-Added Required.DisallowNull

Build/build.ps1

@@ -2,7 +2,7 @@
   $zipFileName = "Json80r1.zip"
   $majorVersion = "8.0"
   $majorWithReleaseVersion = "8.0.1"
-  $nugetPrelease = "beta2"
+  $nugetPrelease = "beta3"
   $version = GetVersion $majorWithReleaseVersion
   $packageId = "Newtonsoft.Json"
   $signAssemblies = $false

Src/Newtonsoft.Json.Tests/Serialization/JsonSerializerTest.cs

@@ -237,6 +237,22 @@ namespace Newtonsoft.Json.Tests.Serialization
             }, "Required property 'RequiredProperty' expects a value but got null. Path '', line 1, position 21.");
         }
 
+        [Test]
+        public void CoercedEmptyStringWithRequired_DisallowNull()
+        {
+            ExceptionAssert.Throws<JsonSerializationException>(() =>
+            {
+                JsonConvert.DeserializeObject<Binding_DisallowNull>("{requiredProperty:''}");
+            }, "Required property 'RequiredProperty' expects a non-null value. Path '', line 1, position 21.");
+        }
+
+        [Test]
+        public void DisallowNull_NoValue()
+        {
+            Binding_DisallowNull o = JsonConvert.DeserializeObject<Binding_DisallowNull>("{}");
+            Assert.IsNull(o.RequiredProperty);
+        }
+
         [Test]
         public void CoercedEmptyStringWithRequiredConstructor()
         {
@@ -252,6 +268,46 @@ namespace Newtonsoft.Json.Tests.Serialization
             public Binding RequiredProperty { get; set; }
         }
 
+        public class Binding_DisallowNull
+        {
+            [JsonProperty(Required = Required.DisallowNull)]
+            public Binding RequiredProperty { get; set; }
+        }
+
+        [Test]
+        public void Serialize_Required_DisallowedNull()
+        {
+            ExceptionAssert.Throws<JsonSerializationException>(() =>
+            {
+                JsonConvert.SerializeObject(new Binding_DisallowNull());
+            }, "Cannot write a null value for property 'RequiredProperty'. Property requires a non-null value. Path ''.");
+        }
+
+        [Test]
+        public void Serialize_Required_DisallowedNull_NullValueHandlingIgnore()
+        {
+            string json = JsonConvert.SerializeObject(new Binding_DisallowNull(), new JsonSerializerSettings
+            {
+                NullValueHandling = NullValueHandling.Ignore
+            });
+            Assert.AreEqual("{}", json);
+        }
+
+        [JsonObject(ItemRequired = Required.DisallowNull)]
+        public class DictionaryWithNoNull
+        {
+            public string Name { get; set; }
+        }
+
+        [Test]
+        public void Serialize_ItemRequired_DisallowedNull()
+        {
+            ExceptionAssert.Throws<JsonSerializationException>(() =>
+            {
+                JsonConvert.SerializeObject(new DictionaryWithNoNull());
+            }, "Cannot write a null value for property 'Name'. Property requires a non-null value. Path ''.");
+        }
+
         public class DictionaryKeyContractResolver : DefaultContractResolver
         {
             protected override string ResolveDictionaryKey(string dictionaryKey)

Src/Newtonsoft.Json/Required.cs

@@ -43,6 +43,11 @@ namespace Newtonsoft.Json
         /// <summary>
         /// The property must be defined in JSON and cannot be a null value.
         /// </summary>
-        Always = 2
+        Always = 2,
+
+        /// <summary>
+        /// The property is not required but it cannot be a null value.
+        /// </summary>
+        DisallowNull = 3
     }
 }

Src/Newtonsoft.Json/Serialization/JsonSerializerInternalReader.cs

@@ -2193,7 +2193,9 @@ namespace Newtonsoft.Json.Serialization
                             {
                                 case PropertyPresence.None:
                                     if (resolvedRequired == Required.AllowNull || resolvedRequired == Required.Always)
+                                    {
                                         throw JsonSerializationException.Create(reader, "Required property '{0}' not found in JSON.".FormatWith(CultureInfo.InvariantCulture, property.PropertyName));
+                                    }
 
                                     if (!property.Ignored)
                                     {
@@ -2206,7 +2208,13 @@ namespace Newtonsoft.Json.Serialization
                                     break;
                                 case PropertyPresence.Null:
                                     if (resolvedRequired == Required.Always)
+                                    {
                                         throw JsonSerializationException.Create(reader, "Required property '{0}' expects a value but got null.".FormatWith(CultureInfo.InvariantCulture, property.PropertyName));
+                                    }
+                                    if (resolvedRequired == Required.DisallowNull)
+                                    {
+                                        throw JsonSerializationException.Create(reader, "Required property '{0}' expects a non-null value.".FormatWith(CultureInfo.InvariantCulture, property.PropertyName));
+                                    }
                                     break;
                             }
                         }

Src/Newtonsoft.Json/Serialization/JsonSerializerInternalWriter.cs

@@ -490,7 +490,13 @@ namespace Newtonsoft.Json.Serialization
                         JsonObjectContract objectContract = contract as JsonObjectContract;
                         Required resolvedRequired = property._required ?? ((objectContract != null) ? objectContract.ItemRequired : null) ?? Required.Default;
                         if (resolvedRequired == Required.Always)
+                        {
                             throw JsonSerializationException.Create(null, writer.ContainerPath, "Cannot write a null value for property '{0}'. Property requires a value.".FormatWith(CultureInfo.InvariantCulture, property.PropertyName), null);
+                        }
+                        if (resolvedRequired == Required.DisallowNull)
+                        {
+                            throw JsonSerializationException.Create(null, writer.ContainerPath, "Cannot write a null value for property '{0}'. Property requires a non-null value.".FormatWith(CultureInfo.InvariantCulture, property.PropertyName), null);
+                        }
                     }
 
                     return true;