store aliases in a better structure

2 files changed, 20 insertions, 5 deletions

diff --git a/activerecord/lib/active_record/associations/join_dependency.rb b/activerecord/lib/active_record/associations/join_dependency.rb
index 4635601781..94255fc74f 100644
--- a/activerecord/lib/active_record/associations/join_dependency.rb
+++ b/activerecord/lib/active_record/associations/join_dependency.rb
@@ -82,13 +82,26 @@ module ActiveRecord
         make_joins join_root
       end
 
-      def columns
-        join_root.collect { |join_part|
+      class Aliases
+        def initialize(tables)
+          @tables = tables
+        end
+
+        def columns
+          @tables.flat_map { |t| t.columns }
+        end
+
+        Table = Struct.new(:table, :columns)
+      end
+
+      def aliases
+        Aliases.new join_root.map { |join_part|
           table = join_part.aliased_table
-          join_part.column_names_with_alias.collect{ |column_name, aliased_name|
+          columns = join_part.column_names_with_alias.collect{ |column_name, aliased_name|
             table[column_name].as Arel.sql(aliased_name)
           }
-        }.flatten
+          Aliases::Table.new(table, columns)
+        }
       end
 
       def instantiate(result_set)
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index 92969cfb30..5e11ba0325 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -243,7 +243,9 @@ module ActiveRecord
     def find_with_associations
       join_dependency = construct_join_dependency
       relation = except :select
-      relation = relation.select(join_dependency.columns)
+
+      aliases  = join_dependency.aliases
+      relation = relation.select aliases.columns
       relation = apply_join_dependency(relation, join_dependency)
 
       if block_given?