Remove IdentityMap

15 files changed, 10 insertions, 243 deletions

diff --git a/activerecord/lib/active_record.rb b/activerecord/lib/active_record.rb
index 73c8a06ab7..0cb0644bcf 100644
--- a/activerecord/lib/active_record.rb
+++ b/activerecord/lib/active_record.rb
@@ -65,7 +65,6 @@ module ActiveRecord
     autoload :DynamicFinderMatch
     autoload :DynamicScopeMatch
     autoload :Explain
-    autoload :IdentityMap
     autoload :Inheritance
     autoload :Integration
     autoload :Migration
diff --git a/activerecord/lib/active_record/associations/association.rb b/activerecord/lib/active_record/associations/association.rb
index 512c52338e..fb0ca15c23 100644
--- a/activerecord/lib/active_record/associations/association.rb
+++ b/activerecord/lib/active_record/associations/association.rb
@@ -45,7 +45,6 @@ module ActiveRecord
       # Resets the \loaded flag to +false+ and sets the \target to +nil+.
       def reset
         @loaded = false
-        IdentityMap.remove(target) if IdentityMap.enabled? && target
         @target = nil
       end
 
@@ -135,17 +134,7 @@ module ActiveRecord
       # ActiveRecord::RecordNotFound is rescued within the method, and it is
       # not reraised. The proxy is \reset and +nil+ is the return value.
       def load_target
-        if find_target?
-          begin
-            if IdentityMap.enabled? && association_class && association_class.respond_to?(:base_class)
-              @target = IdentityMap.get(association_class, owner[reflection.foreign_key])
-            end
-          rescue NameError
-            nil
-          ensure
-            @target ||= find_target
-          end
-        end
+        @target ||= find_target if find_target?
         loaded! unless loaded?
         target
       rescue ActiveRecord::RecordNotFound
diff --git a/activerecord/lib/active_record/attribute_methods/dirty.rb b/activerecord/lib/active_record/attribute_methods/dirty.rb
index 3a737e5b35..11c63591e3 100644
--- a/activerecord/lib/active_record/attribute_methods/dirty.rb
+++ b/activerecord/lib/active_record/attribute_methods/dirty.rb
@@ -22,8 +22,6 @@ module ActiveRecord
         if status = super
           @previously_changed = changes
           @changed_attributes.clear
-        elsif IdentityMap.enabled?
-          IdentityMap.remove(self)
         end
         status
       end
@@ -34,9 +32,6 @@ module ActiveRecord
           @previously_changed = changes
           @changed_attributes.clear
         end
-      rescue
-        IdentityMap.remove(self) if IdentityMap.enabled?
-        raise
       end
 
       # <tt>reload</tt> the record and clears changed attributes.
diff --git a/activerecord/lib/active_record/autosave_association.rb b/activerecord/lib/active_record/autosave_association.rb
index eb3ae7014e..be0af081d1 100644
--- a/activerecord/lib/active_record/autosave_association.rb
+++ b/activerecord/lib/active_record/autosave_association.rb
@@ -328,7 +328,6 @@ module ActiveRecord
         autosave = reflection.options[:autosave]
 
         if records = associated_records_to_validate_or_save(association, @new_record_before_save, autosave)
-          begin
           records.each do |record|
             next if record.destroyed?
 
@@ -348,11 +347,6 @@ module ActiveRecord
 
             raise ActiveRecord::Rollback unless saved
           end
-          rescue
-            records.each {|x| IdentityMap.remove(x) } if IdentityMap.enabled?
-            raise
-          end
-
         end
 
         # reconstruct the scope now that we know the owner's id
diff --git a/activerecord/lib/active_record/counter_cache.rb b/activerecord/lib/active_record/counter_cache.rb
index 8d5388e1f3..f52979ebd9 100644
--- a/activerecord/lib/active_record/counter_cache.rb
+++ b/activerecord/lib/active_record/counter_cache.rb
@@ -69,8 +69,6 @@ module ActiveRecord
         "#{quoted_column} = COALESCE(#{quoted_column}, 0) #{operator} #{value.abs}"
       end
 
-      IdentityMap.remove_by_id(symbolized_base_class, id) if IdentityMap.enabled?
-
       update_all(updates.join(', '), primary_key => id)
     end
 
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index b82d5b5621..5c42e8f719 100644
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -796,9 +796,7 @@ module ActiveRecord
                 @fixture_cache[fixture_name].delete(fixture) if force_reload
 
                 if @loaded_fixtures[fixture_name][fixture.to_s]
-                  ActiveRecord::IdentityMap.without do
-                    @fixture_cache[fixture_name][fixture] ||= @loaded_fixtures[fixture_name][fixture.to_s].find
-                  end
+                  @fixture_cache[fixture_name][fixture] ||= @loaded_fixtures[fixture_name][fixture.to_s].find
                 else
                   raise StandardError, "No entry named '#{fixture}' found for fixture collection '#{fixture_name}'"
                 end
diff --git a/activerecord/lib/active_record/identity_map.rb b/activerecord/lib/active_record/identity_map.rb
deleted file mode 100644
index d9777bb2f6..0000000000
--- a/activerecord/lib/active_record/identity_map.rb
+++ /dev/null
@@ -1,144 +0,0 @@
-module ActiveRecord
-  # = Active Record Identity Map
-  #
-  # Ensures that each object gets loaded only once by keeping every loaded
-  # object in a map. Looks up objects using the map when referring to them.
-  #
-  # More information on Identity Map pattern:
-  #   http://www.martinfowler.com/eaaCatalog/identityMap.html
-  #
-  # == Configuration
-  #
-  # In order to enable IdentityMap, set <tt>config.active_record.identity_map = true</tt>
-  # in your <tt>config/application.rb</tt> file.
-  #
-  # IdentityMap is disabled by default and still in development (i.e. use it with care).
-  #
-  # == Associations
-  #
-  # Active Record Identity Map does not track associations yet. For example:
-  #
-  #   comment = @post.comments.first
-  #   comment.post = nil
-  #   @post.comments.include?(comment) #=> true
-  #
-  # Ideally, the example above would return false, removing the comment object from the
-  # post association when the association is nullified. This may cause side effects, as
-  # in the situation below, if Identity Map is enabled:
-  #
-  #   Post.has_many :comments, :dependent => :destroy
-  #
-  #   comment = @post.comments.first
-  #   comment.post = nil
-  #   comment.save
-  #   Post.destroy(@post.id)
-  #
-  # Without using Identity Map, the code above will destroy the @post object leaving
-  # the comment object intact. However, once we enable Identity Map, the post loaded
-  # by Post.destroy is exactly the same object as the object @post. As the object @post
-  # still has the comment object in @post.comments, once Identity Map is enabled, the
-  # comment object will be accidently removed.
-  #
-  # This inconsistency is meant to be fixed in future Rails releases.
-  #
-  module IdentityMap
-
-    class << self
-      def enabled=(flag)
-        Thread.current[:identity_map_enabled] = flag
-      end
-
-      def enabled
-        Thread.current[:identity_map_enabled]
-      end
-      alias enabled? enabled
-
-      def repository
-        Thread.current[:identity_map] ||= Hash.new { |h,k| h[k] = {} }
-      end
-
-      def use
-        old, self.enabled = enabled, true
-
-        yield if block_given?
-      ensure
-        self.enabled = old
-        clear
-      end
-
-      def without
-        old, self.enabled = enabled, false
-
-        yield if block_given?
-      ensure
-        self.enabled = old
-      end
-
-      def get(klass, primary_key)
-        record = repository[klass.symbolized_sti_name][primary_key]
-
-        if record.is_a?(klass)
-          ActiveSupport::Notifications.instrument("identity.active_record",
-            :line => "From Identity Map (id: #{primary_key})",
-            :name => "#{klass} Loaded",
-            :connection_id => object_id)
-
-          record
-        else
-          nil
-        end
-      end
-
-      def add(record)
-        repository[record.class.symbolized_sti_name][record.id] = record
-      end
-
-      def remove(record)
-        repository[record.class.symbolized_sti_name].delete(record.id)
-      end
-
-      def remove_by_id(symbolized_sti_name, id)
-        repository[symbolized_sti_name].delete(id)
-      end
-
-      def clear
-        repository.clear
-      end
-    end
-
-    # Reinitialize an Identity Map model object from +coder+.
-    # +coder+ must contain the attributes necessary for initializing an empty
-    # model object.
-    def reinit_with(coder)
-      @attributes_cache = {}
-      dirty      = @changed_attributes.keys
-      attributes = self.class.initialize_attributes(coder['attributes'].except(*dirty))
-      @attributes.update(attributes)
-      @changed_attributes.update(coder['attributes'].slice(*dirty))
-      @changed_attributes.delete_if{|k,v| v.eql? @attributes[k]}
-
-      run_callbacks :find
-
-      self
-    end
-
-    class Middleware
-      def initialize(app)
-        @app = app
-      end
-
-      def call(env)
-        enabled = IdentityMap.enabled
-        IdentityMap.enabled = true
-
-        response = @app.call(env)
-        response[2] = Rack::BodyProxy.new(response[2]) do
-          IdentityMap.enabled = enabled
-          IdentityMap.clear
-        end
-
-        response
-      end
-    end
-  end
-end
diff --git a/activerecord/lib/active_record/inheritance.rb b/activerecord/lib/active_record/inheritance.rb
index 2c766411a0..ebe244c6a6 100644
--- a/activerecord/lib/active_record/inheritance.rb
+++ b/activerecord/lib/active_record/inheritance.rb
@@ -63,26 +63,9 @@ module ActiveRecord
       # single-table inheritance model that makes it possible to create
       # objects of different types from the same table.
       def instantiate(record, column_types = {})
-        sti_class = find_sti_class(record[inheritance_column])
-        record_id = sti_class.primary_key && record[sti_class.primary_key]
-
-        if ActiveRecord::IdentityMap.enabled? && record_id
-          if (column = sti_class.columns_hash[sti_class.primary_key]) && column.number?
-            record_id = record_id.to_i
-          end
-          if instance = IdentityMap.get(sti_class, record_id)
-            instance.reinit_with('attributes' => record)
-          else
-            instance = sti_class.allocate.init_with('attributes' => record)
-            IdentityMap.add(instance)
-          end
-        else
-          column_types = sti_class.decorate_columns(column_types)
-          instance = sti_class.allocate.init_with('attributes' => record,
-                                                  'column_types' => column_types)
-        end
-
-        instance
+        sti_class    = find_sti_class(record[inheritance_column])
+        column_types = sti_class.decorate_columns(column_types)
+        sti_class.allocate.init_with('attributes' => record, 'column_types' => column_types)
       end
 
       # For internal use.
diff --git a/activerecord/lib/active_record/model.rb b/activerecord/lib/active_record/model.rb
index 86de5ab2fa..105d1e0e2b 100644
--- a/activerecord/lib/active_record/model.rb
+++ b/activerecord/lib/active_record/model.rb
@@ -60,7 +60,6 @@ module ActiveRecord
     include AttributeMethods
     include Callbacks, ActiveModel::Observing, Timestamp
     include Associations
-    include IdentityMap
     include ActiveModel::SecurePassword
     include AutosaveAssociation, NestedAttributes
     include Aggregations, Transactions, Reflection, Serialization, Store
diff --git a/activerecord/lib/active_record/persistence.rb b/activerecord/lib/active_record/persistence.rb
index 09502bb52c..35c922e979 100644
--- a/activerecord/lib/active_record/persistence.rb
+++ b/activerecord/lib/active_record/persistence.rb
@@ -115,10 +115,7 @@ module ActiveRecord
     # callbacks, Observer methods, or any <tt>:dependent</tt> association
     # options, use <tt>#destroy</tt>.
     def delete
-      if persisted?
-        self.class.delete(id)
-        IdentityMap.remove(self) if IdentityMap.enabled?
-      end
+      self.class.delete(id) if persisted?
       @destroyed = true
       freeze
     end
@@ -129,7 +126,6 @@ module ActiveRecord
       destroy_associations
 
       if persisted?
-        IdentityMap.remove(self) if IdentityMap.enabled?
         pk         = self.class.primary_key
         column     = self.class.columns_hash[pk]
         substitute = connection.substitute_at(column, 0)
@@ -284,11 +280,9 @@ module ActiveRecord
       clear_aggregation_cache
       clear_association_cache
 
-      IdentityMap.without do
-        fresh_object = self.class.unscoped { self.class.find(id, options) }
-        @attributes.update(fresh_object.instance_variable_get('@attributes'))
-        @columns_hash = fresh_object.instance_variable_get('@columns_hash')
-      end
+      fresh_object = self.class.unscoped { self.class.find(id, options) }
+      @attributes.update(fresh_object.instance_variable_get('@attributes'))
+      @columns_hash = fresh_object.instance_variable_get('@columns_hash')
 
       @attributes_cache = {}
       self
@@ -363,10 +357,8 @@ module ActiveRecord
       attributes_values = arel_attributes_with_values_for_create(!id.nil?)
 
       new_id = self.class.unscoped.insert attributes_values
-
       self.id ||= new_id if self.class.primary_key
 
-      IdentityMap.add(self) if IdentityMap.enabled?
       @new_record = false
       id
     end
diff --git a/activerecord/lib/active_record/railtie.rb b/activerecord/lib/active_record/railtie.rb
index 516c450f85..ee3a6bf8c0 100644
--- a/activerecord/lib/active_record/railtie.rb
+++ b/activerecord/lib/active_record/railtie.rb
@@ -53,11 +53,6 @@ module ActiveRecord
       ActiveSupport.on_load(:active_record) { self.logger ||= ::Rails.logger }
     end
 
-    initializer "active_record.identity_map" do |app|
-      config.app_middleware.insert_after "::ActionDispatch::Callbacks",
-        "ActiveRecord::IdentityMap::Middleware" if config.active_record.delete(:identity_map)
-    end
-
     initializer "active_record.set_configs" do |app|
       ActiveSupport.on_load(:active_record) do
         if app.config.active_record.delete(:whitelist_attributes)
diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb
index 7531e1fe6f..6f39708ec3 100644
--- a/activerecord/lib/active_record/relation.rb
+++ b/activerecord/lib/active_record/relation.rb
@@ -168,13 +168,7 @@ module ActiveRecord
       default_scoped = with_default_scope
 
       if default_scoped.equal?(self)
-        @records = if @readonly_value.nil? && !@klass.locking_enabled?
-          eager_loading? ? find_with_associations : @klass.find_by_sql(arel, @bind_values)
-        else
-          IdentityMap.without do
-            eager_loading? ? find_with_associations : @klass.find_by_sql(arel, @bind_values)
-          end
-        end
+        @records = eager_loading? ? find_with_associations : @klass.find_by_sql(arel, @bind_values)
 
         preload = @preload_values
         preload +=  @includes_values unless eager_loading?
@@ -274,7 +268,6 @@ module ActiveRecord
     #   # The same idea applies to limit and order
     #   Book.where('title LIKE ?', '%Rails%').order(:created_at).limit(5).update_all(:author => 'David')
     def update_all(updates, conditions = nil, options = {})
-      IdentityMap.repository[symbolized_base_class].clear if IdentityMap.enabled?
       if conditions || options.present?
         where(conditions).apply_finder_options(options.slice(:limit, :order)).update_all(updates)
       else
@@ -404,7 +397,6 @@ module ActiveRecord
     # If you need to destroy dependent associations or call your <tt>before_*</tt> or
     # +after_destroy+ callbacks, use the +destroy_all+ method instead.
     def delete_all(conditions = nil)
-      IdentityMap.repository[symbolized_base_class] = {} if IdentityMap.enabled?
       if conditions
         where(conditions).delete_all
       else
@@ -437,7 +429,6 @@ module ActiveRecord
     #   # Delete multiple rows
     #   Todo.delete([2,3,4])
     def delete(id_or_array)
-      IdentityMap.remove_by_id(self.symbolized_base_class, id_or_array) if IdentityMap.enabled?
       where(primary_key => id_or_array).delete_all
     end
 
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index adfacf37ee..52e67ecc6e 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -318,17 +318,7 @@ module ActiveRecord
     def find_one(id)
       id = id.id if ActiveRecord::Base === id
 
-      if IdentityMap.enabled? && where_values.blank? &&
-        limit_value.blank? && order_values.blank? &&
-        includes_values.blank? && preload_values.blank? &&
-        readonly_value.nil? && joins_values.blank? &&
-        !@klass.locking_enabled? &&
-        record = IdentityMap.get(@klass, id)
-        return record
-      end
-
       column = columns_hash[primary_key]
-
       substitute = connection.substitute_at(column, @bind_values.length)
       relation = where(table[primary_key].eq(substitute))
       relation.bind_values += [[column, id]]
diff --git a/activerecord/lib/active_record/test_case.rb b/activerecord/lib/active_record/test_case.rb
index 4d881f0f7d..fcaa4b74a6 100644
--- a/activerecord/lib/active_record/test_case.rb
+++ b/activerecord/lib/active_record/test_case.rb
@@ -7,20 +7,10 @@ module ActiveRecord
   #
   # Defines some test assertions to test against SQL queries.
   class TestCase < ActiveSupport::TestCase #:nodoc:
-    setup :cleanup_identity_map
-
-    def setup
-      cleanup_identity_map
-    end
-
     def teardown
       SQLCounter.log.clear
     end
 
-    def cleanup_identity_map
-      ActiveRecord::IdentityMap.clear
-    end
-
     def assert_date_from_db(expected, actual, message = nil)
       # SybaseAdapter doesn't have a separate column type just for dates,
       # so the time is in the string and incorrectly formatted
diff --git a/activerecord/lib/active_record/transactions.rb b/activerecord/lib/active_record/transactions.rb
index b492377d18..743dfc5a38 100644
--- a/activerecord/lib/active_record/transactions.rb
+++ b/activerecord/lib/active_record/transactions.rb
@@ -251,7 +251,6 @@ module ActiveRecord
       remember_transaction_record_state
       yield
     rescue Exception
-      IdentityMap.remove(self) if IdentityMap.enabled?
       restore_transaction_record_state
       raise
     ensure
@@ -270,7 +269,6 @@ module ActiveRecord
     def rolledback!(force_restore_state = false) #:nodoc:
       run_callbacks :rollback
     ensure
-      IdentityMap.remove(self) if IdentityMap.enabled?
       restore_transaction_record_state(force_restore_state)
     end