From cf1e58ae9bb6898e72736c1ba535899c06cd3aa5 Mon Sep 17 00:00:00 2001
From: SteveCollie <steve.collie@finbourne.com>
Date: Mon, 21 Sep 2020 18:23:31 +0100
Subject: [PATCH 1/2] Improve handling a datetime field in a sub-type

---
 JsonSubTypes.Tests/DatesTests.cs | 34 ++++++++++++++++++++++++++++++++
 JsonSubTypes/JsonSubtypes.cs     |  5 +++++
 2 files changed, 39 insertions(+)
 create mode 100644 JsonSubTypes.Tests/DatesTests.cs

diff --git a/JsonSubTypes.Tests/DatesTests.cs b/JsonSubTypes.Tests/DatesTests.cs
new file mode 100644
index 0000000..beb4025
--- /dev/null
+++ b/JsonSubTypes.Tests/DatesTests.cs
@@ -0,0 +1,34 @@
+using System;
+using Newtonsoft.Json;
+using NUnit.Framework;
+
+namespace JsonSubTypes.Tests
+{
+    [TestFixture]
+    public class DatesTest
+    {
+        [JsonConverter(typeof(JsonSubtypes), nameof(SubTypeClass.Discriminator))]
+        public abstract class MainClass
+        {
+        }
+
+        public class SubTypeClass : MainClass
+        {
+            public string Discriminator => "SubTypeClass";
+
+            public DateTimeOffset? Date { get; set; }
+        }
+
+        [Test]
+        public void DeserializingSubTypeWithDateParsesCorrectly()
+        {
+            var json = "{ \"Discriminator\": \"MainClass\", \"Date\": \"2020-06-28T00:00:00.00000+00:00\" }";
+
+            var obj = JsonConvert.DeserializeObject<SubTypeClass>(json);
+
+            Assert.That(obj, Is.Not.Null);
+            Assert.That(obj.Date.HasValue, Is.True);
+            Assert.That(obj.Date.Value.Offset, Is.EqualTo(TimeSpan.Zero));
+        }
+    }
+}
diff --git a/JsonSubTypes/JsonSubtypes.cs b/JsonSubTypes/JsonSubtypes.cs
index 296d302..c4f6cec 100644
--- a/JsonSubTypes/JsonSubtypes.cs
+++ b/JsonSubTypes/JsonSubtypes.cs
@@ -201,7 +201,12 @@ private static Type GetElementType(Type arrayOrGenericContainer)
 
         private object ReadObject(JsonReader reader, Type objectType, JsonSerializer serializer)
         {
+            // I would prefer to create a new reader, but can't work out how to
+            // This seems a reasonable alternative - https://github.com/JamesNK/Newtonsoft.Json/issues/1605#issuecomment-602673364
+            var savedDateParseSettings = reader.DateParseHandling;
+            reader.DateParseHandling = DateParseHandling.None;
             var jObject = JObject.Load(reader);
+            reader.DateParseHandling = savedDateParseSettings;
 
             var targetType = GetType(jObject, objectType, serializer) ?? objectType;
 

From 2b754700aa3e675f23638cc8e57a5f02cf06ff67 Mon Sep 17 00:00:00 2001
From: Emmanuel Counasse <manuc66@gmail.com>
Date: Wed, 23 Sep 2020 23:54:07 +0200
Subject: [PATCH 2/2] Update DatesTests.cs

Update test to use JsonSubtypes converter
---
 JsonSubTypes.Tests/DatesTests.cs | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/JsonSubTypes.Tests/DatesTests.cs b/JsonSubTypes.Tests/DatesTests.cs
index beb4025..65c6c35 100644
--- a/JsonSubTypes.Tests/DatesTests.cs
+++ b/JsonSubTypes.Tests/DatesTests.cs
@@ -8,6 +8,7 @@ namespace JsonSubTypes.Tests
     public class DatesTest
     {
         [JsonConverter(typeof(JsonSubtypes), nameof(SubTypeClass.Discriminator))]
+        [JsonSubtypes.KnownSubType(typeof(SubTypeClass), "SubTypeClass")]
         public abstract class MainClass
         {
         }
@@ -22,13 +23,14 @@ public class SubTypeClass : MainClass
         [Test]
         public void DeserializingSubTypeWithDateParsesCorrectly()
         {
-            var json = "{ \"Discriminator\": \"MainClass\", \"Date\": \"2020-06-28T00:00:00.00000+00:00\" }";
+            var json = "{ \"Discriminator\": \"SubTypeClass\", \"Date\": \"2020-06-28T00:00:00.00000+00:00\" }";
 
-            var obj = JsonConvert.DeserializeObject<SubTypeClass>(json);
+            var obj = JsonConvert.DeserializeObject<MainClass>(json);
 
             Assert.That(obj, Is.Not.Null);
-            Assert.That(obj.Date.HasValue, Is.True);
-            Assert.That(obj.Date.Value.Offset, Is.EqualTo(TimeSpan.Zero));
+            Assert.That(obj, Is.InstanceOf<SubTypeClass>());
+            Assert.That(((SubTypeClass)obj).Date.HasValue, Is.True);
+            Assert.That(((SubTypeClass)obj).Date.Value.Offset, Is.EqualTo(TimeSpan.Zero));
         }
     }
 }