Fix bug with Mongoid document where :manage :all caused accessible_by to return nothing and add specs to test for :manage :all.

lib/cancan/mongoid_additions.rb

@@ -22,10 +22,19 @@ module CanCan
     end    
     
     def conditions
+      if @can_definitions.size == 0
+        false_query
+      else
         @can_definitions.first.instance_variable_get(:@conditions)
       end
     end
     
+    def false_query
+      # this query is sure to return no results
+      {:_id => {'$exists' => false, '$type' => 7}}  # type 7 is an ObjectID (default for _id)      
+    end
+  end
+
   # customize to handle Mongoid queries in ability definitions conditions
   class CanDefinition
     def matches_conditions_hash?(subject, conditions = @conditions)          
@@ -83,16 +92,9 @@ module CanCan
       # internally uses Ability#conditions method, see that for more information.
       def accessible_by(ability, action = :read)        
         query = ability.query(action, self)     
-           
-        if query.conditions.blank?
-          # this query is sure to return no results
-          # we need this so there is a Mongoid::Criteria object to return, since an empty array would cause problems
-          where({:_id => {'$exists' => false, '$type' => 7}})  # type 7 is an ObjectID (default for _id)
-        else   
         where(query.conditions)
       end
     end
-    end
     
     def self.included(base)
       base.extend ClassMethods

spec/cancan/mongoid_additions_spec.rb

@@ -55,7 +55,7 @@ describe CanCan::MongoidAdditions do
     @model_class.create :title  => 'Lord'
     @model_class.create :title  => 'Dude'
       
-    @model_class.accessible_by(@ability, :read).should == []
+    @model_class.accessible_by(@ability, :read).entries.should == []
   end
   
   it "should return the correct records based on the defined ability" do
@@ -67,6 +67,16 @@ describe CanCan::MongoidAdditions do
     @model_class.accessible_by(@ability, :read).should == [sir]
   end  
 
+  it "should return everything when the defined ability is manage all" do
+    @ability.can :manage, :all
+    sir   = @model_class.create :title  => 'Sir'
+    lord  = @model_class.create :title  => 'Lord'
+    dude  = @model_class.create :title  => 'Dude'  
+    
+    @model_class.accessible_by(@ability, :read).entries.should == [sir, lord, dude]
+  end  
+
+  
   describe "Mongoid::Criteria where clause Symbol extensions using MongoDB expressions" do
     it "should handle :field.in" do
       obj = @model_class.create :title  => 'Sir'