Fix #1984

Src/Newtonsoft.Json.Tests/Issues/Issue1984.cs

@@ -0,0 +1,64 @@
+#region License
+// Copyright (c) 2007 James Newton-King
+//
+// Permission is hereby granted, free of charge, to any person
+// obtaining a copy of this software and associated documentation
+// files (the "Software"), to deal in the Software without
+// restriction, including without limitation the rights to use,
+// copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following
+// conditions:
+//
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+// OTHER DEALINGS IN THE SOFTWARE.
+#endregion
+
+#if !(NET20 || NET35 || NET40)
+using System.Collections;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+#if DNXCORE50
+using Xunit;
+using Test = Xunit.FactAttribute;
+using Assert = Newtonsoft.Json.Tests.XUnitAssert;
+#else
+using NUnit.Framework;
+#endif
+
+namespace Newtonsoft.Json.Tests.Issues
+{
+    public class Issue1984
+    {
+        [Test]
+        public void Test_NullValue()
+        {
+            var actual = JsonConvert.DeserializeObject<A>("{ Values: null}");
+            Assert.IsNotNull(actual);
+            Assert.IsNull(actual.Values);
+        }
+
+        [Test]
+        public void Test_WithoutValue()
+        {
+            var actual = JsonConvert.DeserializeObject<A>("{ }");
+            Assert.IsNotNull(actual);
+            Assert.IsNull(actual.Values);
+        }
+        
+        public class A
+        {
+            public ImmutableArray<string>? Values { get; set; }
+        }
+    }
+}
+#endif

Src/Newtonsoft.Json/Serialization/DefaultContractResolver.cs

@@ -1216,7 +1216,7 @@ namespace Newtonsoft.Json.Serialization
 
             if (typeof(IEnumerable).IsAssignableFrom(t))
             {
-                return CreateArrayContract(t);
+                return CreateArrayContract(objectType);
             }
 
             if (CanConvertToString(t))

Src/Newtonsoft.Json/Serialization/JsonArrayContract.cs

@@ -115,6 +115,7 @@ namespace Newtonsoft.Json.Serialization
         public JsonArrayContract(Type underlyingType)
             : base(underlyingType)
         {
+            var t = ReflectionUtils.EnsureNotByRefType(ReflectionUtils.EnsureNotNullableType(underlyingType));
             ContractType = JsonContractType.Array;
             IsArray = CreatedType.IsArray;
 
@@ -130,58 +131,58 @@ namespace Newtonsoft.Json.Serialization
                 canDeserialize = true;
                 IsMultidimensionalArray = (IsArray && UnderlyingType.GetArrayRank() > 1);
             }
-            else if (typeof(IList).IsAssignableFrom(underlyingType))
+            else if (typeof(IList).IsAssignableFrom(t))
             {
-                if (ReflectionUtils.ImplementsGenericDefinition(underlyingType, typeof(ICollection<>), out _genericCollectionDefinitionType))
+                if (ReflectionUtils.ImplementsGenericDefinition(t, typeof(ICollection<>), out _genericCollectionDefinitionType))
                 {
                     CollectionItemType = _genericCollectionDefinitionType.GetGenericArguments()[0];
                 }
                 else
                 {
-                    CollectionItemType = ReflectionUtils.GetCollectionItemType(underlyingType);
+                    CollectionItemType = ReflectionUtils.GetCollectionItemType(t);
                 }
 
-                if (underlyingType == typeof(IList))
+                if (t == typeof(IList))
                 {
                     CreatedType = typeof(List<object>);
                 }
 
                 if (CollectionItemType != null)
                 {
-                    _parameterizedConstructor = CollectionUtils.ResolveEnumerableCollectionConstructor(underlyingType, CollectionItemType);
+                    _parameterizedConstructor = CollectionUtils.ResolveEnumerableCollectionConstructor(t, CollectionItemType);
                 }
 
-                IsReadOnlyOrFixedSize = ReflectionUtils.InheritsGenericDefinition(underlyingType, typeof(ReadOnlyCollection<>));
+                IsReadOnlyOrFixedSize = ReflectionUtils.InheritsGenericDefinition(t, typeof(ReadOnlyCollection<>));
                 canDeserialize = true;
             }
-            else if (ReflectionUtils.ImplementsGenericDefinition(underlyingType, typeof(ICollection<>), out _genericCollectionDefinitionType))
+            else if (ReflectionUtils.ImplementsGenericDefinition(t, typeof(ICollection<>), out _genericCollectionDefinitionType))
             {
                 CollectionItemType = _genericCollectionDefinitionType.GetGenericArguments()[0];
 
-                if (ReflectionUtils.IsGenericDefinition(underlyingType, typeof(ICollection<>))
-                    || ReflectionUtils.IsGenericDefinition(underlyingType, typeof(IList<>)))
+                if (ReflectionUtils.IsGenericDefinition(t, typeof(ICollection<>))
+                    || ReflectionUtils.IsGenericDefinition(t, typeof(IList<>)))
                 {
                     CreatedType = typeof(List<>).MakeGenericType(CollectionItemType);
                 }
 
 #if HAVE_ISET
-                if (ReflectionUtils.IsGenericDefinition(underlyingType, typeof(ISet<>)))
+                if (ReflectionUtils.IsGenericDefinition(t, typeof(ISet<>)))
                 {
                     CreatedType = typeof(HashSet<>).MakeGenericType(CollectionItemType);
                 }
 #endif
 
-                _parameterizedConstructor = CollectionUtils.ResolveEnumerableCollectionConstructor(underlyingType, CollectionItemType);
+                _parameterizedConstructor = CollectionUtils.ResolveEnumerableCollectionConstructor(t, CollectionItemType);
                 canDeserialize = true;
                 ShouldCreateWrapper = true;
             }
 #if HAVE_READ_ONLY_COLLECTIONS
-            else if (ReflectionUtils.ImplementsGenericDefinition(underlyingType, typeof(IReadOnlyCollection<>), out tempCollectionType))
+            else if (ReflectionUtils.ImplementsGenericDefinition(t, typeof(IReadOnlyCollection<>), out tempCollectionType))
             {
                 CollectionItemType = tempCollectionType.GetGenericArguments()[0];
 
-                if (ReflectionUtils.IsGenericDefinition(underlyingType, typeof(IReadOnlyCollection<>))
-                    || ReflectionUtils.IsGenericDefinition(underlyingType, typeof(IReadOnlyList<>)))
+                if (ReflectionUtils.IsGenericDefinition(t, typeof(IReadOnlyCollection<>))
+                    || ReflectionUtils.IsGenericDefinition(t, typeof(IReadOnlyList<>)))
                 {
                     CreatedType = typeof(ReadOnlyCollection<>).MakeGenericType(CollectionItemType);
                 }
@@ -190,14 +191,14 @@ namespace Newtonsoft.Json.Serialization
                 _parameterizedConstructor = CollectionUtils.ResolveEnumerableCollectionConstructor(CreatedType, CollectionItemType);
 
 #if HAVE_FSHARP_TYPES
-                StoreFSharpListCreatorIfNecessary(underlyingType);
+                StoreFSharpListCreatorIfNecessary(t);
 #endif
 
                 IsReadOnlyOrFixedSize = true;
                 canDeserialize = HasParameterizedCreatorInternal;
             }
 #endif
-            else if (ReflectionUtils.ImplementsGenericDefinition(underlyingType, typeof(IEnumerable<>), out tempCollectionType))
+            else if (ReflectionUtils.ImplementsGenericDefinition(t, typeof(IEnumerable<>), out tempCollectionType))
             {
                 CollectionItemType = tempCollectionType.GetGenericArguments()[0];
 
@@ -206,13 +207,13 @@ namespace Newtonsoft.Json.Serialization
                     CreatedType = typeof(List<>).MakeGenericType(CollectionItemType);
                 }
 
-                _parameterizedConstructor = CollectionUtils.ResolveEnumerableCollectionConstructor(underlyingType, CollectionItemType);
+                _parameterizedConstructor = CollectionUtils.ResolveEnumerableCollectionConstructor(t, CollectionItemType);
 
 #if HAVE_FSHARP_TYPES
-                StoreFSharpListCreatorIfNecessary(underlyingType);
+                StoreFSharpListCreatorIfNecessary(t);
 #endif
 
-                if (underlyingType.IsGenericType() && underlyingType.GetGenericTypeDefinition() == typeof(IEnumerable<>))
+                if (t.IsGenericType() && t.GetGenericTypeDefinition() == typeof(IEnumerable<>))
                 {
                     _genericCollectionDefinitionType = tempCollectionType;
 
@@ -252,7 +253,7 @@ namespace Newtonsoft.Json.Serialization
 #endif
 
             if (ImmutableCollectionsUtils.TryBuildImmutableForArrayContract(
-                underlyingType,
+                t,
                 CollectionItemType,
                 out Type immutableCreatedType,
                 out ObjectConstructor<object> immutableParameterizedCreator))