From a6ba601d7dbd185ac5c5e60b588e5b4d9100ca02 Mon Sep 17 00:00:00 2001
From: Ivan Hamilton <ivan@chimerical.com.au>
Date: Thu, 20 Feb 2014 23:17:50 +1100
Subject: [PATCH] -Fixed reference loop checking (check reference, not
 equality)

---
 .../ReferenceLoopHandlingTests.cs             | 33 +++++++++++++++++++
 .../JsonSerializerInternalWriter.cs           |  2 +-
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/Src/Newtonsoft.Json.Tests/Serialization/ReferenceLoopHandlingTests.cs b/Src/Newtonsoft.Json.Tests/Serialization/ReferenceLoopHandlingTests.cs
index 324ae4002..0dc88c559 100644
--- a/Src/Newtonsoft.Json.Tests/Serialization/ReferenceLoopHandlingTests.cs
+++ b/Src/Newtonsoft.Json.Tests/Serialization/ReferenceLoopHandlingTests.cs
@@ -55,6 +55,23 @@ public void ReferenceLoopHandlingTest()
             Assert.AreEqual(ReferenceLoopHandling.Ignore, attribute.ReferenceLoopHandling);
         }
 
+        [Test]
+        public void HandleObjectReferenceLoopBadEquality()
+        {
+            ReferenceLoopHandlingObjectBadEquality o = new ReferenceLoopHandlingObjectBadEquality();
+            o.Value = new ReferenceLoopHandlingObjectBadEquality();
+
+            string json = JsonConvert.SerializeObject(o, Formatting.Indented, new JsonSerializerSettings
+            {
+                ReferenceLoopHandling = ReferenceLoopHandling.Error
+            });
+            Assert.AreEqual(@"{
+  ""Value"": {
+    ""Value"": null
+  }
+}", json);
+        }
+
         [Test]
         public void IgnoreObjectReferenceLoop()
         {
@@ -306,6 +323,22 @@ public class ReferenceLoopHandlingDictionary : Dictionary<string, ReferenceLoopH
     {
     }
 
+    [JsonObject(ItemReferenceLoopHandling = ReferenceLoopHandling.Error)]
+    public class ReferenceLoopHandlingObjectBadEquality
+    {
+        public override bool Equals(object obj)
+        {
+            return true;
+        }
+
+        public override int GetHashCode()
+        {
+            return 0;
+        }
+
+        public ReferenceLoopHandlingObjectBadEquality Value { get; set; }
+    }
+
     [JsonObject(ItemReferenceLoopHandling = ReferenceLoopHandling.Ignore)]
     public class ReferenceLoopHandlingObjectContainerAttribute
     {
diff --git a/Src/Newtonsoft.Json/Serialization/JsonSerializerInternalWriter.cs b/Src/Newtonsoft.Json/Serialization/JsonSerializerInternalWriter.cs
index 81f4aaa3f..c3c94e5dd 100644
--- a/Src/Newtonsoft.Json/Serialization/JsonSerializerInternalWriter.cs
+++ b/Src/Newtonsoft.Json/Serialization/JsonSerializerInternalWriter.cs
@@ -264,7 +264,7 @@ private bool CheckForCircularReference(JsonWriter writer, object value, JsonProp
             if (referenceLoopHandling == null && containerContract != null)
                 referenceLoopHandling = containerContract.ItemReferenceLoopHandling;
 
-            if (_serializeStack.IndexOf(value) != -1)
+            if (_serializeStack.IndexOf(o => ReferenceEquals(o,value)) != -1)
             {
                 string message = "Self referencing loop detected";
                 if (property != null)