Remove IdentityMap

.travis.yml

@@ -5,7 +5,7 @@ rvm:
   - 1.9.3
 env:
   - "GEM=railties"
-  - "GEM=ap,am,amo,ares,as"
+  - "GEM=ap,am,amo,as"
   - "GEM=ar:mysql"
   - "GEM=ar:mysql2"
   - "GEM=ar:sqlite3"

activerecord/CHANGELOG.md

@@ -1,5 +1,16 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Remove IdentityMap
+
+    IdentityMap has never graduated to be an "enabled-by-default" feature, due
+    to some inconsistencies with associations, as described in this commit:
+
+       https://github.com/rails/rails/commit/302c912bf6bcd0fa200d964ec2dc4a44abe328a6
+
+    Hence the removal from the codebase, until such issues are fixed.
+
+    *Carlos Antonio da Silva*
+
 *   Added the schema cache dump feature.
 
     `Schema cache dump` feature was implemetend. This feature can dump/load internal state of `SchemaCache` instance

activerecord/RUNNING_UNIT_TESTS

@@ -26,13 +26,6 @@ You can run all the tests for a given database via rake:
 
 The 'rake test' task will run all the tests for mysql, mysql2, sqlite3 and postgresql.
 
-== Identity Map
-
-By default the tests run with the Identity Map turned off. But all tests should pass whether or
-not the identity map is on or off. You can turn it on using the IM env variable:
-
-  $ IM=true ruby -Itest test/case/base_test.rb
-
 == Config file
 
 By default, the config file is expected to be at the path test/config.yml. You can specify a

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

activerecord/lib/active_record/associations/association.rb

@@ -45,7 +45,6 @@ def aliased_table_name
       # 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 @@ def target_scope
       # 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

activerecord/lib/active_record/attribute_methods/dirty.rb

@@ -22,8 +22,6 @@ def save(*) #:nodoc:
         if status = super
           @previously_changed = changes
           @changed_attributes.clear
-        elsif IdentityMap.enabled?
-          IdentityMap.remove(self)
         end
         status
       end
@@ -34,9 +32,6 @@ def save!(*) #:nodoc:
           @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.

activerecord/lib/active_record/autosave_association.rb

@@ -328,7 +328,6 @@ def save_collection_association(reflection)
         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 @@ def save_collection_association(reflection)
 
             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

activerecord/lib/active_record/counter_cache.rb

@@ -69,8 +69,6 @@ def update_counters(id, counters)
         "#{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
 

activerecord/lib/active_record/fixtures.rb

@@ -796,9 +796,7 @@ def setup_fixture_accessors(fixture_names = nil)
                 @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

activerecord/lib/active_record/inheritance.rb

@@ -63,26 +63,9 @@ def sti_name
       # 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.

activerecord/lib/active_record/model.rb

@@ -60,7 +60,6 @@ def self.extend(*modules)
     include AttributeMethods
     include Callbacks, ActiveModel::Observing, Timestamp
     include Associations
-    include IdentityMap
     include ActiveModel::SecurePassword
     include AutosaveAssociation, NestedAttributes
     include Aggregations, Transactions, Reflection, Serialization, Store

activerecord/lib/active_record/persistence.rb

@@ -115,10 +115,7 @@ def save!(*)
     # 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 @@ def destroy
       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 @@ def reload(options = nil)
       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 @@ def create
       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

activerecord/lib/active_record/railtie.rb

@@ -53,11 +53,6 @@ class Railtie < Rails::Railtie
       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)