How to override rails has_many cache

Question

I want to be able to manage has_many caching myself. The issue being I want to be able to archive (like soft delete, but with discardable gem) some records:

has_many :tags

def tag_list=(tag_names)

  # so I do a diff
  names_to_create = ...  
  tags_to_discard = ...
  tags_to_keep = ...

  to_delete.each(&:discard)
  new_tags = names_to_create.each { |name| tag.create!(name: name) }

  # if I just go with regular
  self.tags = new_tags + tags_to_keep
  # tags_to_discard will be deleted

The thing is that I don't want to just tags.reload. It's costly I know exactly what tags should be here or not.

How I can just "force" the rails cache?

Answer 1

You should tread carefully with that, but I find that

has_many :tags

def tag_list=(tag_names)

  # Do a diff
  names_to_create = ...  
  tags_to_discard = ...
  tags_to_keep = ...

  to_delete.each(&:discard)
  new_tags = names_to_create.each { |name| tag.create!(name: name) }

  tags.proxy_association.target = tags_to_keep + new tags
end

To do exactly that

Though it's probably private API and not meant to be used like that.