1 files changed, 4 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
index fd23e59e82..b5d8de2544 100644
--- a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
@@ -29,6 +29,10 @@ module ActiveRecord
         end
 
         def insert_record(record, force = true, validate = true)
+          if ActiveRecord::Base.connection.supports_primary_key? && ActiveRecord::Base.connection.primary_key(@reflection.options[:join_table])
+            raise ActiveRecord::ConfigurationError, "Primary key is not allowed in a has_and_belongs_to_many join table (#{@reflection.options[:join_table]})."
+          end
+
           if record.new_record?
             if force
               record.save!