automatically add references when we can

activerecord/lib/active_record/relation/predicate_builder.rb

@@ -21,6 +21,18 @@ module ActiveRecord
       predicates.flatten
     end
 
+    def self.references(attributes)
+      references = attributes.map do |key, value|
+        if value.is_a?(Hash)
+          key
+        else
+          key = key.to_s
+          key.split('.').first.to_sym if key.include?('.')
+        end
+      end
+      references.compact
+    end
+
     private
       def self.build(attribute, value)
         case value

activerecord/lib/active_record/relation/query_methods.rb

@@ -52,7 +52,7 @@ module ActiveRecord
       return self if args.blank?
 
       relation = clone
-      relation.references_values = (references_values + args).uniq
+      relation.references_values = (references_values + args).flatten.uniq
       relation
     end
 
@@ -151,6 +151,7 @@ module ActiveRecord
       return self if opts.blank?
 
       relation = clone
+      relation = relation.references(PredicateBuilder.references(opts)) if Hash === opts
       relation.where_values += build_where(opts, rest)
       relation
     end
@@ -159,6 +160,7 @@ module ActiveRecord
       return self if opts.blank?
 
       relation = clone
+      relation = relation.references(PredicateBuilder.references(opts)) if Hash === opts
       relation.having_values += build_where(opts, rest)
       relation
     end

activerecord/test/cases/relations_test.rb

@@ -1175,4 +1175,18 @@ class RelationTest < ActiveRecord::TestCase
     scope = Post.references(:comments)
     assert !scope.eager_loading?
   end
+
+  def test_automatically_added_references
+    scope = Post.where(:comments => { :body => "Bla" })
+    assert_equal [:comments], scope.references_values
+
+    scope = Post.where('comments.body' => 'Bla')
+    assert_equal [:comments], scope.references_values
+
+    scope = Post.having(:comments => { :body => "Bla" })
+    assert_equal [:comments], scope.references_values
+
+    scope = Post.having('comments.body' => 'Bla')
+    assert_equal [:comments], scope.references_values
+  end
 end