JoinDependency

This is a module with a singular purpose. It creates an ActiveRecord::Associations::JoinDependency from an ActiveRecord::Relation. That's it.

require 'join_dependency'

relation = Post.joins(:author)
JoinDependency.from_relation(relation)

And, in case you're trying to bend Active Record to your will, you can choose how certain joins get categorized:

JoinDependency.from_relation(relation) do |join|
  case join
  when Polyamorous::InnerJoin, Polyamorous::OuterJoin
    :stashed_association_join
  end
end

This library isn't meant for people. It's a library for libraries on top of other libraries that interact with libraries.