1 files changed, 69 insertions, 28 deletions

diff --git a/activerecord/lib/active_record/associations/preloader/association.rb b/activerecord/lib/active_record/associations/preloader/association.rb
index cbf5e734ea..7d6523dbc4 100644
--- a/activerecord/lib/active_record/associations/preloader/association.rb
+++ b/activerecord/lib/active_record/associations/preloader/association.rb
@@ -3,6 +3,7 @@ module ActiveRecord
     class Preloader
       class Association #:nodoc:
         attr_reader :owners, :reflection, :preload_scope, :model, :klass
+        attr_reader :preloaded_records
 
         def initialize(klass, owners, reflection, preload_scope)
           @klass         = klass
@@ -12,15 +13,14 @@ module ActiveRecord
           @model         = owners.first && owners.first.class
           @scope         = nil
           @owners_by_key = nil
+          @preloaded_records = []
         end
 
-        def run
-          unless owners.first.association(reflection.name).loaded?
-            preload
-          end
+        def run(preloader)
+          preload(preloader)
         end
 
-        def preload
+        def preload(preloader)
           raise NotImplementedError
         end
 
@@ -29,6 +29,10 @@ module ActiveRecord
         end
 
         def records_for(ids)
+          query_scope(ids)
+        end
+
+        def query_scope(ids)
           scope.where(association_key.in(ids))
         end
 
@@ -52,13 +56,16 @@ module ActiveRecord
           raise NotImplementedError
         end
 
-        # We're converting to a string here because postgres will return the aliased association
-        # key in a habtm as a string (for whatever reason)
         def owners_by_key
-          @owners_by_key ||= owners.group_by do |owner|
-            key = owner[owner_key_name]
-            key && key.to_s
-          end
+          @owners_by_key ||= if key_conversion_required?
+                               owners.group_by do |owner|
+                                 owner[owner_key_name].to_s
+                               end
+                             else
+                               owners.group_by do |owner|
+                                 owner[owner_key_name]
+                               end
+                             end
         end
 
         def options
@@ -67,53 +74,87 @@ module ActiveRecord
 
         private
 
-        def associated_records_by_owner
+        def associated_records_by_owner(preloader)
           owners_map = owners_by_key
           owner_keys = owners_map.keys.compact
 
-          if klass.nil? || owner_keys.empty?
-            records = []
-          else
-            # Some databases impose a limit on the number of ids in a list (in Oracle it's 1000)
-            # Make several smaller queries if necessary or make one query if the adapter supports it
-            sliced  = owner_keys.each_slice(model.connection.in_clause_length || owner_keys.size)
-            records = sliced.map { |slice| records_for(slice).to_a }.flatten
+          # Each record may have multiple owners, and vice-versa
+          records_by_owner = owners.each_with_object({}) do |owner,h|
+            h[owner] = []
           end
 
-          # Each record may have multiple owners, and vice-versa
-          records_by_owner = Hash[owners.map { |owner| [owner, []] }]
-          records.each do |record|
-            owner_key = record[association_key_name].to_s
+          if owner_keys.any?
+            # Some databases impose a limit on the number of ids in a list (in Oracle it's 1000)
+            # Make several smaller queries if necessary or make one query if the adapter supports it
+            sliced  = owner_keys.each_slice(klass.connection.in_clause_length || owner_keys.size)
 
-            owners_map[owner_key].each do |owner|
-              records_by_owner[owner] << record
+            records = load_slices sliced
+            records.each do |record, owner_key|
+              owners_map[owner_key].each do |owner|
+                records_by_owner[owner] << record
+              end
             end
           end
+
           records_by_owner
         end
 
+        def key_conversion_required?
+          association_key_type != owner_key_type
+        end
+
+        def association_key_type
+          @klass.type_for_attribute(association_key_name.to_s).type
+        end
+
+        def owner_key_type
+          @model.type_for_attribute(owner_key_name.to_s).type
+        end
+
+        def load_slices(slices)
+          @preloaded_records = slices.flat_map { |slice|
+            records_for(slice)
+          }
+
+          @preloaded_records.map { |record|
+            key = record[association_key_name]
+            key = key.to_s if key_conversion_required?
+
+            [record, key]
+          }
+        end
+
         def reflection_scope
           @reflection_scope ||= reflection.scope ? klass.unscoped.instance_exec(nil, &reflection.scope) : klass.unscoped
         end
 
         def build_scope
           scope = klass.unscoped
-          scope.default_scoped = true
 
           values         = reflection_scope.values
+          reflection_binds = reflection_scope.bind_values
           preload_values = preload_scope.values
+          preload_binds  = preload_scope.bind_values
 
           scope.where_values      = Array(values[:where])      + Array(preload_values[:where])
           scope.references_values = Array(values[:references]) + Array(preload_values[:references])
+          scope.bind_values       = (reflection_binds + preload_binds)
 
-          scope.select!   preload_values[:select] || values[:select] || table[Arel.star]
+          scope._select!   preload_values[:select] || values[:select] || table[Arel.star]
           scope.includes! preload_values[:includes] || values[:includes]
+          scope.joins! preload_values[:joins] || values[:joins]
+          scope.order! preload_values[:order] || values[:order]
+
+          if preload_values[:readonly] || values[:readonly]
+            scope.readonly!
+          end
 
           if options[:as]
             scope.where!(klass.table_name => { reflection.type => model.base_class.sti_name })
           end
 
-          scope
+          scope.unscope_values = Array(values[:unscope])
+          klass.default_scoped.merge(scope)
         end
       end
     end