Fix marshal extension

lib/rspec/mocks/extensions/marshal.rb

@@ -7,6 +7,8 @@ def dump_with_mocks(*args)
       return dump_without_mocks(*args.unshift(object)) unless object.instance_variable_defined?(:@mock_proxy)
 
       mp = object.instance_variable_get(:@mock_proxy)
+      return dump_without_mocks(*args.unshift(object)) unless mp.is_a?(::RSpec::Mocks::Proxy)
+
       object.send(:remove_instance_variable, :@mock_proxy)
 
       begin

spec/rspec/mocks/serialization_spec.rb

@@ -5,6 +5,18 @@ module RSpec
   module Mocks
     class SerializableStruct < Struct.new(:foo, :bar); end
 
+    class SerializableMockProxy
+      attr_reader :mock_proxy
+
+      def initialize(mock_proxy)
+        @mock_proxy = mock_proxy
+      end
+
+      def ==(other)
+        other.class == self.class && other.mock_proxy == mock_proxy
+      end
+    end
+
     describe Serialization do
       def self.with_yaml_loaded(&block)
         context 'with YAML loaded' do
@@ -62,6 +74,15 @@ def set_stub
       it 'marshals the same with and without stubbing' do
         expect { set_stub }.to_not change { Marshal.dump(subject) }
       end
+
+      describe "an object that has its own mock_proxy instance variable" do
+        subject { SerializableMockProxy.new(:my_mock_proxy) }
+
+        it 'does not interfere with its marshalling' do
+          marshalled_copy = Marshal.load(Marshal.dump(subject))
+          marshalled_copy.should == subject
+        end
+      end
     end
   end
 end