.each called twice

[jacquescrocker]

sort of a low priority bug, however I noticed that object @users will iterate over @users twice.

This is noticeable in ORMs that return criteria objects that execute the query on iteration (such as mongoid). So the query actually gets executed twice.

Probably something to watch for and maybe add a unit test for it at some point. Not a huge deal since I can do to_a on the object before rendering it to rabl.

[nesquena]

Thanks for the heads up, I will definitely check out how to fix this soon.

[nesquena]

I think this has been fixed, can you confirm if this still happens?

[nesquena]

Closing, re-open if you notice this in last version.

[jacquescrocker]

just switched my project's bundle to the git version. the kicker now gets executed 3 times :-)

[nesquena]

That is awesomely bad. Can you help me with a simple test sample? I have two AR models: Users and Address and User has_one address. I created a bunch of users in AR and then did:

get "/" do
  @users = User.includes(:address).where('name != ?', 'frank')
  render "users"
end

with users template:

object @users

attribute :id, :name, :age

child :address do
  attribute :street, :city
end

code :foo do |m|
  m.name + "!"
end

and the logs show this:

DEBUG - [14/Apr/2011 12:53:18] "User Load (0.8ms)  SELECT "users".* FROM "users" WHERE (name != 'frank')"
DEBUG - [14/Apr/2011 12:53:18] "Address Load (0.4ms)  SELECT "addresses".* FROM "addresses" WHERE ("addresses".user_id IN (1,2,3))"

I think I am doing the test wrong. Do you think this is criteria objects in mongoid specific? I do check respond_to? on the object once or twice, I wonder if even a respond_to? kicks the object.

[jacquescrocker]

no prob, here's a simple sample project that replicates the bug: http://cl.ly/231i0N0k2M1X0J0j3918

[nesquena]

Also, I pushed to git version a new little hack that should fix it when you use the collection declaration instead of object.

collection @users

instead of object will force the passed in object to a collection with to_a. I would prefer a more elegant solution though such that using the 'object' directly still works.

[nesquena]

Thanks will try to come up with a better solution based on that test project. Can you confirm if on latest git rev that using collection solves it at least?

[jacquescrocker]

cool, sounds good. i have a breakpoint in the rabl src code, tracing through it now. i'll let you know if i come up with anything

[nesquena]

Awesome thanks, would love to know the root cause of the three invocations.

[jacquescrocker]

hmm, it might just be a mongoid issue

e @_data.respond_to?(:each_pair)
MONGODB rabl['users'].find({})

[jacquescrocker]

ok, looks like this is just a mongoid issue. it's executing a query whenever respond_to? is called on the criteria object. the solution you added of doing a .to_a on the collection @users is great and should solve my issues in the meantime. thanks!

[nesquena]

Yeah kicking on respond_to? is kind of sloppy, tempted to report the issue for mongoid. AR and DM act as you'd expect (no kick). Cleaned up the implementation of collection, I don't think it's that bad of an approach to fixing this for now. I kind of think it is a bit cleaner to declare the collection explicitly anyways. Thanks for your help.