Enable nullable reference types and apply notnull constraints to messaging interfaces, implementations, and unit tests.

Author: darthsharp

source/Reactive/CreativeCoders.Reactive.Messaging/CreativeCoders.Reactive.Messaging.csproj

@@ -3,6 +3,7 @@
     <PropertyGroup>
         <OutputType>Library</OutputType>
         <Description>Simple message topic implementation based on Reactive.net</Description>
+        <Nullable>enable</Nullable>
     </PropertyGroup>
 
     <ItemGroup>

source/Reactive/CreativeCoders.Reactive.Messaging/IMessageTopic.cs

@@ -7,9 +7,12 @@ namespace CreativeCoders.Reactive.Messaging;
 [PublicAPI]
 public interface IMessageTopic
 {
-    void Publish<TMessage>(TMessage message);
+    void Publish<TMessage>(TMessage message)
+        where TMessage : notnull;
 
-    IObservable<TMessage> Register<TMessage>();
+    IObservable<TMessage> Register<TMessage>()
+        where TMessage : notnull;
 
-    IObservable<TMessage> Register<TMessage>(IScheduler scheduler);
+    IObservable<TMessage> Register<TMessage>(IScheduler scheduler)
+        where TMessage : notnull;
 }

source/Reactive/CreativeCoders.Reactive.Messaging/IMessageTopicGeneric.cs

@@ -6,6 +6,7 @@ namespace CreativeCoders.Reactive.Messaging;
 
 [PublicAPI]
 public interface IMessageTopic<TMessage>
+    where TMessage : notnull
 {
     void Publish(TMessage message);
 

source/Reactive/CreativeCoders.Reactive.Messaging/MessageTopic.cs

@@ -18,13 +18,15 @@ public MessageTopic()
     }
 
     public void Publish<TMessage>(TMessage message)
+        where TMessage : notnull
     {
         Ensure.IsNotNull(message);
 
         _messageSubject.OnNext(message);
     }
 
     public IObservable<TMessage> Register<TMessage>()
+        where TMessage : notnull
     {
         var registration = _messageSubject
             .OfType<TMessage>()
@@ -35,6 +37,7 @@ public IObservable<TMessage> Register<TMessage>()
     }
 
     public IObservable<TMessage> Register<TMessage>(IScheduler scheduler)
+        where TMessage : notnull
     {
         Ensure.IsNotNull(scheduler);
 

source/Reactive/CreativeCoders.Reactive.Messaging/MessageTopicGeneric.cs

@@ -7,6 +7,7 @@
 namespace CreativeCoders.Reactive.Messaging;
 
 public class MessageTopic<TMessage> : IMessageTopic<TMessage>
+    where TMessage : notnull
 {
     private readonly ISubject<TMessage> _messageSubject;
 

tests/CreativeCoders.Reactive.UnitTests/CreativeCoders.Reactive.UnitTests.csproj

@@ -2,6 +2,7 @@
 
     <PropertyGroup>
         <OutputType>Library</OutputType>
+        <Nullable>enable</Nullable>
     </PropertyGroup>
 
     <ItemGroup>

tests/CreativeCoders.Reactive.UnitTests/MessageTopicGenericTests.cs

@@ -20,15 +20,15 @@ public void PublishTest()
 
         topic.Publish("Test");
 
-        Assert.Throws<ArgumentNullException>(() => topic.Publish(null));
+        Assert.Throws<ArgumentNullException>(() => topic.Publish(null!));
     }
 
     [Fact]
     public void RegisterTest()
     {
         var topic = new MessageTopic<object>();
 
-        object msgPublished = null;
+        object? msgPublished = null;
 
         topic.Register().Subscribe(o => msgPublished = o);
 
@@ -44,7 +44,7 @@ public void PublishTestDifferentMessageTypesWithScheduler()
     {
         var topic = new MessageTopic<object>();
 
-        object msgPublished = null;
+        object? msgPublished = null;
         var strPublished = false;
 
         topic.Register(Scheduler.Immediate).Subscribe(o => msgPublished = o);
@@ -70,7 +70,7 @@ public void PublishTestDifferentMessageTypes()
     {
         var topic = new MessageTopic<object>();
 
-        object msgPublished = null;
+        object? msgPublished = null;
         var strPublished = false;
 
         topic.Register().Subscribe(o => msgPublished = o);
@@ -96,15 +96,15 @@ public void PublishTestBeforeRegisterGeneric()
     {
         var topic = new MessageTopic<object>();
 
-        object objPublished = null;
+        object? objPublished = null;
 
         topic.Register<object>().Subscribe(o => objPublished = o);
 
         var obj = new object();
 
         topic.Publish(obj);
 
-        object secondObjPublished = null;
+        object? secondObjPublished = null;
 
         topic.Register<object>().Subscribe(o => secondObjPublished = o);
 
@@ -125,15 +125,15 @@ public void PublishTestBeforeRegister()
     {
         var topic = new MessageTopic<object>();
 
-        object objPublished = null;
+        object? objPublished = null;
 
         topic.Register().Subscribe(o => objPublished = o);
 
         var obj = new object();
 
         topic.Publish(obj);
 
-        object secondObjPublished = null;
+        object? secondObjPublished = null;
 
         topic.Register().Subscribe(o => secondObjPublished = o);
 

tests/CreativeCoders.Reactive.UnitTests/MessageTopicTests.cs

@@ -20,15 +20,15 @@ public void PublishTest()
 
         topic.Publish("Test");
 
-        Assert.Throws<ArgumentNullException>(() => topic.Publish<object>(null));
+        Assert.Throws<ArgumentNullException>(() => topic.Publish<object>(null!));
     }
 
     [Fact]
     public void RegisterTest()
     {
         var topic = new MessageTopic();
 
-        object msgPublished = null;
+        object? msgPublished = null;
 
         topic
             .Register<object>()
@@ -46,7 +46,7 @@ public void RegisterTestScheduler()
     {
         var topic = new MessageTopic();
 
-        object msgPublished = null;
+        object? msgPublished = null;
 
         topic
             .Register<object>(Scheduler.Immediate)
@@ -64,7 +64,7 @@ public void PublishTestDifferentMessageTypes()
     {
         var topic = new MessageTopic();
 
-        object msgPublished = null;
+        object? msgPublished = null;
         var strPublished = false;
 
         topic.Register<object>()
@@ -92,15 +92,15 @@ public void PublishTestBeforeRegister()
     {
         var topic = new MessageTopic();
 
-        object objPublished = null;
+        object? objPublished = null;
 
         topic.Register<object>().Subscribe(o => objPublished = o);
 
         var obj = new object();
 
         topic.Publish(obj);
 
-        object secondObjPublished = null;
+        object? secondObjPublished = null;
 
         topic.Register<object>().Subscribe(o => secondObjPublished = o);