml_contact'
-    assert_match %r{^<xml-contact>},  @xml
-    assert_match %r{</xml-contact>$}, @xml
-  end
-
-  def test_should_allow_undasherized_tags
-    @xml = Contact.new.to_xml :root => 'xml_contact', :dasherize => false
-    assert_match %r{^<xml_contact>},  @xml
-    assert_match %r{</xml_contact>$}, @xml
-    assert_match %r{<created_at},     @xml
-  end
-
-  def test_should_allow_camelized_tags
-    @xml = Contact.new.to_xml :root => 'xml_contact', :camelize => true
-    assert_match %r{^<XmlContact>},  @xml
-    assert_match %r{</XmlContact>$}, @xml
-    assert_match %r{<CreatedAt},    @xml
-  end
-
-  def test_should_allow_skipped_types
-    @xml = Contact.new(:age => 25).to_xml :skip_types => true
-    assert %r{<age>25</age>}.match(@xml)
-  end
-
-  def test_should_include_yielded_additions
-    @xml = Contact.new.to_xml do |xml|
-      xml.creator "David"
-    end
-    assert_match %r{<creator>David</creator>}, @xml
-  end
-
-  def test_to_xml_with_block
-    value = "Rockin' the block"
-    xml = Contact.new.to_xml(:skip_instruct => true) do |_xml|
-      _xml.tag! "arbitrary-element", value
-    end
-    assert_equal "<contact>", xml.first(9)
-    assert xml.include?(%(<arbitrary-element>#{value}</arbitrary-element>))
-  end
-
-  def test_should_skip_instruct_for_included_records
-    @contact = Contact.new
-    @contact.alternative = Contact.new(:name => 'Copa Cabana')
-    @xml = @contact.to_xml(:include => [ :alternative ])
-    assert_equal @xml.index('<?xml '), 0
-    assert_nil @xml.index('<?xml ', 1)
-  end
-end
-
-class DefaultXmlSerializationTest < ActiveRecord::TestCase
-  def setup
-    @contact = Contact.new(
-      :name        => 'aaron stack',
-      :age         => 25,
-      :avatar      => 'binarydata',
-      :created_at  => Time.utc(2006, 8, 1),
-      :awesome     => false,
-      :preferences => { :gem => 'ruby' }
-    )
-  end
-
-  def test_should_serialize_string
-    assert_match %r{<name>aaron stack</name>}, @contact.to_xml
-  end
-
-  def test_should_serialize_integer
-    assert_match %r{<age type="integer">25</age>}, @contact.to_xml
-  end
-
-  def test_should_serialize_binary
-    xml = @contact.to_xml
-    assert_match %r{YmluYXJ5ZGF0YQ==\n</avatar>},    xml
-    assert_match %r{<avatar(.*)(type="binary")},     xml
-    assert_match %r{<avatar(.*)(encoding="base64")}, xml
-  end
-
-  def test_should_serialize_datetime
-    assert_match %r{<created-at type=\"dateTime\">2006-08-01T00:00:00Z</created-at>}, @contact.to_xml
-  end
-
-  def test_should_serialize_boolean
-    assert_match %r{<awesome type=\"boolean\">false</awesome>}, @contact.to_xml
-  end
-
-  def test_should_serialize_hash
-    assert_match %r{<preferences>\s*<gem>ruby</gem>\s*</preferences>}m, @contact.to_xml
-  end
-
-  def test_uses_serializable_hash_with_only_option
-    def @contact.serializable_hash(options=nil)
-      super(only: %w(name))
-    end
-
-    xml = @contact.to_xml
-    assert_match %r{<name>aaron stack</name>}, xml
-    assert_no_match %r{age}, xml
-    assert_no_match %r{awesome}, xml
-  end
-
-  def test_uses_serializable_hash_with_except_option
-    def @contact.serializable_hash(options=nil)
-      super(except: %w(age))
-    end
-
-    xml = @contact.to_xml
-    assert_match %r{<name>aaron stack</name>}, xml
-    assert_match %r{<awesome type=\"boolean\">false</awesome>}, xml
-    assert_no_match %r{age}, xml
-  end
-
-  def test_does_not_include_inheritance_column_from_sti
-    @contact = ContactSti.new(@contact.attributes)
-    assert_equal 'ContactSti', @contact.type
-
-    xml = @contact.to_xml
-    assert_match %r{<name>aaron stack</name>}, xml
-    assert_no_match %r{<type}, xml
-    assert_no_match %r{ContactSti}, xml
-  end
-
-  def test_serializable_hash_with_default_except_option_and_excluding_inheritance_column_from_sti
-    @contact = ContactSti.new(@contact.attributes)
-    assert_equal 'ContactSti', @contact.type
-
-    def @contact.serializable_hash(options={})
-      super({ except: %w(age) }.merge!(options))
-    end
-
-    xml = @contact.to_xml
-    assert_match %r{<name>aaron stack</name>}, xml
-    assert_no_match %r{age}, xml
-    assert_no_match %r{<type}, xml
-    assert_no_match %r{ContactSti}, xml
-  end
-end
-
-class DefaultXmlSerializationTimezoneTest < ActiveRecord::TestCase
-  def test_should_serialize_datetime_with_timezone
-    with_timezone_config zone: "Pacific Time (US & Canada)" do
-      toy = Toy.create(:name => 'Mickey', :updated_at => Time.utc(2006, 8, 1))
-      assert_match %r{<updated-at type=\"dateTime\">2006-07-31T17:00:00-07:00</updated-at>}, toy.to_xml
-    end
-  end
-
-  def test_should_serialize_datetime_with_timezone_reloaded
-    with_timezone_config zone: "Pacific Time (US & Canada)" do
-      toy = Toy.create(:name => 'Minnie', :updated_at => Time.utc(2006, 8, 1)).reload
-      assert_match %r{<updated-at type=\"dateTime\">2006-07-31T17:00:00-07:00</updated-at>}, toy.to_xml
-    end
-  end
-end
-
-class NilXmlSerializationTest < ActiveRecord::TestCase
-  def setup
-    @xml = Contact.new.to_xml(:root => 'xml_contact')
-  end
-
-  def test_should_serialize_string
-    assert_match %r{<name nil="true"/>}, @xml
-  end
-
-  def test_should_serialize_integer
-    assert %r{<age (.*)/>}.match(@xml)
-    attributes = $1
-    assert_match %r{nil="true"}, attributes
-    assert_match %r{type="integer"}, attributes
-  end
-
-  def test_should_serialize_binary
-    assert %r{<avatar (.*)/>}.match(@xml)
-    attributes = $1
-    assert_match %r{type="binary"}, attributes
-    assert_match %r{encoding="base64"}, attributes
-    assert_match %r{nil="true"}, attributes
-  end
-
-  def test_should_serialize_datetime
-    assert %r{<created-at (.*)/>}.match(@xml)
-    attributes = $1
-    assert_match %r{nil="true"}, attributes
-    assert_match %r{type="dateTime"}, attributes
-  end
-
-  def test_should_serialize_boolean
-    assert %r{<awesome (.*)/>}.match(@xml)
-    attributes = $1
-    assert_match %r{type="boolean"}, attributes
-    assert_match %r{nil="true"}, attributes
-  end
-
-  def test_should_serialize_yaml
-    assert_match %r{<preferences nil=\"true\"/>}, @xml
-  end
-end
-
-class DatabaseConnectedXmlSerializationTest < ActiveRecord::TestCase
-  fixtures :topics, :companies, :accounts, :authors, :posts, :projects
-
-  def test_to_xml
-    xml = REXML::Document.new(topics(:first).to_xml(:indent => 0))
-    bonus_time_in_current_timezone = topics(:first).bonus_time.xmlschema
-    written_on_in_current_timezone = topics(:first).written_on.xmlschema
-
-    assert_equal "topic", xml.root.name
-    assert_equal "The First Topic" , xml.elements["//title"].text
-    assert_equal "David" , xml.elements["//author-name"].text
-    assert_match "Have a nice day", xml.elements["//content"].text
-
-    assert_equal "1", xml.elements["//id"].text
-    assert_equal "integer" , xml.elements["//id"].attributes['type']
-
-    assert_equal "1", xml.elements["//replies-count"].text
-    assert_equal "integer" , xml.elements["//replies-count"].attributes['type']
-
-    assert_equal written_on_in_current_timezone, xml.elements["//written-on"].text
-    assert_equal "dateTime" , xml.elements["//written-on"].attributes['type']
-
-    assert_equal "david@loudthinking.com", xml.elements["//author-email-address"].text
-
-    assert_equal nil, xml.elements["//parent-id"].text
-    assert_equal "integer", xml.elements["//parent-id"].attributes['type']
-    assert_equal "true", xml.elements["//parent-id"].attributes['nil']
-
-    # Oracle enhanced adapter allows to define Date attributes in model class (see topic.rb)
-    assert_equal "2004-04-15", xml.elements["//last-read"].text
-    assert_equal "date" , xml.elements["//last-read"].attributes['type']
-
-    # Oracle and DB2 don't have true boolean or time-only fields
-    unless current_adapter?(:OracleAdapter, :DB2Adapter)
-      assert_equal "false", xml.elements["//approved"].text
-      assert_equal "boolean" , xml.elements["//approved"].attributes['type']
-
-      assert_equal bonus_time_in_current_timezone, xml.elements["//bonus-time"].text
-      assert_equal "dateTime" , xml.elements["//bonus-time"].attributes['type']
-    end
-  end
-
-  def test_except_option
-    xml = topics(:first).to_xml(:indent => 0, :skip_instruct => true, :except => [:title, :replies_count])
-    assert_equal "<topic>", xml.first(7)
-    assert !xml.include?(%(<title>The First Topic</title>))
-    assert xml.include?(%(<author-name>David</author-name>))
-
-    xml = topics(:first).to_xml(:indent => 0, :skip_instruct => true, :except => [:title, :author_name, :replies_count])
-    assert !xml.include?(%(<title>The First Topic</title>))
-    assert !xml.include?(%(<author-name>David</author-name>))
-  end
-
-  # to_xml used to mess with the hash the user provided which
-  # caused the builder to be reused.  This meant the document kept
-  # getting appended to.
-
-  def test_modules
-    projects = MyApplication::Business::Project.all
-    xml = projects.to_xml
-    root = projects.first.class.to_s.underscore.pluralize.tr('/','_').dasherize
-    assert_match "<#{root} type=\"array\">", xml
-    assert_match "</#{root}>", xml
-  end
-
-  def test_passing_hash_shouldnt_reuse_builder
-    options = {:include=>:posts}
-    david = authors(:david)
-    first_xml_size = david.to_xml(options).size
-    second_xml_size = david.to_xml(options).size
-    assert_equal first_xml_size, second_xml_size
-  end
-
-  def test_include_uses_association_name
-    xml = authors(:david).to_xml :include=>:hello_posts, :indent => 0
-    assert_match %r{<hello-posts type="array">}, xml
-    assert_match %r{<hello-post type="Post">}, xml
-    assert_match %r{<hello-post type="StiPost">}, xml
-  end
-
-  def test_included_associations_should_skip_types
-    xml = authors(:david).to_xml :include=>:hello_posts, :indent => 0, :skip_types => true
-    assert_match %r{<hello-posts>}, xml
-    assert_match %r{<hello-post>}, xml
-    assert_match %r{<hello-post>}, xml
-  end
-
-  def test_including_has_many_association
-    xml = topics(:first).to_xml(:indent => 0, :skip_instruct => true, :include => :replies, :except => :replies_count)
-    assert_equal "<topic>", xml.first(7)
-    assert xml.include?(%(<replies type="array"><reply>))
-    assert xml.include?(%(<title>The Second Topic of the day</title>))
-  end
-
-  def test_including_belongs_to_association
-    xml = companies(:first_client).to_xml(:indent => 0, :skip_instruct => true, :include => :firm)
-    assert !xml.include?("<firm>")
-
-    xml = companies(:second_client).to_xml(:indent => 0, :skip_instruct => true, :include => :firm)
-    assert xml.include?("<firm>")
-  end
-
-  def test_including_multiple_associations
-    xml = companies(:first_firm).to_xml(:indent => 0, :skip_instruct => true, :include => [ :clients, :account ])
-    assert_equal "<firm>", xml.first(6)
-    assert xml.include?(%(<account>))
-    assert xml.include?(%(<clients type="array"><client>))
-  end
-
-  def test_including_association_with_options
-    xml = companies(:first_firm).to_xml(
-      :indent  => 0, :skip_instruct => true,
-      :include => { :clients => { :only => :name } }
-    )
-
-    assert_equal "<firm>", xml.first(6)
-    assert xml.include?(%(<client><name>Summit</name></client>))
-    assert xml.include?(%(<clients type="array"><client>))
-  end
-
-  def test_methods_are_called_on_object
-    xml = authors(:david).to_xml :methods => :label, :indent => 0
-    assert_match %r{<label>.*</label>}, xml
-  end
-
-  def test_should_not_call_methods_on_associations_that_dont_respond
-    xml = authors(:david).to_xml :include=>:hello_posts, :methods => :label, :indent => 2
-    assert !authors(:david).hello_posts.first.respond_to?(:label)
-    assert_match %r{^  <label>.*</label>}, xml
-    assert_no_match %r{^      <label>}, xml
-  end
-
-  def test_procs_are_called_on_object
-    proc = Proc.new { |options| options[:builder].tag!('nationality', 'Danish') }
-    xml = authors(:david).to_xml(:procs => [ proc ])
-    assert_match %r{<nationality>Danish</nationality>}, xml
-  end
-
-  def test_dual_arity_procs_are_called_on_object
-    proc = Proc.new { |options, record| options[:builder].tag!('name-reverse', record.name.reverse) }
-    xml = authors(:david).to_xml(:procs => [ proc ])
-    assert_match %r{<name-reverse>divaD</name-reverse>}, xml
-  end
-
-  def test_top_level_procs_arent_applied_to_associations
-    author_proc = Proc.new { |options| options[:builder].tag!('nationality', 'Danish') }
-    xml = authors(:david).to_xml(:procs => [ author_proc ], :include => :posts, :indent => 2)
-
-    assert_match %r{^  <nationality>Danish</nationality>}, xml
-    assert_no_match %r{^ {6}<nationality>Danish</nationality>}, xml
-  end
-
-  def test_procs_on_included_associations_are_called
-    posts_proc = Proc.new { |options| options[:builder].tag!('copyright', 'DHH') }
-    xml = authors(:david).to_xml(
-      :indent => 2,
-      :include => {
-        :posts => { :procs => [ posts_proc ] }
-      }
-    )
-
-    assert_no_match %r{^  <copyright>DHH</copyright>}, xml
-    assert_match %r{^ {6}<copyright>DHH</copyright>}, xml
-  end
-
-  def test_should_include_empty_has_many_as_empty_array
-    authors(:david).posts.delete_all
-    xml = authors(:david).to_xml :include=>:posts, :indent => 2
-
-    assert_equal [], Hash.from_xml(xml)['author']['posts']
-    assert_match %r{^  <posts type="array"/>}, xml
-  end
-
-  def test_should_has_many_array_elements_should_include_type_when_different_from_guessed_value
-    xml = authors(:david).to_xml :include=>:posts_with_comments, :indent => 2
-
-    assert Hash.from_xml(xml)
-    assert_match %r{^  <posts-with-comments type="array">}, xml
-    assert_match %r{^    <posts-with-comment type="Post">}, xml
-    assert_match %r{^    <posts-with-comment type="StiPost">}, xml
-
-    types = Hash.from_xml(xml)['author']['posts_with_comments'].collect {|t| t['type'] }
-    assert types.include?('SpecialPost')
-    assert types.include?('Post')
-    assert types.include?('StiPost')
-  end
-
-  def test_should_produce_xml_for_methods_returning_array
-    xml = authors(:david).to_xml(:methods => :social)
-    array = Hash.from_xml(xml)['author']['social']
-    assert_equal 2, array.size
-    assert array.include? 'twitter'
-    assert array.include? 'github'
-  end
-
-  def test_should_support_aliased_attributes
-    xml = Author.select("name as firstname").to_xml
-    Author.all.each do |author|
-      assert xml.include?(%(<firstname>#{author.name}</firstname>)), xml
-    end
-  end
-
-  def test_array_to_xml_including_has_many_association
-    xml = [ topics(:first), topics(:second) ].to_xml(:indent => 0, :skip_instruct => true, :include => :replies)
-    assert xml.include?(%(<replies type="array"><reply>))
-  end
-
-  def test_array_to_xml_including_methods
-    xml = [ topics(:first), topics(:second) ].to_xml(:indent => 0, :skip_instruct => true, :methods => [ :topic_id ])
-    assert xml.include?(%(<topic-id type="integer">#{topics(:first).topic_id}</topic-id>)), xml
-    assert xml.include?(%(<topic-id type="integer">#{topics(:second).topic_id}</topic-id>)), xml
-  end
-
-  def test_array_to_xml_including_has_one_association
-    xml = [ companies(:first_firm), companies(:rails_core) ].to_xml(:indent => 0, :skip_instruct => true, :include => :account)
-    assert xml.include?(companies(:first_firm).account.to_xml(:indent => 0, :skip_instruct => true))
-    assert xml.include?(companies(:rails_core).account.to_xml(:indent => 0, :skip_instruct => true))
-  end
-
-  def test_array_to_xml_including_belongs_to_association
-    xml = [ companies(:first_client), companies(:second_client), companies(:another_client) ].to_xml(:indent => 0, :skip_instruct => true, :include => :firm)
-    assert xml.include?(companies(:first_client).to_xml(:indent => 0, :skip_instruct => true))
-    assert xml.include?(companies(:second_client).firm.to_xml(:indent => 0, :skip_instruct => true))
-    assert xml.include?(companies(:another_client).firm.to_xml(:indent => 0, :skip_instruct => true))
-  end
-end
diff --git a/guides/source/active_model_basics.md b/guides/source/active_model_basics.md
index 4b2bfaee2f..97180a8414 100644
--- a/guides/source/active_model_basics.md
+++ b/guides/source/active_model_basics.md
@@ -319,9 +319,8 @@ person.serializable_hash   # => {"name"=>"Bob"}
 
 #### ActiveModel::Serializers
 
-Rails provides two serializers `ActiveModel::Serializers::JSON` and
-`ActiveModel::Serializers::Xml`. Both of these modules automatically include
-the `ActiveModel::Serialization`.
+Rails provides a `ActiveModel::Serializers::JSON` serializer.
+This module automatically include the `ActiveModel::Serialization`.
 
 ##### ActiveModel::Serializers::JSON
 
@@ -379,62 +378,6 @@ person.from_json(json) # => #<Person:0x00000100c773f0 @name="Bob">
 person.name            # => "Bob"
 ```
 
-##### ActiveModel::Serializers::Xml
-
-To use the `ActiveModel::Serializers::Xml` you only need to change from
-`ActiveModel::Serialization` to `ActiveModel::Serializers::Xml`.
-
-```ruby
-class Person
-  include ActiveModel::Serializers::Xml
-
-  attr_accessor :name
-
-  def attributes
-    {'name' => nil}
-  end
-end
-```
-
-With the `to_xml` you have an XML representing the model.
-
-```ruby
-person = Person.new
-person.to_xml # => "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<person>\n  <name nil=\"true\"/>\n</person>\n"
-person.name = "Bob"
-person.to_xml # => "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<person>\n  <name>Bob</name>\n</person>\n"
-```
-
-From an XML string you define the attributes of the model.
-You need to have the `attributes=` method defined on your class:
-
-```ruby
-class Person
-  include ActiveModel::Serializers::Xml
-
-  attr_accessor :name
-
-  def attributes=(hash)
-    hash.each do |key, value|
-      send("#{key}=", value)
-    end
-  end
-
-  def attributes
-    {'name' => nil}
-  end
-end
-```
-
-Now it is possible to create an instance of person and set the attributes using `from_xml`.
-
-```ruby
-xml = { name: 'Bob' }.to_xml
-person = Person.new
-person.from_xml(xml) # => #<Person:0x00000100c773f0 @name="Bob">
-person.name          # => "Bob"
-```
-
 ### Translation
 
 `ActiveModel::Translation` provides integration between your object and the Rails