raise an error when trying to make a rule with both hash conditions and a block - closes #269

lib/cancan/rule.rb

@@ -11,6 +11,7 @@ module CanCan
     # and subject respectively (such as :read, @project). The third argument is a hash
     # of conditions and the last one is the block passed to the "can" call.
     def initialize(base_behavior, action, subject, conditions, block)
+      raise Error, "You are not able to supply a block with a hash of conditions in #{action} #{subject} ability. Use either one." if conditions.kind_of?(Hash) && !block.nil?
       @match_all = action.nil? && subject.nil?
       @base_behavior = base_behavior
       @actions = [action].flatten

spec/cancan/ability_spec.rb

@@ -357,6 +357,14 @@ describe CanCan::Ability do
     @ability.model_adapter(model_class, :read).should == :adapter_instance
   end
 
+  it "should raise an error when attempting to use a block with a hash condition since it's not likely what they want" do
+    lambda {
+      @ability.can :read, Array, :published => true do
+        false
+      end
+    }.should raise_error(CanCan::Error, "You are not able to supply a block with a hash of conditions in read Array ability. Use either one.")
+  end
+
   describe "unauthorized message" do
     after(:each) do
       I18n.backend = nil