allow SQL conditions to be used with a block

lib/cancan/rule.rb

@@ -16,7 +16,7 @@ module CanCan
       @actions = [action].flatten
       @subjects = [subject].flatten
       @attributes = [extra_args.shift].flatten if extra_args.first.kind_of?(Symbol) || extra_args.first.kind_of?(Array) && extra_args.first.first.kind_of?(Symbol)
-      raise Error, "You are not able to supply a block with a hash of conditions in #{action} #{subject} ability. Use either one." if extra_args.first && !block.nil?
+      raise Error, "You are not able to supply a block with a hash of conditions in #{action} #{subject} ability. Use either one." if extra_args.first.kind_of?(Hash) && !block.nil?
       @conditions = extra_args.first || {}
       @block = block
     end

spec/cancan/ability_spec.rb

@@ -188,6 +188,14 @@ describe CanCan::Ability do
     }.should raise_error(CanCan::Error, "You are not able to supply a block with a hash of conditions in read ranges ability. Use either one.")
   end
 
+  it "does not raise an error when attempting to use a block with an array of SQL conditions" do
+    lambda {
+      @ability.can :read, :ranges, ["published = ?", true] do
+        false
+      end
+    }.should_not raise_error(CanCan::Error)
+  end
+
 
   # Attributes