Fix to handle MetaWhere and non-MetaWhere conditions correctly.

lib/cancan/model_adapters/active_record_adapter.rb

@@ -89,7 +89,12 @@ module CanCan
         if override_scope
           @model_class.scoped.merge(override_scope)
         elsif @model_class.respond_to?(:where) && @model_class.respond_to?(:joins)
+          mergeable_conditions = @rules.select {|rule| rule.unmergeable? }.blank?
+          if mergeable_conditions
             @model_class.where(conditions).joins(joins)
+          else
+            @model_class.where(*(@rules.map(&:conditions))).joins(joins)
+          end
         else
           @model_class.scoped(:conditions => conditions, :joins => joins)
         end

lib/cancan/rule.rb

@@ -54,6 +54,10 @@ module CanCan
       @conditions == {} || @conditions.nil?
     end
 
+    def unmergeable?
+      @conditions.respond_to?(:keys) && (! @conditions.keys.first.kind_of? Symbol)
+    end
+
     def associations_hash(conditions = @conditions)
       hash = {}
       conditions.map do |name, value|

spec/cancan/model_adapters/active_record_adapter_spec.rb

@@ -236,6 +236,16 @@ if ENV["MODEL_ADAPTER"].nil? || ENV["MODEL_ADAPTER"] == "active_record"
       @ability.should_not be_able_to(:read, article2)
     end
 
+    it "should merge MetaWhere and non-MetaWhere conditions" do
+      @ability.can :read, Article, :priority.lt => 2
+      @ability.can :read, Article, :priority => 1
+      article1 = Article.create!(:priority => 1)
+      article2 = Article.create!(:priority => 3)
+      Article.accessible_by(@ability).should == [article1]
+      @ability.should be_able_to(:read, article1)
+      @ability.should_not be_able_to(:read, article2)
+    end
+
     it "should match any MetaWhere condition" do
       adapter = CanCan::ModelAdapters::ActiveRecordAdapter
       article1 = Article.new(:priority => 1, :name => "Hello World")

spec/cancan/rule_spec.rb

@@ -36,4 +36,11 @@ describe CanCan::Rule do
     rule = CanCan::Rule.new(true, :read, Integer, nil, nil)
     rule.associations_hash.should == {}
   end
+
+  it "should not be mergeable if conditions are not simple hashes" do
+    meta_where = OpenStruct.new(:name => 'metawhere', :column => 'test')
+    @conditions[meta_where] = :bar
+
+    @rule.should be_unmergeable
+  end
 end