feature resolvers changed to allow registration of null with a value type

src/Splat.Autofac.Tests/Splat.Autofac.Tests.csproj

@@ -6,6 +6,7 @@
     <IsPackable>false</IsPackable>
     <NoWarn>$(NoWarn);1591;CA1707;SA1633;CA2000</NoWarn>
     <LangVersion>latest</LangVersion>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

src/Splat.Autofac/AutofacDependencyResolver.cs

@@ -50,7 +50,7 @@ public AutofacDependencyResolver(ContainerBuilder builder)
         }
 
         /// <inheritdoc />
-        public virtual object? GetService(Type serviceType, string? contract = null)
+        public virtual object GetService(Type serviceType, string? contract = null)
         {
             lock (_lockObject)
             {
@@ -126,14 +126,14 @@ public bool HasRegistration(Type serviceType, string? contract = null)
         ///     Register a function with the resolver which will generate a object
         ///     for the specified service type.
         ///     Optionally a contract can be registered which will indicate
-        ///     that that registration will only work with that contract.
+        ///     that registration will only work with that contract.
         ///     Most implementations will use a stack based approach to allow for multiple items to be registered.
         /// </summary>
         /// <param name="factory">The factory function which generates our object.</param>
         /// <param name="serviceType">The type which is used for the registration.</param>
         /// <param name="contract">A optional contract value which will indicates to only generate the value if this contract is specified.</param>
         [Obsolete("Because Autofac 5+ containers are immutable, this method should not be used by the end-user.")]
-        public virtual void Register(Func<object> factory, Type serviceType, string? contract = null)
+        public virtual void Register(Func<object?> factory, Type serviceType, string? contract = null)
         {
             lock (_lockObject)
             {
@@ -147,21 +147,21 @@ public virtual void Register(Func<object> factory, Type serviceType, string? con
                 // Second to child lifetimes in a temporary container, that is used only to satisfy ReactiveUI dependencies.
                 if (contract is null || string.IsNullOrWhiteSpace(contract))
                 {
-                    _builder.Register(_ => factory())
+                    _builder.Register(_ => factory()!)
                         .As(serviceType)
                         .AsImplementedInterfaces();
                     _internalLifetimeScope = _internalLifetimeScope.BeginLifetimeScope(internalBuilder =>
-                        internalBuilder.Register(_ => factory())
+                        internalBuilder.Register(_ => factory()!)
                             .As(serviceType)
                             .AsImplementedInterfaces());
                 }
                 else
                 {
-                    _builder.Register(_ => factory())
+                    _builder.Register(_ => factory()!)
                         .Named(contract, serviceType)
                         .AsImplementedInterfaces();
                     _internalLifetimeScope = _internalLifetimeScope.BeginLifetimeScope(internalBuilder =>
-                        internalBuilder.Register(_ => factory())
+                        internalBuilder.Register(_ => factory()!)
                             .Named(contract, serviceType)
                             .AsImplementedInterfaces());
                 }
@@ -225,19 +225,19 @@ protected virtual void Dispose(bool disposing)
             }
         }
 
-        private object? Resolve(Type serviceType, string? contract)
+        private object Resolve(Type serviceType, string? contract)
         {
-            object? serviceInstance;
+            object serviceInstance;
 
             var lifeTimeScope = _lifetimeScope ?? _internalLifetimeScope;
 
             if (contract is null || string.IsNullOrWhiteSpace(contract))
             {
-                lifeTimeScope.TryResolve(serviceType, out serviceInstance);
+                lifeTimeScope.TryResolve(serviceType, out serviceInstance!);
             }
             else
             {
-                lifeTimeScope.TryResolveNamed(contract, serviceType, out serviceInstance);
+                lifeTimeScope.TryResolveNamed(contract, serviceType, out serviceInstance!);
             }
 
             return serviceInstance;

src/Splat.Tests/Mocks/DummyObjectClass1.cs → src/Splat.Common.Test/DummyObjectClass1.cs

@@ -8,7 +8,7 @@ namespace Splat.Tests.Mocks
     /// <summary>
     /// A dummy class used during Locator testing.
     /// </summary>
-    internal class DummyObjectClass1 : IDummyInterface
+    public class DummyObjectClass1 : IDummyInterface
     {
     }
 }

src/Splat.Tests/Mocks/DummyObjectClass2.cs → src/Splat.Common.Test/DummyObjectClass2.cs

@@ -8,7 +8,7 @@ namespace Splat.Tests.Mocks
     /// <summary>
     /// A dummy class used during Locator testing.
     /// </summary>
-    internal class DummyObjectClass2 : IDummyInterface
+    public class DummyObjectClass2 : IDummyInterface
     {
     }
 }

src/Splat.Tests/Mocks/DummyObjectClass3.cs → src/Splat.Common.Test/DummyObjectClass3.cs

@@ -8,7 +8,7 @@ namespace Splat.Tests.Mocks
     /// <summary>
     /// A dummy class used during Locator testing.
     /// </summary>
-    internal class DummyObjectClass3 : IDummyInterface
+    public class DummyObjectClass3 : IDummyInterface
     {
     }
 }

src/Splat.Tests/Mocks/IDummyInterface.cs → src/Splat.Common.Test/IDummyInterface.cs

@@ -8,7 +8,7 @@ namespace Splat.Tests.Mocks
     /// <summary>
     /// A dummy interface used during Locator testing.
     /// </summary>
-    internal interface IDummyInterface
+    public interface IDummyInterface
     {
     }
 }

src/Splat.Common.Test/IViewFor.cs

@@ -6,17 +6,19 @@
 namespace Splat.Common.Test
 {
 #pragma warning disable SA1402 // File may only contain a single type
+
     /// <summary>
     /// Represents a view bound to a view model.
     /// </summary>
     /// <typeparam name="T">The view model type.</typeparam>
     /// <seealso cref="Splat.Common.Test.IViewFor" />
     public interface IViewFor<T> : IViewFor
+        where T : class
     {
         /// <summary>
         /// Gets or sets the view model.
         /// </summary>
-        new T ViewModel { get; set; }
+        new T? ViewModel { get; set; }
     }
 
     /// <summary>
@@ -28,7 +30,8 @@ public interface IViewFor
         /// <summary>
         /// Gets or sets the view model.
         /// </summary>
-        object ViewModel { get; set; }
+        object? ViewModel { get; set; }
     }
+
 #pragma warning restore SA1402 // File may only contain a single type
 }

src/Splat.Common.Test/Splat.Common.Test.csproj

@@ -4,6 +4,7 @@
     <TargetFrameworks>netstandard2.0;net5.0</TargetFrameworks>
     <NoWarn>$(NoWarn);CA2000</NoWarn>
     <LangVersion>latest</LangVersion>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
 </Project>

src/Splat.Common.Test/ViewOne.cs

@@ -12,13 +12,13 @@ namespace Splat.Common.Test
     public class ViewOne : IViewFor<ViewModelOne>
     {
         /// <inheritdoc />
-        object IViewFor.ViewModel
+        object? IViewFor.ViewModel
         {
             get => ViewModel;
-            set => ViewModel = (ViewModelOne)value;
+            set => ViewModel = (ViewModelOne?)value;
         }
 
         /// <inheritdoc />
-        public ViewModelOne ViewModel { get; set; }
+        public ViewModelOne? ViewModel { get; set; }
     }
 }

src/Splat.Common.Test/ViewTwo.cs

@@ -12,13 +12,13 @@ namespace Splat.Common.Test
     public class ViewTwo : IViewFor<ViewModelTwo>
     {
         /// <inheritdoc />
-        object IViewFor.ViewModel
+        object? IViewFor.ViewModel
         {
             get => ViewModel;
-            set => ViewModel = (ViewModelTwo)value;
+            set => ViewModel = (ViewModelTwo?)value;
         }
 
         /// <inheritdoc />
-        public ViewModelTwo ViewModel { get; set; }
+        public ViewModelTwo? ViewModel { get; set; }
     }
 }

src/Splat.Drawing.Tests/BitmapLoaderTests.cs

@@ -11,6 +11,7 @@
 using Xunit;
 
 #if !NETSTANDARD2_0
+
 namespace Splat.Tests
 {
     /// <summary>
@@ -100,9 +101,10 @@ private static Stream GetStream(string imageName)
             return Android.App.Application.Context.Assets.Open(imageName);
 #else
             var assembly = Assembly.GetExecutingAssembly();
-            return assembly.GetManifestResourceStream(imageName);
+            return assembly.GetManifestResourceStream(imageName)!;
 #endif
         }
     }
 }
+
 #endif

src/Splat.Drawing.Tests/Colors/SplatColorTests.cs

@@ -55,7 +55,7 @@ private static IEnumerable<object[]> GetEnumAsTestTheory()
             var results = new List<object[]>(values.Length);
             foreach (var value in values)
             {
-                results.Add(new[] { value });
+                results.Add(new[] { value! });
             }
 
             return results;

src/Splat.Drawing.Tests/Splat.Drawing.Tests.csproj

@@ -5,6 +5,7 @@
     <IsPackable>false</IsPackable>
     <NoWarn>$(NoWarn);1591;CA1707;SA1633;CA2000;CA1034</NoWarn>
     <LangVersion>latest</LangVersion>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(OS)' == 'Windows_NT' ">

src/Splat.DryIoc.Tests/Splat.DryIoc.Tests.csproj

@@ -4,6 +4,7 @@
     <TargetFrameworks>net5.0;netcoreapp3.1</TargetFrameworks>
     <NoWarn>$(NoWarn);1591;CA1707;SA1633;CA2000</NoWarn>
     <LangVersion>latest</LangVersion>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

src/Splat.DryIoc/DryIocDependencyResolver.cs

@@ -29,10 +29,10 @@ public DryIocDependencyResolver(IContainer? container = null)
         }
 
         /// <inheritdoc />
-        public virtual object? GetService(Type serviceType, string? contract = null) =>
+        public virtual object GetService(Type serviceType, string? contract = null) =>
             string.IsNullOrEmpty(contract)
-                ? _container.ResolveMany(serviceType).LastOrDefault()
-                : _container.ResolveMany(serviceType, serviceKey: contract).LastOrDefault();
+                ? _container.ResolveMany(serviceType).LastOrDefault()!
+                : _container.ResolveMany(serviceType, serviceKey: contract).LastOrDefault()!;
 
         /// <inheritdoc />
         public virtual IEnumerable<object> GetServices(Type serviceType, string? contract = null) =>
@@ -61,7 +61,7 @@ public bool HasRegistration(Type serviceType, string? contract = null)
         }
 
         /// <inheritdoc />
-        public virtual void Register(Func<object> factory, Type serviceType, string? contract = null)
+        public virtual void Register(Func<object?> factory, Type serviceType, string? contract = null)
         {
             if (factory is null)
             {

src/Splat.Microsoft.Extensions.DependencyInjection.Tests/ContainerWrapper.cs

@@ -9,25 +9,17 @@ internal class ContainerWrapper
     {
         private IServiceProvider _serviceProvider;
 
+#pragma warning disable CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider declaring as nullable.
+
         public ContainerWrapper()
+#pragma warning restore CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider declaring as nullable.
         {
             ServiceCollection.UseMicrosoftDependencyResolver();
         }
 
         public IServiceCollection ServiceCollection { get; } = new ServiceCollection();
 
-        public IServiceProvider ServiceProvider
-        {
-            get
-            {
-                if (_serviceProvider is null)
-                {
-                    _serviceProvider = ServiceCollection.BuildServiceProvider();
-                }
-
-                return _serviceProvider;
-            }
-        }
+        public IServiceProvider ServiceProvider => _serviceProvider ??= ServiceCollection.BuildServiceProvider();
 
         public void BuildAndUse() => ServiceProvider.UseMicrosoftDependencyResolver();
     }

src/Splat.Microsoft.Extensions.DependencyInjection.Tests/DependencyResolverTests.cs

@@ -10,7 +10,7 @@
 using Microsoft.Extensions.DependencyInjection;
 
 using Splat.Common.Test;
-
+using Splat.NLog;
 using Xunit;
 
 namespace Splat.Microsoft.Extensions.DependencyInjection.Tests
@@ -147,5 +147,28 @@ public void MicrosoftDependencyResolver_Should_Throw_If_Attempt_Registration_Aft
 
             result.Should().BeOfType<InvalidOperationException>();
         }
+
+        /// <summary>
+        /// Tests to ensure NLog registers correctly with different service locators.
+        /// Based on issue reported in #553.
+        /// </summary>
+        [Fact]
+        public void ILogManager_Resolvable()
+        {
+            var wrapper = new ContainerWrapper();
+            var services = wrapper.ServiceCollection;
+
+            // Setup NLog for Logging (doesn't matter if I actually configure NLog or not)
+            var funcLogManager = new FuncLogManager(type => new NLogLogger(LogResolver.Resolve(type)));
+            services.AddSingleton<ILogManager>(funcLogManager);
+
+            wrapper.BuildAndUse();
+
+            // Get the ILogManager instance.
+            ILogManager lm = Locator.Current.GetService<ILogManager>();
+
+            var mgr = lm.GetLogger<NLogLogger>();
+            Assert.NotNull(mgr);
+        }
     }
 }

src/Splat.Microsoft.Extensions.DependencyInjection.Tests/MicrosoftDependencyResolverTests.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Text;
+using Microsoft.Extensions.DependencyInjection;
 using Splat.Microsoft.Extensions.DependencyInjection;
 using Xunit;
 
@@ -21,16 +22,16 @@ public void Can_Register_And_Resolve_Null_Types()
         {
             var resolver = GetDependencyResolver();
             var foo = 5;
-            resolver.Register(() => foo, null);
+            resolver.Register(() => foo, null!);
 
-            var value = resolver.GetService(null);
+            var value = resolver.GetService(null!);
             Assert.Equal(foo, value);
 
             var bar = 4;
             var contract = "foo";
-            resolver.Register(() => bar, null, contract);
+            resolver.Register(() => bar, null!, contract);
 
-            value = resolver.GetService(null, contract);
+            value = resolver.GetService(null!, contract);
             Assert.Equal(bar, value);
         }
 

src/Splat.Microsoft.Extensions.DependencyInjection.Tests/Splat.Microsoft.Extensions.DependencyInjection.Tests.csproj

@@ -5,9 +5,11 @@
     <NoWarn>$(NoWarn);1591;CA1707;SA1633;CA2000</NoWarn>
     <IsPackable>false</IsPackable>
     <LangVersion>latest</LangVersion>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>
+    <Compile Include="..\Splat.NLog\LogResolver.cs" Link="LogResolver.cs" />
     <Compile Include="..\Splat.Tests\ServiceLocation\BaseDependencyResolverTests.cs" Link="BaseDependencyResolverTests.cs" />
   </ItemGroup>