class Bundler::Molinillo::Resolver::Resolution

def unwind_options_for_requirements(binding_requirements)
  unwind_details = []
  trees = []
  binding_requirements.reverse_each do |r|
    partial_tree = [r]
    trees << partial_tree
    unwind_details << UnwindDetails.new(-1, nil, partial_tree, binding_requirements, trees, [])
    # If this requirement has alternative possibilities, check if any would
    # satisfy the other requirements that created this conflict
    requirement_state = find_state_for(r)
    if conflict_fixing_possibilities?(requirement_state, binding_requirements)
      unwind_details << UnwindDetails.new(
        states.index(requirement_state),
        r,
        partial_tree,
        binding_requirements,
        trees,
        []
      )
    end
    # Next, look at the parent of this requirement, and check if the requirement
    # could have been avoided if an alternative PossibilitySet had been chosen
    parent_r = parent_of(r)
    next if parent_r.nil?
    partial_tree.unshift(parent_r)
    requirement_state = find_state_for(parent_r)
    if requirement_state.possibilities.any? { |set| !set.dependencies.include?(r) }
      unwind_details << UnwindDetails.new(
        states.index(requirement_state),
        parent_r,
        partial_tree,
        binding_requirements,
        trees,
        []
      )
    end
    # Finally, look at the grandparent and up of this requirement, looking
    # for any possibilities that wouldn't create their parent requirement
    grandparent_r = parent_of(parent_r)
    until grandparent_r.nil?
      partial_tree.unshift(grandparent_r)
      requirement_state = find_state_for(grandparent_r)
      if requirement_state.possibilities.any? { |set| !set.dependencies.include?(parent_r) }
        unwind_details << UnwindDetails.new(
          states.index(requirement_state),
          grandparent_r,
          partial_tree,
          binding_requirements,
          trees,
          []
        )
      end
      parent_r = grandparent_r
      grandparent_r = parent_of(parent_r)
    end
  end
  unwind_details
end