Ransack: has_many through association expecting param throws error

Question

Here's a generic approximation of my models, with a has_many through using a scope that expects a parameter

class GlobalCompany
  has_many :locations
  has_many :global_company_forms, :through => :locations
end

class Location
  belongs_to :global_company
  has_one :global_company_form
end

class Company
  belongs_to :global_company
  belongs_to :subdomain

  has_many :global_company_forms, ->(company) { for_company(company) }, :through => :global_company
end

class GlobalCompanyForm
  belongs_to :location
  belongs_to :subdomain_form

  scope :for_company, ->(company) {where(:subdomain_form_id => company.subdomain.subdomain_form.id)}
end

class SubdomainForm
  belongs_to :subdomain
end

Company.ransack(q).result will throw:

NoMethodError: undefined method `subdomain' for #<ActiveRecord::Associations::JoinDependency::JoinAssociation:0x007fbd227f0850>

when ransack accesses that association its passing in an association as the 'company', instead of a company record, hence the no method

I've looked around, but haven't found any similar examples and I cannot figure out how to make ransack respect this type of association/scope. The association itself works fine outside of ransack.

Answer 1

You just have to perform the join manually in your controller when specifying the table to draw results from:

@q= GlobalCompany.joins(:location, :global_company_forum).ransack(params[:q])

And when set up the form, use:

<%=f.search_field :global_company_forum_name_contains%>

And for results, just chain the models together:

global_company_instance.location.global_company_forum.name

I developed this based on a discussion here .