Optimisation: when providing a scope as conditions, unnecessary DB hits are issued (cc2.0)

[gamov]

The two following lines issues unnecessary DB hits (calling empty? and present? on a AR:Relation):
https://github.com/ryanb/cancan/blob/2.0/lib/cancan/rule.rb#L42
changed to

@conditions.is_a?(ActiveRecord::Relation) || @conditions.empty? ? true : @base_behavior

maybe just testing if it's a hash and empty is enough…
then
https://github.com/ryanb/cancan/blob/2.0/lib/cancan/rule.rb#L59
changed to

@conditions.is_a?(ActiveRecord::Relation) || @conditions.present?

https://github.com/ryanb/cancan/blob/2.0/lib/cancan/rule.rb#L51
changed to

@block.nil? && conditions? && !@conditions.kind_of?(Hash) && !@conditions.is_a?(ActiveRecord::Relation)

lastly
https://github.com/ryanb/cancan/blob/2.0/lib/cancan/rule.rb#L63
to

@block || (!@conditions.is_a?(ActiveRecord::Relation) && conditions?)

I'm not making a pull request since I'm not sure of the implications of those changes.

PS: I'm posting this here since it's related to cc2.0

[xhoy]

Dear submitter, Since cancan/raynB hasn't been active for more than 6 months and no body else then ryam himself has commit permissions the cancan project is on a stand still.
Since cancan has several issues including missing support for rails 4 cancan is moving forward to cancancan. More details on: #994

If your feel that your pull request or bug is still applicable (and hasn't been merged in to cancan) it would be really appreciated if you would resubmit it to cancancan (https://github.com/cancancommunity/cancancan)

We hope to see you on the other side!