Multiple polymorphic associations on the same object

Question

I have a Flag model which is joined to multiple other objects with FlagInstance and a polymorphic flaggable on that table:

table 'flag_instances'
flag_id
flaggable_id
flaggable_type
.....

With has many_through I'm able to fetch any flaggable object like user.flags which is great.

However I'm trying to flag objects with errors and the notify other objects so I've added

table 'flag_instances'
flag_id
flaggable_id
flaggable_type
notifiable_id
notifiable_type
.....

The problem is, a User can have a flag and can be notified of a flag. So user.flags isn't specific enough to show me which is a flag and which is a notification of a flag.

I think I need to change the relationships:

user.rb
has_many :flag_instances, as: :flaggable, dependent: :destroy
has_many :flags, through: :flag_instances
has_many :flag_instances, as: :notifiable, dependent: :destroy
has_many :flags, through: :flag_instances

But I'm not sure what to change them to. Can someone please suggest a solution?

Note: both flags and notifications of flags can belong to multiple objects, so they both need to remain polymorphic.

Thanks

Answer 1

Association for notifiable needs to be changed. In this case user.rb:

has_many :flag_instances, as: :flaggable, dependent: :destroy
has_many :flags, through: :flag_instances

has_many :notifiables, as: :notifiable, dependent: :destroy, class_name: 'FlagInstance'
has_many :notifications, through: :notifiables, class_name: 'Flag'

Note: You might also need to provide foreign_key in case Rails association is not able to pick up the key itself.