remove HABTM special cases from associations classes

activerecord/lib/active_record/associations/association_scope.rb

@@ -44,18 +44,6 @@ def add_constraints(scope)
         chain.each_with_index do |reflection, i|
           table, foreign_table = tables.shift, tables.first
 
-          if reflection.source_macro == :has_and_belongs_to_many
-            join_table = tables.shift
-
-            scope = scope.joins(join(
-              join_table,
-              table[reflection.association_primary_key].
-                eq(join_table[reflection.association_foreign_key])
-            ))
-
-            table, foreign_table = join_table, tables.first
-          end
-
           if reflection.source_macro == :belongs_to
             if reflection.options[:polymorphic]
               key = reflection.association_primary_key(self.klass)

activerecord/lib/active_record/associations/join_dependency.rb

@@ -216,7 +216,7 @@ def construct_association(record, join_part, row)
         else
           association = join_part.instantiate(row) unless row[join_part.aliased_primary_key].nil?
           case macro
-          when :has_many, :has_and_belongs_to_many
+          when :has_many
             other = record.association(join_part.reflection.name)
             other.loaded!
             other.target.push(association) if association

activerecord/lib/active_record/associations/join_dependency/join_association.rb

@@ -83,17 +83,6 @@ def join_constraints
             when :belongs_to
               key         = reflection.association_primary_key
               foreign_key = reflection.foreign_key
-            when :has_and_belongs_to_many
-              # Join the join table first...
-              joins << join(
-                table,
-                table[reflection.foreign_key].
-                  eq(foreign_table[reflection.active_record_primary_key]))
-
-              foreign_table, table = table, tables.shift
-
-              key         = reflection.association_primary_key
-              foreign_key = reflection.association_foreign_key
             else
               key         = reflection.foreign_key
               foreign_key = reflection.active_record_primary_key

activerecord/lib/active_record/associations/join_helper.rb

@@ -16,13 +16,6 @@ def construct_tables
             table_name_for(reflection),
             table_alias_for(reflection, reflection != self.reflection)
           )
-
-          if reflection.source_macro == :has_and_belongs_to_many
-            tables << alias_tracker.aliased_table_for(
-              reflection.source_reflection.join_table,
-              table_alias_for(reflection, true)
-            )
-          end
         end
         tables
       end