Ensure that association_ids uses the correct attribute where the association is a has_many :through with a :primary_key option on the source reflection. [#6376 state:resolved]

2 files changed, 9 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index a2db592c7d..529d8ca2d3 100644
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -1582,9 +1582,12 @@ module ActiveRecord
 
           redefine_method("#{reflection.name.to_s.singularize}_ids") do
             if send(reflection.name).loaded? || reflection.options[:finder_sql]
-              send(reflection.name).map { |r| r.id }
+              records = send(reflection.name)
+              records.map { |r| r.send(reflection.association_primary_key) }
             else
-              send(reflection.name).select("#{reflection.quoted_table_name}.#{reflection.klass.primary_key}").except(:includes).map! { |r| r.id }
+              column  = "#{reflection.quoted_table_name}.#{reflection.association_primary_key}"
+              records = send(reflection.name).select(column).except(:includes)
+              records.map! { |r| r.send(reflection.association_primary_key) }
             end
           end
         end
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index ceeb0ec39d..0a0e8d650c 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -394,6 +394,10 @@ module ActiveRecord
         @source_reflection_names ||= (options[:source] ? [options[:source]] : [name.to_s.singularize, name]).collect { |n| n.to_sym }
       end
 
+      def association_primary_key
+        source_reflection.association_primary_key
+      end
+
       def check_validity!
         if through_reflection.nil?
           raise HasManyThroughAssociationNotFoundError.new(active_record.name, self)