From 4d425ccd06a834414db0efd13a1beb149258bfe4 Mon Sep 17 00:00:00 2001
From: James Newton-King <james@newtonking.com>
Date: Thu, 8 Dec 2016 09:47:01 +1300
Subject: [PATCH] -Fix merging null with complex type and
 MergeNullValueHandling.Ignore

---
 Src/Newtonsoft.Json.Tests/Linq/MergeTests.cs | 65 ++++++++++++++++++++
 Src/Newtonsoft.Json/Linq/JObject.cs          |  6 +-
 2 files changed, 66 insertions(+), 5 deletions(-)

diff --git a/Src/Newtonsoft.Json.Tests/Linq/MergeTests.cs b/Src/Newtonsoft.Json.Tests/Linq/MergeTests.cs
index 9005d69f..378df80b 100644
--- a/Src/Newtonsoft.Json.Tests/Linq/MergeTests.cs
+++ b/Src/Newtonsoft.Json.Tests/Linq/MergeTests.cs
@@ -596,5 +596,70 @@ namespace Newtonsoft.Json.Tests.Linq
             Assert.IsNotNull(source["Property5"]);
             Assert.AreEqual(JTokenType.Null, source["Property5"].Type);
         }
+
+        [Test]
+        public void MergeNullValueHandling_Array()
+        {
+            string originalJson = @"{
+  ""Bar"": [
+    ""a"",
+    ""b"",
+    ""c""
+  ]
+}";
+            string newJson = @"{
+  ""Bar"": null
+}";
+
+            JObject oldFoo = JObject.Parse(originalJson);
+            JObject newFoo = JObject.Parse(newJson);
+
+            oldFoo.Merge(newFoo, new JsonMergeSettings
+            {
+                MergeNullValueHandling = MergeNullValueHandling.Ignore
+            });
+
+            StringAssert.AreEqual(originalJson, oldFoo.ToString());
+
+            oldFoo.Merge(newFoo, new JsonMergeSettings
+            {
+                MergeNullValueHandling = MergeNullValueHandling.Merge
+            });
+
+            StringAssert.AreEqual(newJson, newFoo.ToString());
+        }
+
+        [Test]
+        public void MergeNullValueHandling_Object()
+        {
+            string originalJson = @"{
+  ""Bar"": {}
+}";
+            string newJson = @"{
+  ""Bar"": null
+}";
+
+            JObject oldFoo = JObject.Parse(originalJson);
+            JObject newFoo = JObject.Parse(newJson);
+
+            oldFoo.Merge(newFoo, new JsonMergeSettings
+            {
+                MergeNullValueHandling = MergeNullValueHandling.Ignore
+            });
+
+            StringAssert.AreEqual(originalJson, oldFoo.ToString());
+
+            oldFoo.Merge(newFoo, new JsonMergeSettings
+            {
+                MergeNullValueHandling = MergeNullValueHandling.Merge
+            });
+
+            StringAssert.AreEqual(newJson, newFoo.ToString());
+        }
+
+        public class Foo
+        {
+            public IEnumerable<string> Bar { get; set; }
+        }
     }
 }
\ No newline at end of file
diff --git a/Src/Newtonsoft.Json/Linq/JObject.cs b/Src/Newtonsoft.Json/Linq/JObject.cs
index 55e13d75..b9098ab1 100644
--- a/Src/Newtonsoft.Json/Linq/JObject.cs
+++ b/Src/Newtonsoft.Json/Linq/JObject.cs
@@ -190,17 +190,13 @@ namespace Newtonsoft.Json.Linq
                 else if (contentItem.Value != null)
                 {
                     JContainer existingContainer = existingProperty.Value as JContainer;
-                    if (existingContainer == null)
+                    if (existingContainer == null || existingContainer.Type != contentItem.Value.Type)
                     {
                         if (contentItem.Value.Type != JTokenType.Null || settings?.MergeNullValueHandling == MergeNullValueHandling.Merge)
                         {
                             existingProperty.Value = contentItem.Value;
                         }
                     }
-                    else if (existingContainer.Type != contentItem.Value.Type)
-                    {
-                        existingProperty.Value = contentItem.Value;
-                    }
                     else
                     {
                         existingContainer.Merge(contentItem.Value, settings);