[Group 8] Enable nullable annotations for Microsoft.Extensions.Hosting

src/libraries/Microsoft.Extensions.Hosting/ref/Microsoft.Extensions.Hosting.cs

@@ -15,8 +15,8 @@ namespace Microsoft.Extensions.Hosting
 {
     public enum BackgroundServiceExceptionBehavior
     {
-        StopHost,
-        Ignore
+        StopHost = 0,
+        Ignore = 1,
     }
     public partial class ConsoleLifetimeOptions
     {
@@ -26,31 +26,31 @@ public ConsoleLifetimeOptions() { }
     public static partial class Host
     {
         public static Microsoft.Extensions.Hosting.HostApplicationBuilder CreateApplicationBuilder() { throw null; }
-        public static Microsoft.Extensions.Hosting.HostApplicationBuilder CreateApplicationBuilder(string[] args) { throw null; }
+        public static Microsoft.Extensions.Hosting.HostApplicationBuilder CreateApplicationBuilder(string[]? args) { throw null; }
         public static Microsoft.Extensions.Hosting.IHostBuilder CreateDefaultBuilder() { throw null; }
-        public static Microsoft.Extensions.Hosting.IHostBuilder CreateDefaultBuilder(string[] args) { throw null; }
+        public static Microsoft.Extensions.Hosting.IHostBuilder CreateDefaultBuilder(string[]? args) { throw null; }
     }
     public sealed partial class HostApplicationBuilder
     {
         public HostApplicationBuilder() { }
-        public HostApplicationBuilder(Microsoft.Extensions.Hosting.HostApplicationBuilderSettings settings) { }
-        public HostApplicationBuilder(string[] args) { }
+        public HostApplicationBuilder(Microsoft.Extensions.Hosting.HostApplicationBuilderSettings? settings) { }
+        public HostApplicationBuilder(string[]? args) { }
         public Microsoft.Extensions.Configuration.ConfigurationManager Configuration { get { throw null; } }
         public Microsoft.Extensions.Hosting.IHostEnvironment Environment { get { throw null; } }
         public Microsoft.Extensions.Logging.ILoggingBuilder Logging { get { throw null; } }
         public Microsoft.Extensions.DependencyInjection.IServiceCollection Services { get { throw null; } }
         public Microsoft.Extensions.Hosting.IHost Build() { throw null; }
-        public void ConfigureContainer<TContainerBuilder>(Microsoft.Extensions.DependencyInjection.IServiceProviderFactory<TContainerBuilder> factory, System.Action<TContainerBuilder> configure = null) where TContainerBuilder : notnull { }
+        public void ConfigureContainer<TContainerBuilder>(Microsoft.Extensions.DependencyInjection.IServiceProviderFactory<TContainerBuilder> factory, System.Action<TContainerBuilder>? configure = null) where TContainerBuilder : notnull { }
     }
     public sealed partial class HostApplicationBuilderSettings
     {
         public HostApplicationBuilderSettings() { }
-        public string ApplicationName { get { throw null; } set { } }
-        public string[] Args { get { throw null; } set { } }
-        public Microsoft.Extensions.Configuration.ConfigurationManager Configuration { get { throw null; } set { } }
-        public string ContentRootPath { get { throw null; } set { } }
+        public string? ApplicationName { get { throw null; } set { } }
+        public string[]? Args { get { throw null; } set { } }
+        public Microsoft.Extensions.Configuration.ConfigurationManager? Configuration { get { throw null; } set { } }
+        public string? ContentRootPath { get { throw null; } set { } }
         public bool DisableDefaults { get { throw null; } set { } }
-        public string EnvironmentName { get { throw null; } set { } }
+        public string? EnvironmentName { get { throw null; } set { } }
     }
     public partial class HostBuilder : Microsoft.Extensions.Hosting.IHostBuilder
     {
@@ -61,14 +61,14 @@ public HostBuilder() { }
         public Microsoft.Extensions.Hosting.IHostBuilder ConfigureContainer<TContainerBuilder>(System.Action<Microsoft.Extensions.Hosting.HostBuilderContext, TContainerBuilder> configureDelegate) { throw null; }
         public Microsoft.Extensions.Hosting.IHostBuilder ConfigureHostConfiguration(System.Action<Microsoft.Extensions.Configuration.IConfigurationBuilder> configureDelegate) { throw null; }
         public Microsoft.Extensions.Hosting.IHostBuilder ConfigureServices(System.Action<Microsoft.Extensions.Hosting.HostBuilderContext, Microsoft.Extensions.DependencyInjection.IServiceCollection> configureDelegate) { throw null; }
-        public Microsoft.Extensions.Hosting.IHostBuilder UseServiceProviderFactory<TContainerBuilder>(Microsoft.Extensions.DependencyInjection.IServiceProviderFactory<TContainerBuilder> factory) { throw null; }
-        public Microsoft.Extensions.Hosting.IHostBuilder UseServiceProviderFactory<TContainerBuilder>(System.Func<Microsoft.Extensions.Hosting.HostBuilderContext, Microsoft.Extensions.DependencyInjection.IServiceProviderFactory<TContainerBuilder>> factory) { throw null; }
+        public Microsoft.Extensions.Hosting.IHostBuilder UseServiceProviderFactory<TContainerBuilder>(Microsoft.Extensions.DependencyInjection.IServiceProviderFactory<TContainerBuilder> factory) where TContainerBuilder : notnull { throw null; }
+        public Microsoft.Extensions.Hosting.IHostBuilder UseServiceProviderFactory<TContainerBuilder>(System.Func<Microsoft.Extensions.Hosting.HostBuilderContext, Microsoft.Extensions.DependencyInjection.IServiceProviderFactory<TContainerBuilder>> factory) where TContainerBuilder : notnull { throw null; }
     }
     public static partial class HostingHostBuilderExtensions
     {
         public static Microsoft.Extensions.Hosting.IHostBuilder ConfigureAppConfiguration(this Microsoft.Extensions.Hosting.IHostBuilder hostBuilder, System.Action<Microsoft.Extensions.Configuration.IConfigurationBuilder> configureDelegate) { throw null; }
         public static Microsoft.Extensions.Hosting.IHostBuilder ConfigureContainer<TContainerBuilder>(this Microsoft.Extensions.Hosting.IHostBuilder hostBuilder, System.Action<TContainerBuilder> configureDelegate) { throw null; }
-        public static Microsoft.Extensions.Hosting.IHostBuilder ConfigureDefaults(this Microsoft.Extensions.Hosting.IHostBuilder builder, string[] args) { throw null; }
+        public static Microsoft.Extensions.Hosting.IHostBuilder ConfigureDefaults(this Microsoft.Extensions.Hosting.IHostBuilder builder, string[]? args) { throw null; }
         public static Microsoft.Extensions.Hosting.IHostBuilder ConfigureHostOptions(this Microsoft.Extensions.Hosting.IHostBuilder hostBuilder, System.Action<Microsoft.Extensions.Hosting.HostBuilderContext, Microsoft.Extensions.Hosting.HostOptions> configureOptions) { throw null; }
         public static Microsoft.Extensions.Hosting.IHostBuilder ConfigureHostOptions(this Microsoft.Extensions.Hosting.IHostBuilder hostBuilder, System.Action<Microsoft.Extensions.Hosting.HostOptions> configureOptions) { throw null; }
         public static Microsoft.Extensions.Hosting.IHostBuilder ConfigureLogging(this Microsoft.Extensions.Hosting.IHostBuilder hostBuilder, System.Action<Microsoft.Extensions.Hosting.HostBuilderContext, Microsoft.Extensions.Logging.ILoggingBuilder> configureLogging) { throw null; }
@@ -102,8 +102,8 @@ public static partial class HostingHostBuilderExtensions
     public partial class HostOptions
     {
         public HostOptions() { }
-        public System.TimeSpan ShutdownTimeout { get { throw null; } set { } }
         public Microsoft.Extensions.Hosting.BackgroundServiceExceptionBehavior BackgroundServiceExceptionBehavior { get { throw null; } set { } }
+        public System.TimeSpan ShutdownTimeout { get { throw null; } set { } }
     }
 }
 namespace Microsoft.Extensions.Hosting.Internal
@@ -133,7 +133,7 @@ public void Dispose() { }
     public partial class HostingEnvironment : Microsoft.Extensions.Hosting.IHostEnvironment, Microsoft.Extensions.Hosting.IHostingEnvironment
     {
         public HostingEnvironment() { }
-        public string ApplicationName { get { throw null; } set { } }
+        public string? ApplicationName { get { throw null; } set { } }
         public Microsoft.Extensions.FileProviders.IFileProvider ContentRootFileProvider { get { throw null; } set { } }
         public string ContentRootPath { get { throw null; } set { } }
         public string EnvironmentName { get { throw null; } set { } }

src/libraries/Microsoft.Extensions.Hosting/ref/Microsoft.Extensions.Hosting.csproj

@@ -1,6 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <TargetFrameworks>$(NetCoreAppCurrent);$(NetCoreAppMinimum);netstandard2.1;netstandard2.0;$(NetFrameworkMinimum)</TargetFrameworks>
+    <Nullable>enable</Nullable>
     <NoWarn>$(NoWarn);CS0618</NoWarn>
   </PropertyGroup>
 

src/libraries/Microsoft.Extensions.Hosting/src/Host.cs

@@ -50,13 +50,12 @@ public static IHostBuilder CreateDefaultBuilder() =>
         /// </remarks>
         /// <param name="args">The command line args.</param>
         /// <returns>The initialized <see cref="IHostBuilder"/>.</returns>
-        public static IHostBuilder CreateDefaultBuilder(string[] args)
+        public static IHostBuilder CreateDefaultBuilder(string[]? args)
         {
             HostBuilder builder = new();
             return builder.ConfigureDefaults(args);
         }
 
-#nullable enable
         /// <summary>
         /// Initializes a new instance of the <see cref="HostApplicationBuilder"/> class with pre-configured defaults.
         /// </summary>
@@ -95,6 +94,5 @@ public static IHostBuilder CreateDefaultBuilder(string[] args)
         /// </remarks>
         /// <param name="args">The command line args.</param>
         public static HostApplicationBuilder CreateApplicationBuilder(string[]? args) => new HostApplicationBuilder(args);
-#nullable disable
     }
 }

src/libraries/Microsoft.Extensions.Hosting/src/HostApplicationBuilder.cs

@@ -1,8 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-#nullable enable
-
 using System;
 using System.Collections;
 using System.Collections.Generic;
@@ -130,7 +128,7 @@ public HostApplicationBuilder(HostApplicationBuilderSettings? settings)
                 hostingEnvironment,
                 physicalFileProvider,
                 Configuration,
-                () => _appServices);
+                () => _appServices!);
 
             Logging = new LoggingBuilder(Services);
 

src/libraries/Microsoft.Extensions.Hosting/src/HostApplicationBuilderSettings.cs

@@ -1,8 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-#nullable enable
-
 using System.IO;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.Logging;

src/libraries/Microsoft.Extensions.Hosting/src/HostBuilder.cs

@@ -31,12 +31,12 @@ public partial class HostBuilder : IHostBuilder
         private List<IConfigureContainerAdapter> _configureContainerActions = new List<IConfigureContainerAdapter>();
         private IServiceFactoryAdapter _serviceProviderFactory = new ServiceFactoryAdapter<IServiceCollection>(new DefaultServiceProviderFactory());
         private bool _hostBuilt;
-        private IConfiguration _hostConfiguration;
-        private IConfiguration _appConfiguration;
-        private HostBuilderContext _hostBuilderContext;
-        private HostingEnvironment _hostingEnvironment;
-        private IServiceProvider _appServices;
-        private PhysicalFileProvider _defaultProvider;
+        private IConfiguration? _hostConfiguration;
+        private IConfiguration? _appConfiguration;
+        private HostBuilderContext? _hostBuilderContext;
+        private HostingEnvironment? _hostingEnvironment;
+        private IServiceProvider? _appServices;
+        private PhysicalFileProvider? _defaultProvider;
 
         /// <summary>
         /// A central location for sharing state between components during the host building process.
@@ -88,7 +88,7 @@ public IHostBuilder ConfigureServices(Action<HostBuilderContext, IServiceCollect
         /// <typeparam name="TContainerBuilder">The type of the builder to create.</typeparam>
         /// <param name="factory">A factory used for creating service providers.</param>
         /// <returns>The same instance of the <see cref="IHostBuilder"/> for chaining.</returns>
-        public IHostBuilder UseServiceProviderFactory<TContainerBuilder>(IServiceProviderFactory<TContainerBuilder> factory!!)
+        public IHostBuilder UseServiceProviderFactory<TContainerBuilder>(IServiceProviderFactory<TContainerBuilder> factory!!) where TContainerBuilder : notnull
         {
             _serviceProviderFactory = new ServiceFactoryAdapter<TContainerBuilder>(factory);
             return this;
@@ -100,9 +100,9 @@ public IHostBuilder UseServiceProviderFactory<TContainerBuilder>(IServiceProvide
         /// <param name="factory">A factory used for creating service providers.</param>
         /// <typeparam name="TContainerBuilder">The type of the builder to create.</typeparam>
         /// <returns>The same instance of the <see cref="IHostBuilder"/> for chaining.</returns>
-        public IHostBuilder UseServiceProviderFactory<TContainerBuilder>(Func<HostBuilderContext, IServiceProviderFactory<TContainerBuilder>> factory!!)
+        public IHostBuilder UseServiceProviderFactory<TContainerBuilder>(Func<HostBuilderContext, IServiceProviderFactory<TContainerBuilder>> factory!!) where TContainerBuilder : notnull
         {
-            _serviceProviderFactory = new ServiceFactoryAdapter<TContainerBuilder>(() => _hostBuilderContext, factory);
+            _serviceProviderFactory = new ServiceFactoryAdapter<TContainerBuilder>(() => _hostBuilderContext!, factory);
             return this;
         }
 
@@ -180,6 +180,7 @@ private static void Write<T>(
             diagnosticSource.Write(name, value);
         }
 
+        [MemberNotNull(nameof(_hostConfiguration))]
         private void InitializeHostConfiguration()
         {
             IConfigurationBuilder configBuilder = new ConfigurationBuilder()
@@ -192,9 +193,11 @@ private void InitializeHostConfiguration()
             _hostConfiguration = configBuilder.Build();
         }
 
+        [MemberNotNull(nameof(_defaultProvider))]
+        [MemberNotNull(nameof(_hostingEnvironment))]
         private void InitializeHostingEnvironment()
         {
-            (_hostingEnvironment, _defaultProvider) = CreateHostingEnvironment(_hostConfiguration);
+            (_hostingEnvironment, _defaultProvider) = CreateHostingEnvironment(_hostConfiguration!); // TODO-NULLABLE: https://github.com/dotnet/csharplang/discussions/5778. The same pattern exists below as well.
         }
 
         internal static (HostingEnvironment, PhysicalFileProvider) CreateHostingEnvironment(IConfiguration hostConfiguration)
@@ -218,7 +221,7 @@ internal static (HostingEnvironment, PhysicalFileProvider) CreateHostingEnvironm
             return (hostingEnvironment, physicalFileProvider);
         }
 
-        internal static string ResolveContentRootPath(string contentRootPath, string basePath)
+        internal static string ResolveContentRootPath(string? contentRootPath, string basePath)
         {
             if (string.IsNullOrEmpty(contentRootPath))
             {
@@ -231,29 +234,32 @@ internal static string ResolveContentRootPath(string contentRootPath, string bas
             return Path.Combine(Path.GetFullPath(basePath), contentRootPath);
         }
 
+        [MemberNotNull(nameof(_hostBuilderContext))]
         private void InitializeHostBuilderContext()
         {
             _hostBuilderContext = new HostBuilderContext(Properties)
             {
-                HostingEnvironment = _hostingEnvironment,
-                Configuration = _hostConfiguration
+                HostingEnvironment = _hostingEnvironment!,
+                Configuration = _hostConfiguration!
             };
         }
 
+        [MemberNotNull(nameof(_appConfiguration))]
         private void InitializeAppConfiguration()
         {
             IConfigurationBuilder configBuilder = new ConfigurationBuilder()
-                .SetBasePath(_hostingEnvironment.ContentRootPath)
-                .AddConfiguration(_hostConfiguration, shouldDisposeConfiguration: true);
+                .SetBasePath(_hostingEnvironment!.ContentRootPath)
+                .AddConfiguration(_hostConfiguration!, shouldDisposeConfiguration: true);
 
             foreach (Action<HostBuilderContext, IConfigurationBuilder> buildAction in _configureAppConfigActions)
             {
-                buildAction(_hostBuilderContext, configBuilder);
+                buildAction(_hostBuilderContext!, configBuilder);
             }
             _appConfiguration = configBuilder.Build();
-            _hostBuilderContext.Configuration = _appConfiguration;
+            _hostBuilderContext!.Configuration = _appConfiguration;
         }
 
+        [MemberNotNull(nameof(_appServices))]
         internal static void PopulateServiceCollection(
             IServiceCollection services,
             HostBuilderContext hostBuilderContext,
@@ -270,7 +276,7 @@ internal static void PopulateServiceCollection(
             // register configuration as factory to make it dispose with the service provider
             services.AddSingleton(_ => appConfiguration);
 #pragma warning disable CS0618 // Type or member is obsolete
-            services.AddSingleton(s => (IApplicationLifetime)s.GetService<IHostApplicationLifetime>());
+            services.AddSingleton(s => (IApplicationLifetime)s.GetRequiredService<IHostApplicationLifetime>());
 #pragma warning restore CS0618 // Type or member is obsolete
             services.AddSingleton<IHostApplicationLifetime, ApplicationLifetime>();
 
@@ -294,28 +300,29 @@ internal static void PopulateServiceCollection(
             services.AddLogging();
         }
 
+        [MemberNotNull(nameof(_appServices))]
         private void InitializeServiceProvider()
         {
             var services = new ServiceCollection();
 
             PopulateServiceCollection(
                 services,
-                _hostBuilderContext,
-                _hostingEnvironment,
-                _defaultProvider,
-                _appConfiguration,
-                () => _appServices);
+                _hostBuilderContext!,
+                _hostingEnvironment!,
+                _defaultProvider!,
+                _appConfiguration!,
+                () => _appServices!);
 
             foreach (Action<HostBuilderContext, IServiceCollection> configureServicesAction in _configureServicesActions)
             {
-                configureServicesAction(_hostBuilderContext, services);
+                configureServicesAction(_hostBuilderContext!, services);
             }
 
             object containerBuilder = _serviceProviderFactory.CreateBuilder(services);
 
             foreach (IConfigureContainerAdapter containerAction in _configureContainerActions)
             {
-                containerAction.ConfigureContainer(_hostBuilderContext, containerBuilder);
+                containerAction.ConfigureContainer(_hostBuilderContext!, containerBuilder);
             }
 
             _appServices = _serviceProviderFactory.CreateServiceProvider(containerBuilder);