Apply ArgumentNullException.ThrowIfNull to NLog source-code (#889)

Co-authored-by: Burak Akgerman <[email protected]>

src/NLog.Web.AspNetCore/AspNetExtensions.cs

@@ -14,6 +14,7 @@
 using Microsoft.Extensions.DependencyInjection.Extensions;
 using Microsoft.Extensions.Logging;
 using NLog.Extensions.Logging;
+using NLog.Internal;
 
 namespace NLog.Web
 {
@@ -286,10 +287,7 @@ public static IWebHostBuilder UseNLog(this IWebHostBuilder builder)
         /// <param name="options">Options for registration of the NLog LoggingProvider and enabling features.</param>
         public static IWebHostBuilder UseNLog(this IWebHostBuilder builder, NLogAspNetCoreOptions options)
         {
-            if (builder == null)
-            {
-                throw new ArgumentNullException(nameof(builder));
-            }
+            Guard.ThrowIfNull(builder);
 
             builder.ConfigureServices((builderContext, services) => AddNLogLoggerProvider(services, builderContext.Configuration, builderContext.HostingEnvironment as IHostEnvironment, options, CreateNLogLoggerProvider));
             return builder;
@@ -310,10 +308,7 @@ public static IHostBuilder UseNLog(this IHostBuilder builder)
         /// <param name="options">Options for registration of the NLog LoggingProvider and enabling features.</param>
         public static IHostBuilder UseNLog(this IHostBuilder builder, NLogAspNetCoreOptions options)
         {
-            if (builder == null)
-            {
-                throw new ArgumentNullException(nameof(builder));
-            }
+            Guard.ThrowIfNull(builder);
 
 #if ASP_NET_CORE2
             builder.ConfigureServices((builderContext, services) => AddNLogLoggerProvider(services, builderContext.Configuration, null, options, CreateNLogLoggerProvider));

src/NLog.Web.AspNetCore/Internal/Guard.cs

@@ -0,0 +1,69 @@
+//
+// Copyright (c) 2004-2021 Jaroslaw Kowalski <[email protected]>, Kim Christensen, Julian Verdurmen
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions
+// are met:
+//
+// * Redistributions of source code must retain the above copyright notice,
+//   this list of conditions and the following disclaimer.
+//
+// * Redistributions in binary form must reproduce the above copyright notice,
+//   this list of conditions and the following disclaimer in the documentation
+//   and/or other materials provided with the distribution.
+//
+// * Neither the name of Jaroslaw Kowalski nor the names of its
+//   contributors may be used to endorse or promote products derived from this
+//   software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+// THE POSSIBILITY OF SUCH DAMAGE.
+//
+
+#if !NETCOREAPP3_1_OR_GREATER
+namespace System.Runtime.CompilerServices
+{
+    [AttributeUsage(AttributeTargets.Parameter)]
+    sealed class CallerArgumentExpressionAttribute : Attribute
+    {
+        public CallerArgumentExpressionAttribute(string param)
+        {
+            Param = param;
+        }
+
+        public string Param { get; }
+    }
+}
+#endif
+
+namespace NLog.Internal
+{
+    using System;
+    using System.Runtime.CompilerServices;
+    internal static class Guard
+    {
+        internal static T ThrowIfNull<T>(
+            T arg,
+            [CallerArgumentExpression("arg")] string param = "")
+            where T : class
+        {
+            if (arg is null)
+            {
+                throw new ArgumentNullException(param);
+            }
+
+            return arg;
+        }
+    }
+}

tests/NLog.Web.AspNetCore.Tests/AspNetCoreTests.cs

@@ -248,6 +248,24 @@ public void UseNLog_LoadConfigurationFromSection()
             Assert.Equal("logger1|error1|Memory", logged[0]);
         }
 
+        [Fact]
+        public void UseNLogWithNullWebHostBuilderThrowsArgumentNullException()
+        {
+            IWebHostBuilder builder = null;
+            Assert.Throws<ArgumentNullException>(() => builder.UseNLog());
+
+            try
+            {
+                builder.UseNLog();
+            }
+            catch (Exception e)
+            {
+                Assert.IsType<ArgumentNullException>(e);
+
+                Assert.Equal("builder", (e as ArgumentNullException).ParamName);
+            }
+        }
+
         [Fact]
         public void UseNLog_ReplaceLoggerFactory_FromConfiguration()
         {

tests/NLog.Web.AspNetCore.Tests/CallerArgumentExpressionTests.cs

@@ -0,0 +1,27 @@
+using System.Runtime.CompilerServices;
+using Xunit;
+
+namespace NLog.Web.Tests
+{
+#if !NETCOREAPP3_1_OR_GREATER
+    public class CallerArgumentExpressionTests : TestBase
+    {
+        [Fact]
+        public void ReturnsNonNullInput()
+        {
+            var attr = new CallerArgumentExpressionAttribute("testInput");
+
+            Assert.Equal("testInput",attr.Param);
+        }
+
+        [Fact]
+        public void ReturnsNullInput()
+        {
+            var attr = new CallerArgumentExpressionAttribute(null);
+
+            Assert.Null(attr.Param);
+        }
+
+    }
+#endif
+}