Merge branch 'master' into nested_has_many_through

Conflicts:
	activerecord/lib/active_record/associations/has_many_through_association.rb
	activerecord/test/cases/associations/has_many_through_associations_test.rb

26 files changed, 132 insertions, 104 deletions

diff --git a/activerecord/lib/active_record/aggregations.rb b/activerecord/lib/active_record/aggregations.rb
index 16206c1056..8cd7389005 100644
--- a/activerecord/lib/active_record/aggregations.rb
+++ b/activerecord/lib/active_record/aggregations.rb
@@ -6,7 +6,7 @@ module ActiveRecord
     def clear_aggregation_cache #:nodoc:
       self.class.reflect_on_all_aggregations.to_a.each do |assoc|
         instance_variable_set "@#{assoc.name}", nil
-      end unless self.new_record?
+      end if self.persisted?
     end
 
     # Active Record implements aggregation through a macro-like class method called +composed_of+
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index 577a807e3c..e82cbd0aa6 100644
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -117,7 +117,7 @@ module ActiveRecord
     def clear_association_cache #:nodoc:
       self.class.reflect_on_all_associations.to_a.each do |assoc|
         instance_variable_set "@#{assoc.name}", nil
-      end unless self.new_record?
+      end if self.persisted?
     end
 
     private
diff --git a/activerecord/lib/active_record/associations/association_collection.rb b/activerecord/lib/active_record/associations/association_collection.rb
index 896e18af01..6090376bb8 100644
--- a/activerecord/lib/active_record/associations/association_collection.rb
+++ b/activerecord/lib/active_record/associations/association_collection.rb
@@ -75,6 +75,7 @@ module ActiveRecord
           find(:first, *args)
         else
           load_target unless loaded?
+          args = args[1..-1] if args.first.kind_of?(Hash) && args.first.empty?
           @target.first(*args)
         end
       end
@@ -120,13 +121,13 @@ module ActiveRecord
       # Since << flattens its argument list and inserts each record, +push+ and +concat+ behave identically.
       def <<(*records)
         result = true
-        load_target if @owner.new_record?
+        load_target unless @owner.persisted?
 
         transaction do
           flatten_deeper(records).each do |record|
             raise_on_type_mismatch(record)
             add_record_to_target_with_callbacks(record) do |r|
-              result &&= insert_record(record) unless @owner.new_record?
+              result &&= insert_record(record) if @owner.persisted?
             end
           end
         end
@@ -181,7 +182,7 @@ module ActiveRecord
           unless options.blank?
             raise ArgumentError, "If finder_sql/counter_sql is used then options cannot be passed"
           end
-          
+
           @reflection.klass.count_by_sql(custom_counter_sql)
         else
 
@@ -285,12 +286,12 @@ module ActiveRecord
       # This method is abstract in the sense that it relies on
       # +count_records+, which is a method descendants have to provide.
       def size
-        if @owner.new_record? || (loaded? && !@reflection.options[:uniq])
+        if !@owner.persisted? || (loaded? && !@reflection.options[:uniq])
           @target.size
         elsif !loaded? && @reflection.options[:group]
           load_target.size
         elsif !loaded? && !@reflection.options[:uniq] && @target.is_a?(Array)
-          unsaved_records = @target.select { |r| r.new_record? }
+          unsaved_records = @target.reject { |r| r.persisted? }
           unsaved_records.size + count_records
         else
           count_records
@@ -331,13 +332,10 @@ module ActiveRecord
       end
 
       def uniq(collection = self)
-        seen = Set.new
-        collection.map do |record|
-          unless seen.include?(record.id)
-            seen << record.id
-            record
-          end
-        end.compact
+        seen = {}
+        collection.find_all do |record|
+          seen[record.id] = true unless seen.key?(record.id)
+        end
       end
 
       # Replace this collection with +other_array+
@@ -357,7 +355,7 @@ module ActiveRecord
 
       def include?(record)
         return false unless record.is_a?(@reflection.klass)
-        return include_in_memory?(record) if record.new_record?
+        return include_in_memory?(record) unless record.persisted?
         load_target if @reflection.options[:finder_sql] && !loaded?
         return @target.include?(record) if loaded?
         exists?(record)
@@ -372,16 +370,18 @@ module ActiveRecord
         end
 
         def load_target
-          if !@owner.new_record? || foreign_key_present
+          if @owner.persisted? || foreign_key_present
             begin
-              if !loaded?
+              unless loaded?
                 if @target.is_a?(Array) && @target.any?
                   @target = find_target.map do |f|
                     i = @target.index(f)
                     if i
                       @target.delete_at(i).tap do |t|
                         keys = ["id"] + t.changes.keys + (f.attribute_names - t.attribute_names)
-                        t.attributes = f.attributes.except(*keys)
+                        f.attributes.except(*keys).each do |k,v|
+                          t.send("#{k}=", v)
+                        end
                       end
                     else
                       f
@@ -408,11 +408,7 @@ module ActiveRecord
           end
 
           if @target.respond_to?(method) || (!@reflection.klass.respond_to?(method) && Class.respond_to?(method))
-            if block_given?
-              super { |*block_args| yield(*block_args) }
-            else
-              super
-            end
+            super
           elsif @reflection.klass.scopes[method]
             @_named_scopes_cache ||= {}
             @_named_scopes_cache[method] ||= {}
@@ -435,10 +431,10 @@ module ActiveRecord
             # replace the SELECT clause with COUNT(*), preserving any hints within /* ... */
             counter_sql = @reflection.options[:finder_sql].sub(/SELECT\b(\/\*.*?\*\/ )?(.*)\bFROM\b/im) { "SELECT #{$1}COUNT(*) FROM" }
           end
-          
+
           interpolate_sql(counter_sql)
         end
-        
+
         def custom_finder_sql
           interpolate_sql(@reflection.options[:finder_sql])
         end
@@ -513,7 +509,7 @@ module ActiveRecord
 
           transaction do
             records.each { |record| callback(:before_remove, record) }
-            old_records = records.reject { |r| r.new_record? }
+            old_records = records.select { |r| r.persisted? }
             yield(records, old_records)
             records.each { |record| callback(:after_remove, record) }
           end
@@ -538,14 +534,14 @@ module ActiveRecord
         end
 
         def ensure_owner_is_not_new
-          if @owner.new_record?
+          unless @owner.persisted?
             raise ActiveRecord::RecordNotSaved, "You cannot call create unless the parent is saved"
           end
         end
 
         def fetch_first_or_last_using_find?(args)
-          args.first.kind_of?(Hash) || !(loaded? || @owner.new_record? || @reflection.options[:finder_sql] ||
-                                         @target.any? { |record| record.new_record? } || args.first.kind_of?(Integer))
+          (args.first.kind_of?(Hash) && !args.first.empty?) || !(loaded? || !@owner.persisted? || @reflection.options[:finder_sql] ||
+                                         !@target.all? { |record| record.persisted? } || args.first.kind_of?(Integer))
         end
 
         def include_in_memory?(record)
diff --git a/activerecord/lib/active_record/associations/association_proxy.rb b/activerecord/lib/active_record/associations/association_proxy.rb
index ac2aa46edf..7cd04a1ad5 100644
--- a/activerecord/lib/active_record/associations/association_proxy.rb
+++ b/activerecord/lib/active_record/associations/association_proxy.rb
@@ -175,10 +175,10 @@ module ActiveRecord
         # If the association is polymorphic the type of the owner is also set.
         def set_belongs_to_association_for(record)
           if @reflection.options[:as]
-            record["#{@reflection.options[:as]}_id"]   = @owner.id unless @owner.new_record?
+            record["#{@reflection.options[:as]}_id"]   = @owner.id if @owner.persisted?
             record["#{@reflection.options[:as]}_type"] = @owner.class.base_class.name.to_s
           else
-            unless @owner.new_record?
+            if @owner.persisted?
               primary_key = @reflection.options[:primary_key] || :id
               record[@reflection.primary_key_name] = @owner.send(primary_key)
             end
@@ -211,12 +211,12 @@ module ActiveRecord
             :create => construct_create_scope
           }
         end
-        
+
         # Implemented by subclasses
         def construct_find_scope
           raise NotImplementedError
         end
-        
+
         # Implemented by (some) subclasses
         def construct_create_scope
           {}
@@ -252,7 +252,7 @@ module ActiveRecord
         def load_target
           return nil unless defined?(@loaded)
 
-          if !loaded? and (!@owner.new_record? || foreign_key_present)
+          if !loaded? and (@owner.persisted? || foreign_key_present)
             @target = find_target
           end
 
diff --git a/activerecord/lib/active_record/associations/belongs_to_association.rb b/activerecord/lib/active_record/associations/belongs_to_association.rb
index 34b6cd5576..b624951cd9 100644
--- a/activerecord/lib/active_record/associations/belongs_to_association.rb
+++ b/activerecord/lib/active_record/associations/belongs_to_association.rb
@@ -14,7 +14,7 @@ module ActiveRecord
         counter_cache_name = @reflection.counter_cache_column
 
         if record.nil?
-          if counter_cache_name && !@owner.new_record?
+          if counter_cache_name && @owner.persisted?
             @reflection.klass.decrement_counter(counter_cache_name, previous_record_id) if @owner[@reflection.primary_key_name]
           end
 
@@ -22,13 +22,13 @@ module ActiveRecord
         else
           raise_on_type_mismatch(record)
 
-          if counter_cache_name && !@owner.new_record? && record.id != @owner[@reflection.primary_key_name]
+          if counter_cache_name && @owner.persisted? && record.id != @owner[@reflection.primary_key_name]
             @reflection.klass.increment_counter(counter_cache_name, record.id)
             @reflection.klass.decrement_counter(counter_cache_name, @owner[@reflection.primary_key_name]) if @owner[@reflection.primary_key_name]
           end
 
           @target = (AssociationProxy === record ? record.target : record)
-          @owner[@reflection.primary_key_name] = record_id(record) unless record.new_record?
+          @owner[@reflection.primary_key_name] = record_id(record) if record.persisted?
           @updated = true
         end
 
diff --git a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
index 1fc9aba5cf..da742fa668 100644
--- a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
@@ -34,7 +34,7 @@ module ActiveRecord
         end
 
         def insert_record(record, force = true, validate = true)
-          if record.new_record?
+          unless record.persisted?
             if force
               record.save!
             else
diff --git a/activerecord/lib/active_record/associations/has_many_through_association.rb b/activerecord/lib/active_record/associations/has_many_through_association.rb
index c45f2ee224..c1fc16b0ed 100644
--- a/activerecord/lib/active_record/associations/has_many_through_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_through_association.rb
@@ -67,7 +67,7 @@ module ActiveRecord
         def insert_record(record, force = true, validate = true)
           ensure_not_nested
 
-          if record.new_record?
+          unless record.persisted?
             if force
               record.save!
             else
@@ -76,8 +76,7 @@ module ActiveRecord
           end
 
           through_association = @owner.send(@reflection.through_reflection.name)
-          through_record = through_association.create!(construct_join_attributes(record))
-          through_association.proxy_target << through_record
+          through_association.create!(construct_join_attributes(record))
         end
 
         # TODO - add dependent option support
diff --git a/activerecord/lib/active_record/associations/has_one_association.rb b/activerecord/lib/active_record/associations/has_one_association.rb
index c6bcfec275..0ccf07f15e 100644
--- a/activerecord/lib/active_record/associations/has_one_association.rb
+++ b/activerecord/lib/active_record/associations/has_one_association.rb
@@ -30,18 +30,18 @@ module ActiveRecord
           if dependent? && !dont_save
             case @reflection.options[:dependent]
             when :delete
-              @target.delete unless @target.new_record?
+              @target.delete if @target.persisted?
               @owner.clear_association_cache
             when :destroy
-              @target.destroy unless @target.new_record?
+              @target.destroy if @target.persisted?
               @owner.clear_association_cache
             when :nullify
               @target[@reflection.primary_key_name] = nil
-              @target.save unless @owner.new_record? || @target.new_record?
+              @target.save if @owner.persisted? && @target.persisted?
             end
           else
             @target[@reflection.primary_key_name] = nil
-            @target.save unless @owner.new_record? || @target.new_record?
+            @target.save if @owner.persisted? && @target.persisted?
           end
         end
 
@@ -56,7 +56,7 @@ module ActiveRecord
         set_inverse_instance(obj, @owner)
         @loaded = true
 
-        unless @owner.new_record? or obj.nil? or dont_save
+        unless !@owner.persisted? or obj.nil? or dont_save
           return (obj.save ? self : false)
         else
           return (obj.nil? ? nil : self)
@@ -113,7 +113,7 @@ module ActiveRecord
           if replace_existing
             replace(record, true)
           else
-            record[@reflection.primary_key_name] = @owner.id unless @owner.new_record?
+            record[@reflection.primary_key_name] = @owner.id if @owner.persisted?
             self.target = record
             set_inverse_instance(record, @owner)
           end
diff --git a/activerecord/lib/active_record/associations/has_one_through_association.rb b/activerecord/lib/active_record/associations/has_one_through_association.rb
index e9dc32efd3..cfd4637e8e 100644
--- a/activerecord/lib/active_record/associations/has_one_through_association.rb
+++ b/activerecord/lib/active_record/associations/has_one_through_association.rb
@@ -23,7 +23,7 @@ module ActiveRecord
         if current_object
            new_value ? current_object.update_attributes(construct_join_attributes(new_value)) : current_object.destroy
         elsif new_value
-          if @owner.new_record?
+          unless @owner.persisted?
             self.target = new_value
             through_association = @owner.send(:association_instance_get, @reflection.through_reflection.name)
             through_association.build(construct_join_attributes(new_value))
diff --git a/activerecord/lib/active_record/attribute_methods/primary_key.rb b/activerecord/lib/active_record/attribute_methods/primary_key.rb
index 82d94b848a..75ae06f5e9 100644
--- a/activerecord/lib/active_record/attribute_methods/primary_key.rb
+++ b/activerecord/lib/active_record/attribute_methods/primary_key.rb
@@ -3,10 +3,11 @@ module ActiveRecord
     module PrimaryKey
       extend ActiveSupport::Concern
 
-      # Returns this record's primary key value wrapped in an Array
-      # or nil if the record is a new_record?
+      # Returns this record's primary key value wrapped in an Array or nil if
+      # the record is not persisted? or has just been destroyed.
       def to_key
-        new_record? ? nil : [ id ]
+        key = send(self.class.primary_key)
+        [key] if key
       end
 
       module ClassMethods
diff --git a/activerecord/lib/active_record/autosave_association.rb b/activerecord/lib/active_record/autosave_association.rb
index 0b89a49896..cb5bc06580 100644
--- a/activerecord/lib/active_record/autosave_association.rb
+++ b/activerecord/lib/active_record/autosave_association.rb
@@ -217,7 +217,7 @@ module ActiveRecord
     # Returns whether or not this record has been changed in any way (including whether
     # any of its nested autosave associations are likewise changed)
     def changed_for_autosave?
-      new_record? || changed? || marked_for_destruction? || nested_records_changed_for_autosave?
+      !persisted? || changed? || marked_for_destruction? || nested_records_changed_for_autosave?
     end
 
     private
@@ -231,7 +231,7 @@ module ActiveRecord
       elsif autosave
         association.target.find_all { |record| record.changed_for_autosave? }
       else
-        association.target.find_all { |record| record.new_record? }
+        association.target.find_all { |record| !record.persisted? }
       end
     end
 
@@ -257,7 +257,7 @@ module ActiveRecord
     # +reflection+.
     def validate_collection_association(reflection)
       if association = association_instance_get(reflection.name)
-        if records = associated_records_to_validate_or_save(association, new_record?, reflection.options[:autosave])
+        if records = associated_records_to_validate_or_save(association, !persisted?, reflection.options[:autosave])
           records.each { |record| association_valid?(reflection, record) }
         end
       end
@@ -286,7 +286,7 @@ module ActiveRecord
     # Is used as a before_save callback to check while saving a collection
     # association whether or not the parent was a new record before saving.
     def before_save_collection_association
-      @new_record_before_save = new_record?
+      @new_record_before_save = !persisted?
       true
     end
 
@@ -308,7 +308,7 @@ module ActiveRecord
 
             if autosave && record.marked_for_destruction?
               association.destroy(record)
-            elsif autosave != false && (@new_record_before_save || record.new_record?)
+            elsif autosave != false && (@new_record_before_save || !record.persisted?)
               if autosave
                 saved = association.send(:insert_record, record, false, false)
               else
@@ -343,7 +343,7 @@ module ActiveRecord
           association.destroy
         else
           key = reflection.options[:primary_key] ? send(reflection.options[:primary_key]) : id
-          if autosave != false && (new_record? || association.new_record? || association[reflection.primary_key_name] != key || autosave)
+          if autosave != false && (!persisted? || !association.persisted? || association[reflection.primary_key_name] != key || autosave)
             association[reflection.primary_key_name] = key
             saved = association.save(:validate => !autosave)
             raise ActiveRecord::Rollback if !saved && autosave
@@ -363,7 +363,7 @@ module ActiveRecord
         if autosave && association.marked_for_destruction?
           association.destroy
         elsif autosave != false
-          saved = association.save(:validate => !autosave) if association.new_record? || autosave
+          saved = association.save(:validate => !autosave) if !association.persisted? || autosave
 
           if association.updated?
             association_id = association.send(reflection.options[:primary_key] || :id)
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 06a388cd21..b35f59d6df 100644
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -204,7 +204,7 @@ module ActiveRecord #:nodoc:
   #
   #   # No 'Winter' tag exists
   #   winter = Tag.find_or_initialize_by_name("Winter")
-  #   winter.new_record? # true
+  #   winter.persisted? # false
   #
   # To find by a subset of the attributes to be used for instantiating a new object, pass a hash instead of
   # a list of parameters.
@@ -1368,7 +1368,7 @@ MSG
       def initialize(attributes = nil)
         @attributes = attributes_from_column_definition
         @attributes_cache = {}
-        @new_record = true
+        @persisted = false
         @readonly = false
         @destroyed = false
         @marked_for_destruction = false
@@ -1403,7 +1403,7 @@ MSG
         clear_aggregation_cache
         clear_association_cache
         @attributes_cache = {}
-        @new_record = true
+        @persisted = false
         ensure_proper_type
 
         populate_with_current_scope_attributes
@@ -1422,7 +1422,8 @@ MSG
       def init_with(coder)
         @attributes = coder['attributes']
         @attributes_cache, @previously_changed, @changed_attributes = {}, {}, {}
-        @new_record = @readonly = @destroyed = @marked_for_destruction = false
+        @readonly = @destroyed = @marked_for_destruction = false
+        @persisted = true
         _run_find_callbacks
         _run_initialize_callbacks
       end
@@ -1463,7 +1464,7 @@ MSG
       #   Person.find(5).cache_key  # => "people/5-20071224150000" (updated_at available)
       def cache_key
         case
-        when new_record?
+        when !persisted?
           "#{self.class.model_name.cache_key}/new"
         when timestamp = self[:updated_at]
           "#{self.class.model_name.cache_key}/#{id}-#{timestamp.to_s(:number)}"
@@ -1581,11 +1582,20 @@ MSG
         self.class.columns_hash[name.to_s]
       end
 
-      # Returns true if the +comparison_object+ is the same object, or is of the same type and has the same id.
+      # Returns true if +comparison_object+ is the same exact object, or +comparison_object+ 
+      # is of the same type and +self+ has an ID and it is equal to +comparison_object.id+.
+      #
+      # Note that new records are different from any other record by definition, unless the
+      # other record is the receiver itself. Besides, if you fetch existing records with
+      # +select+ and leave the ID out, you're on your own, this predicate will return false.
+      #
+      # Note also that destroying a record preserves its ID in the model instance, so deleted
+      # models are still comparable.
       def ==(comparison_object)
         comparison_object.equal?(self) ||
-          (comparison_object.instance_of?(self.class) &&
-            comparison_object.id == id && !comparison_object.new_record?)
+          comparison_object.instance_of?(self.class) &&
+          id.present? &&
+          comparison_object.id == id
       end
 
       # Delegates to ==
@@ -1630,7 +1640,7 @@ MSG
       # Returns the contents of the record as a nicely formatted string.
       def inspect
         attributes_as_nice_string = self.class.column_names.collect { |name|
-          if has_attribute?(name) || new_record?
+          if has_attribute?(name) || !persisted?
             "#{name}: #{attribute_for_inspect(name)}"
           end
         }.compact.join(", ")
diff --git a/activerecord/lib/active_record/locking/optimistic.rb b/activerecord/lib/active_record/locking/optimistic.rb
index b6f87a57b8..bf626301f1 100644
--- a/activerecord/lib/active_record/locking/optimistic.rb
+++ b/activerecord/lib/active_record/locking/optimistic.rb
@@ -109,7 +109,7 @@ module ActiveRecord
         def destroy #:nodoc:
           return super unless locking_enabled?
 
-          unless new_record?
+          if persisted?
             lock_col = self.class.locking_column
             previous_value = send(lock_col).to_i
 
diff --git a/activerecord/lib/active_record/locking/pessimistic.rb b/activerecord/lib/active_record/locking/pessimistic.rb
index 9ad6a2baf7..d900831e13 100644
--- a/activerecord/lib/active_record/locking/pessimistic.rb
+++ b/activerecord/lib/active_record/locking/pessimistic.rb
@@ -47,7 +47,7 @@ module ActiveRecord
       # or pass true for "FOR UPDATE" (the default, an exclusive row lock).  Returns
       # the locked record.
       def lock!(lock = true)
-        reload(:lock => lock) unless new_record?
+        reload(:lock => lock) if persisted?
         self
       end
     end
diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb
index a4c09b654a..2c306d233a 100644
--- a/activerecord/lib/active_record/migration.rb
+++ b/activerecord/lib/active_record/migration.rb
@@ -387,6 +387,8 @@ module ActiveRecord
       def copy(destination, sources, options = {})
         copied = []
 
+        FileUtils.mkdir_p(destination) unless File.exists?(destination)
+
         destination_migrations = ActiveRecord::Migrator.migrations(destination)
         last = destination_migrations.last
         sources.each do |name, path|
diff --git a/activerecord/lib/active_record/nested_attributes.rb b/activerecord/lib/active_record/nested_attributes.rb
index aca91c907d..0c3392263a 100644
--- a/activerecord/lib/active_record/nested_attributes.rb
+++ b/activerecord/lib/active_record/nested_attributes.rb
@@ -323,7 +323,7 @@ module ActiveRecord
           (options[:update_only] || record.id.to_s == attributes['id'].to_s)
         assign_to_or_mark_for_destruction(record, attributes, options[:allow_destroy]) unless call_reject_if(association_name, attributes)
 
-      elsif attributes['id']
+      elsif attributes['id'].present?
         raise_nested_attributes_record_not_found(association_name, attributes['id'])
 
       elsif !reject_new_record?(association_name, attributes)
diff --git a/activerecord/lib/active_record/persistence.rb b/activerecord/lib/active_record/persistence.rb
index 707c1a05be..594a2214bb 100644
--- a/activerecord/lib/active_record/persistence.rb
+++ b/activerecord/lib/active_record/persistence.rb
@@ -4,7 +4,7 @@ module ActiveRecord
     # Returns true if this object hasn't been saved yet -- that is, a record
     # for the object doesn't exist in the data store yet; otherwise, returns false.
     def new_record?
-      @new_record
+      !@persisted
     end
 
     # Returns true if this object has been destroyed, otherwise returns false.
@@ -15,7 +15,7 @@ module ActiveRecord
     # Returns if the record is persisted, i.e. it's not a new record and it was
     # not destroyed.
     def persisted?
-      !(new_record? || destroyed?)
+      @persisted && !destroyed?
     end
 
     # Saves the model.
@@ -94,8 +94,9 @@ module ActiveRecord
       became = klass.new
       became.instance_variable_set("@attributes", @attributes)
       became.instance_variable_set("@attributes_cache", @attributes_cache)
-      became.instance_variable_set("@new_record", new_record?)
+      became.instance_variable_set("@persisted", persisted?)
       became.instance_variable_set("@destroyed", destroyed?)
+      became.type = klass.name unless self.class.descends_from_active_record?
       became
     end
 
@@ -240,7 +241,7 @@ module ActiveRecord
   private
     def create_or_update
       raise ReadOnlyRecord if readonly?
-      result = new_record? ? create : update
+      result = persisted? ? update : create
       result != false
     end
 
@@ -269,7 +270,7 @@ module ActiveRecord
 
       self.id ||= new_id
 
-      @new_record = false
+      @persisted = true
       id
     end
 
diff --git a/activerecord/lib/active_record/railtie.rb b/activerecord/lib/active_record/railtie.rb
index 868fd6c3ff..dfe255ad7c 100644
--- a/activerecord/lib/active_record/railtie.rb
+++ b/activerecord/lib/active_record/railtie.rb
@@ -14,7 +14,7 @@ module ActiveRecord
     config.active_record = ActiveSupport::OrderedOptions.new
 
     config.app_generators.orm :active_record, :migration => true,
-                                          :timestamps => true
+                                              :timestamps => true
 
     config.app_middleware.insert_after "::ActionDispatch::Callbacks",
       "ActiveRecord::QueryCache"
diff --git a/activerecord/lib/active_record/relation/calculations.rb b/activerecord/lib/active_record/relation/calculations.rb
index 6bf698fe97..c8adaddfca 100644
--- a/activerecord/lib/active_record/relation/calculations.rb
+++ b/activerecord/lib/active_record/relation/calculations.rb
@@ -208,14 +208,16 @@ module ActiveRecord
     end
 
     def execute_grouped_calculation(operation, column_name, distinct) #:nodoc:
-      group_attr      = @group_values.first
-      association     = @klass.reflect_on_association(group_attr.to_sym)
-      associated      = association && association.macro == :belongs_to # only count belongs_to associations
-      group_field     = associated ? association.primary_key_name : group_attr
-      group_alias     = column_alias_for(group_field)
-      group_column    = column_for(group_field)
+      group_attr      = @group_values
+      association     = @klass.reflect_on_association(group_attr.first.to_sym)
+      associated      = group_attr.size == 1 && association && association.macro == :belongs_to # only count belongs_to associations
+      group_fields  = Array(associated ? association.primary_key_name : group_attr)
+      group_aliases = group_fields.map { |field| column_alias_for(field) }
+      group_columns = group_aliases.zip(group_fields).map { |aliaz,field|
+        [aliaz, column_for(field)]
+      }
 
-      group = @klass.connection.adapter_name == 'FrontBase' ? group_alias : group_field
+      group = @klass.connection.adapter_name == 'FrontBase' ? group_aliases : group_fields
 
       if operation == 'count' && column_name == :all
         aggregate_alias = 'count_all'
@@ -223,22 +225,33 @@ module ActiveRecord
         aggregate_alias = column_alias_for(operation, column_name)
       end
 
-      relation = except(:group).group(group)
-      relation.select_values = [
-        operation_over_aggregate_column(aggregate_column(column_name), operation, distinct).as(aggregate_alias),
-        "#{group_field} AS #{group_alias}"
+      select_values = [
+        operation_over_aggregate_column(
+          aggregate_column(column_name),
+          operation,
+          distinct).as(aggregate_alias)
       ]
 
+      select_values.concat group_fields.zip(group_aliases).map { |field,aliaz|
+        "#{field} AS #{aliaz}"
+      }
+
+      relation = except(:group).group(group.join(','))
+      relation.select_values = select_values
+
       calculated_data = @klass.connection.select_all(relation.to_sql)
 
       if association
-        key_ids     = calculated_data.collect { |row| row[group_alias] }
+        key_ids     = calculated_data.collect { |row| row[group_aliases.first] }
         key_records = association.klass.base_class.find(key_ids)
         key_records = Hash[key_records.map { |r| [r.id, r] }]
       end
 
       ActiveSupport::OrderedHash[calculated_data.map do |row|
-        key = type_cast_calculated_value(row[group_alias], group_column)
+        key   = group_columns.map { |aliaz, column|
+          type_cast_calculated_value(row[aliaz], column)
+        }
+        key   = key.first if key.size == 1
         key = key_records[key] if associated
         [key, type_cast_calculated_value(row[aggregate_alias], column_for(column_name), operation)]
       end]
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index e9e9c85122..4192456447 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -300,7 +300,7 @@ module ActiveRecord
       unless record
         conditions = arel.where_sql
         conditions = " [#{conditions}]" if conditions
-        raise RecordNotFound, "Couldn't find #{@klass.name} with ID=#{id}#{conditions}"
+        raise RecordNotFound, "Couldn't find #{@klass.name} with #{@klass.primary_key}=#{id}#{conditions}"
       end
 
       record
diff --git a/activerecord/lib/active_record/relation/predicate_builder.rb b/activerecord/lib/active_record/relation/predicate_builder.rb
index c5428dccd6..32c7d08daa 100644
--- a/activerecord/lib/active_record/relation/predicate_builder.rb
+++ b/activerecord/lib/active_record/relation/predicate_builder.rb
@@ -25,6 +25,11 @@ module ActiveRecord
             attribute.in(values)
           when Range, Arel::Relation
             attribute.in(value)
+          when ActiveRecord::Base
+            attribute.eq(value.quoted_id)
+          when Class
+            # FIXME: I think we need to deprecate this behavior
+            attribute.eq(value.name)
           else
             attribute.eq(value)
           end
diff --git a/activerecord/lib/active_record/session_store.rb b/activerecord/lib/active_record/session_store.rb
index 3fc596e02a..ba99800fb2 100644
--- a/activerecord/lib/active_record/session_store.rb
+++ b/activerecord/lib/active_record/session_store.rb
@@ -228,7 +228,7 @@ module ActiveRecord
         @session_id     = attributes[:session_id]
         @data           = attributes[:data]
         @marshaled_data = attributes[:marshaled_data]
-        @new_record     = @marshaled_data.nil?
+        @persisted      = !@marshaled_data.nil?
       end
 
       # Lazy-unmarshal session state.
@@ -252,8 +252,8 @@ module ActiveRecord
         marshaled_data = self.class.marshal(data)
         connect        = connection
 
-        if @new_record
-          @new_record = false
+        unless @persisted
+          @persisted = true
           connect.update <<-end_sql, 'Create session'
             INSERT INTO #{table_name} (
               #{connect.quote_column_name(session_id_column)},
@@ -272,7 +272,7 @@ module ActiveRecord
       end
 
       def destroy
-        return if @new_record
+        return unless @persisted
 
         connect = connection
         connect.delete <<-end_sql, 'Destroy session'
@@ -321,6 +321,7 @@ module ActiveRecord
         if sid = current_session_id(env)
           Base.silence do
             get_session_model(env, sid).destroy
+            env[SESSION_RECORD_KEY] = nil
           end
         end
 
diff --git a/activerecord/lib/active_record/transactions.rb b/activerecord/lib/active_record/transactions.rb
index ab737f0f88..8c94d1a2bc 100644
--- a/activerecord/lib/active_record/transactions.rb
+++ b/activerecord/lib/active_record/transactions.rb
@@ -242,7 +242,7 @@ module ActiveRecord
       with_transaction_returning_status { super }
     end
 
-    # Reset id and @new_record if the transaction rolls back.
+    # Reset id and @persisted if the transaction rolls back.
     def rollback_active_record_state!
       remember_transaction_record_state
       yield
@@ -297,9 +297,9 @@ module ActiveRecord
     # Save the new record state and id of a record so it can be restored later if a transaction fails.
     def remember_transaction_record_state #:nodoc
       @_start_transaction_state ||= {}
-      unless @_start_transaction_state.include?(:new_record)
+      unless @_start_transaction_state.include?(:persisted)
         @_start_transaction_state[:id] = id if has_attribute?(self.class.primary_key)
-        @_start_transaction_state[:new_record] = @new_record
+        @_start_transaction_state[:persisted] = @persisted
       end
       unless @_start_transaction_state.include?(:destroyed)
         @_start_transaction_state[:destroyed] = @destroyed
@@ -323,7 +323,7 @@ module ActiveRecord
           restore_state = remove_instance_variable(:@_start_transaction_state)
           if restore_state
             @attributes = @attributes.dup if @attributes.frozen?
-            @new_record = restore_state[:new_record]
+            @persisted = restore_state[:persisted]
             @destroyed = restore_state[:destroyed]
             if restore_state[:id]
               self.id = restore_state[:id]
@@ -345,11 +345,11 @@ module ActiveRecord
     def transaction_include_action?(action) #:nodoc
       case action
       when :create
-        transaction_record_state(:new_record)
+        transaction_record_state(:new_record) || !transaction_record_state(:persisted)
       when :destroy
         destroyed?
       when :update
-        !(transaction_record_state(:new_record) || destroyed?)
+        !(transaction_record_state(:new_record) || !transaction_record_state(:persisted) || destroyed?)
       end
     end
   end
diff --git a/activerecord/lib/active_record/validations.rb b/activerecord/lib/active_record/validations.rb
index f367315b22..ee45fcdf35 100644
--- a/activerecord/lib/active_record/validations.rb
+++ b/activerecord/lib/active_record/validations.rb
@@ -51,7 +51,7 @@ module ActiveRecord
 
     # Runs all the specified validations and returns true if no errors were added otherwise false.
     def valid?(context = nil)
-      context ||= (new_record? ? :create : :update)
+      context ||= (persisted? ? :update : :create)
       output = super(context)
       errors.empty? && output
     end
diff --git a/activerecord/lib/active_record/validations/uniqueness.rb b/activerecord/lib/active_record/validations/uniqueness.rb
index a25558bd80..3eba7510ac 100644
--- a/activerecord/lib/active_record/validations/uniqueness.rb
+++ b/activerecord/lib/active_record/validations/uniqueness.rb
@@ -31,7 +31,7 @@ module ActiveRecord
           relation = relation.where(scope_item => scope_value)
         end
 
-        unless record.new_record?
+        if record.persisted?
           # TODO : This should be in Arel
           relation = relation.where("#{record.class.quoted_table_name}.#{record.class.primary_key} <> ?", record.send(:id))
         end
diff --git a/activerecord/lib/active_record/version.rb b/activerecord/lib/active_record/version.rb
index 89eba15be1..0667be7d23 100644
--- a/activerecord/lib/active_record/version.rb
+++ b/activerecord/lib/active_record/version.rb
@@ -3,8 +3,8 @@ module ActiveRecord
     MAJOR = 3
     MINOR = 1
     TINY  = 0
-    BUILD = "beta"
+    PRE   = "beta"
 
-    STRING = [MAJOR, MINOR, TINY, BUILD].join('.')
+    STRING = [MAJOR, MINOR, TINY, PRE].compact.join('.')
   end
 end