Create an Arel::Header class representing a relation's attributes

2 files changed, 9 insertions, 5 deletions

diff --git a/lib/arel/engines/sql/relations/operations/join.rb b/lib/arel/engines/sql/relations/operations/join.rb
index 7fad6400ad..9733657365 100644
--- a/lib/arel/engines/sql/relations/operations/join.rb
+++ b/lib/arel/engines/sql/relations/operations/join.rb
@@ -10,7 +10,7 @@ module Arel
           join_sql,
           relation2.externalize.table_sql(formatter),
           ("ON" unless predicates.blank?),
-          (ons + relation2.externalize.wheres).collect { |p| p.bind(environment).to_sql(Sql::WhereClause.new(environment)) }.join(' AND ')
+          (ons + relation2.externalize.wheres).collect { |p| p.bind(environment.relation).to_sql(Sql::WhereClause.new(environment)) }.join(' AND ')
         ].compact.join(" ")
         [relation1.joins(environment), this_join, relation2.joins(environment)].compact.join(" ")
       end
diff --git a/lib/arel/engines/sql/relations/table.rb b/lib/arel/engines/sql/relations/table.rb
index 8ee7a94357..7940fd781f 100644
--- a/lib/arel/engines/sql/relations/table.rb
+++ b/lib/arel/engines/sql/relations/table.rb
@@ -42,11 +42,14 @@ module Arel
     def attributes
       return @attributes if defined?(@attributes)
       if table_exists?
-        @attributes = columns.collect do |column|
-          Sql::Attributes.for(column).new(column, self, column.name.to_sym)
+        @attributes ||= begin
+          attrs = columns.collect do |column|
+            Sql::Attributes.for(column).new(column, self, column.name.to_sym)
+          end
+          Header.new(attrs)
         end
       else
-        []
+        Header.new
       end
     end
 
@@ -67,7 +70,8 @@ module Arel
     end
 
     def reset
-      @attributes = @columns = nil
+      @columns = nil
+      @attributes = Header.new([])
     end
 
     def ==(other)