1 files changed, 25 insertions, 36 deletions

diff --git a/activerecord/lib/active_record/associations/collection_association.rb b/activerecord/lib/active_record/associations/collection_association.rb
index 443ccaaa72..c3d4eab562 100644
--- a/activerecord/lib/active_record/associations/collection_association.rb
+++ b/activerecord/lib/active_record/associations/collection_association.rb
@@ -45,6 +45,8 @@ module ActiveRecord
       def ids_reader
         if loaded?
           target.pluck(reflection.association_primary_key)
+        elsif !target.empty?
+          load_target.pluck(reflection.association_primary_key)
         else
           @association_ids ||= scope.pluck(reflection.association_primary_key)
         end
@@ -103,15 +105,12 @@ module ActiveRecord
         if attributes.is_a?(Array)
           attributes.collect { |attr| build(attr, &block) }
         else
-          add_to_target(build_record(attributes)) do |record|
-            yield(record) if block_given?
-          end
+          add_to_target(build_record(attributes, &block))
         end
       end
 
-      # Add +records+ to this association. Returns +self+ so method calls may
-      # be chained. Since << flattens its argument list and inserts each record,
-      # +push+ and +concat+ behave identically.
+      # Add +records+ to this association. Since +<<+ flattens its argument list
+      # and inserts each record, +push+ and +concat+ behave identically.
       def concat(*records)
         records = records.flatten
         if owner.new_record?
@@ -212,9 +211,11 @@ module ActiveRecord
       def size
         if !find_target? || loaded?
           target.size
+        elsif @association_ids
+          @association_ids.size
         elsif !association_scope.group_values.empty?
           load_target.size
-        elsif !association_scope.distinct_value && target.is_a?(Array)
+        elsif !association_scope.distinct_value && !target.empty?
           unsaved_records = target.select(&:new_record?)
           unsaved_records.size + count_records
         else
@@ -231,10 +232,10 @@ module ActiveRecord
       # loaded and you are going to fetch the records anyway it is better to
       # check <tt>collection.length.zero?</tt>.
       def empty?
-        if loaded?
+        if loaded? || @association_ids || reflection.has_cached_counter?
           size.zero?
         else
-          @target.blank? && !scope.exists?
+          target.empty? && !scope.exists?
         end
       end
 
@@ -301,23 +302,6 @@ module ActiveRecord
       end
 
       private
-
-        def find_target
-          scope = self.scope
-          return scope.to_a if skip_statement_cache?(scope)
-
-          conn = klass.connection
-          sc = reflection.association_scope_cache(conn, owner) do |params|
-            as = AssociationScope.create { params.bind }
-            target_scope.merge!(as.scope(self))
-          end
-
-          binds = AssociationScope.get_bind_values(owner, reflection.chain)
-          sc.execute(binds, conn) do |record|
-            set_inverse_instance(record)
-          end
-        end
-
         # We have some records loaded from the database (persisted) and some that are
         # in-memory (memory). The same record may be represented in the persisted array
         # and in the memory array.
@@ -356,15 +340,17 @@ module ActiveRecord
           if attributes.is_a?(Array)
             attributes.collect { |attr| _create_record(attr, raise, &block) }
           else
+            record = build_record(attributes, &block)
             transaction do
-              add_to_target(build_record(attributes)) do |record|
-                yield(record) if block_given?
-                insert_record(record, true, raise) {
+              result = nil
+              add_to_target(record) do
+                result = insert_record(record, true, raise) {
                   @_was_loaded = loaded?
-                  @association_ids = nil
                 }
               end
+              raise ActiveRecord::Rollback unless result
             end
+            record
           end
         end
 
@@ -395,7 +381,8 @@ module ActiveRecord
           records.each { |record| callback(:before_remove, record) }
 
           delete_records(existing_records, method) if existing_records.any?
-          records.each { |record| target.delete(record) }
+          @target -= records
+          @association_ids = nil
 
           records.each { |record| callback(:after_remove, record) }
         end
@@ -408,9 +395,9 @@ module ActiveRecord
         end
 
         def replace_records(new_target, original_target)
-          delete(target - new_target)
+          delete(difference(target, new_target))
 
-          unless concat(new_target - target)
+          unless concat(difference(new_target, target))
             @target = original_target
             raise RecordNotSaved, "Failed to replace #{reflection.name} because one or more of the " \
                                   "new records could not be saved."
@@ -420,7 +407,7 @@ module ActiveRecord
         end
 
         def replace_common_records_in_memory(new_target, original_target)
-          common_records = new_target & original_target
+          common_records = intersection(new_target, original_target)
           common_records.each do |record|
             skip_callbacks = true
             replace_on_target(record, @target.index(record), skip_callbacks)
@@ -436,13 +423,14 @@ module ActiveRecord
               unless owner.new_record?
                 result &&= insert_record(record, true, raise) {
                   @_was_loaded = loaded?
-                  @association_ids = nil
                 }
               end
             end
           end
 
-          result && records
+          raise ActiveRecord::Rollback unless result
+
+          records
         end
 
         def replace_on_target(record, index, skip_callbacks)
@@ -457,6 +445,7 @@ module ActiveRecord
           if index
             target[index] = record
           elsif @_was_loaded || !loaded?
+            @association_ids = nil
             target << record
           end