New multi-trees test, failing

[mkralla11]

I ran into the issue that has occurred for multiple programmers.
Issues:
#37 (Different issue: this is .hash_tree from a non-tree relation)
#76 (Different issue: this was fixed many versions ago, and has test coverage)
#28 (Different issue: this was fixed many versions ago, and has test coverage)

The issue is occurring because the call to hash_tree is on an already-scoped ActiveRecord relation, and your previous tests only cover Class.hash_tree.

example:

d = Tag.find_or_create_by_path %w[a b c d]
h = Tag.find_or_create_by_path %w[e f g h]

Tag.first.children.hash_tree

NoMethodError - undefined method `[]=' for nil:NilClass:
  (gem) closure_tree-5.1.1/lib/closure_tree/hash_tree.rb:52:in `block in build_hash_tree'
  (gem) activerecord-4.1.0/lib/active_record/relation/delegation.rb:46:in `each'
  (gem) closure_tree-5.1.1/lib/closure_tree/hash_tree.rb:47:in `build_hash_tree'
  (gem) closure_tree-5.1.1/lib/closure_tree/hash_tree.rb:23:in `hash_tree'
  (gem) activerecord-4.1.0/lib/active_record/relation/delegation.rb:94:in `block in method_missing'
  (gem) activerecord-4.1.0/lib/active_record/relation.rb:286:in `scoping'
  (gem) activerecord-4.1.0/lib/active_record/relation/delegation.rb:94:in `method_missing'
  app/controllers/aging_resources_controller.rb:34:in `load_resource'

I have updated all your tests to accommodate for the desired/intended behavior, and they all pass. I then wrote my own test that demonstrates the issue occurring and the test fails.

Let me know if you need any more info from me. The issue is occurring on line 52 of /lib/closure_tree/hash_tree.rb and it seems like there needs to be another conditional statement on line 49 to fix the problem, but I haven't had time to throw bricks at it yet. It might be an easy fix for you, @mceachen, so I thought I'd let you take a look.

Btw, I love this gem :). Nice work!

[mceachen]

Thanks for making those failing tests! I'll try to check them out when I've got a moment this next weekend.

[mceachen]

Ah, so I found the actual issue here—the node.children.hash_tree passes a scope that has a where condition (where the parent_id is the id of node)—which causes only the children to be returned from hash_tree.