has_many through self_and_descendants

[zlw]

I've got 2 models: User and Contract. User has many contracts but he should be able to see all of his and his descendants contracts. I tried something like this:

class User < ActiveRecord::Base
  acts_as_tree
  has_many :contracts, through: :self_and_descendants
end

class Contract < ActiveRecord::Base
  belongs_to :user
end

but i'm getting:

1.9.3p194 :058 > User.find(3).contracts
  User Load (0.4ms)  SELECT "users".* FROM "users" WHERE "users"."id" = $1 LIMIT 1  [["id", 3]]
SystemStackError: stack level too deep
    from gems/activerecord-3.2.6/lib/active_record/reflection.rb:530

is it possible to do such thing?

[zlw]

well, it's definitely not my day ;)

class User < ActiveRecord::Base
  has_many :contracts, finder_sql: proc {
    Contract.where(user_id: self_and_descendant_ids).to_sql
  }
end

I'm sorry to have bothered you :)

[zlw]

well, it isn't great (even good) solution, cause it doesn't work with default has_many behavior. has_many will use default query when for example User#contracts.where(foo: :bar)

It should work just fine if self_and_descendants (and others) would be has_many :through relation, not habtm. It would be nested has_many :through which works fine in rails3. Is it possible to convert them?

[mceachen]

OK, I'll see how horrible it is (because I agree, your finder_sql is a nasty hack to have to do, and won't scale well).

[mceachen]

OK, try out 3.1.0 -- we're now using has_many :through.

[zlw]

nice :) I'll try out new version withnin few days and I'll write is it working fine

[zlw]

well, it does not work

has_many :contracts, through: :self_and_descendants

and i'm still getting

1.9.3p194 :008 > User.find(1).self_and_descendant_contracts
  User Load (0.4ms)  SELECT "users".* FROM "users" WHERE "users"."id" = $1 LIMIT 1  [["id", 1]]
SystemStackError: stack level too deep
    from ~/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/reflection.rb:530

[mceachen]

OK, I wrote an example in the specs and added support for your use case, but not using the has_many through, but by a different collection. This code is in 3.2.1.

class User < ActiveRecord::Base
  acts_as_tree 
  has_many :contracts
  def indirect_contracts
    Contract.where(:user_id => descendant_ids)
  end
end

class Contract < ActiveRecord::Base
  belongs_to :user
end

How's that?