We're bumping the major version; mark IWebHostBuilder extension methods as obsolete, so that we can eventually drop this from the package (IHostBuilder is the modern replacement).

Author: nblumhardt

src/Serilog.AspNetCore/Serilog.AspNetCore.csproj

@@ -24,6 +24,10 @@
     <None Include="..\..\assets\icon.png" Pack="true" Visible="false" PackagePath="" />
   </ItemGroup>
 
+  <PropertyGroup Condition="'$(TargetFramework)' != 'netstandard2.0' and '$(TargetFramework)' != 'netstandard2.1'">
+    <DefineConstants>$(DefineConstants);HOSTBUILDER</DefineConstants>
+  </PropertyGroup>
+  
   <ItemGroup>
     <PackageReference Include="Serilog" Version="2.10.0" />
     <PackageReference Include="Serilog.Extensions.Hosting" Version="4.1.2" />

src/Serilog.AspNetCore/SerilogWebHostBuilderExtensions.cs

@@ -38,6 +38,9 @@ public static class SerilogWebHostBuilderExtensions
         /// <c>WriteTo.Providers()</c> configuration method, enabling other <see cref="ILoggerProvider"/>s to receive events. By
         /// default, only Serilog sinks will receive events.</param>
         /// <returns>The web host builder.</returns>
+#if HOSTBUILDER
+        [Obsolete("Prefer UseSerilog() on IHostBuilder")]
+#endif
         public static IWebHostBuilder UseSerilog(
             this IWebHostBuilder builder, 
             ILogger logger = null, 
@@ -83,6 +86,9 @@ public static IWebHostBuilder UseSerilog(
         /// the Microsoft.Extensions.Logging API. Normally, equivalent Serilog sinks are used in place of providers. Specify
         /// <c>true</c> to write events to all providers.</param>
         /// <returns>The web host builder.</returns>
+#if HOSTBUILDER
+        [Obsolete("Prefer UseSerilog() on IHostBuilder")]
+#endif
         public static IWebHostBuilder UseSerilog(
             this IWebHostBuilder builder,
             Action<WebHostBuilderContext, LoggerConfiguration> configureLogger,

test/Serilog.AspNetCore.Tests/SerilogWebHostBuilderExtensionsTests.cs

@@ -12,6 +12,9 @@
 using Serilog.Filters;
 using Serilog.AspNetCore.Tests.Support;
 
+// Newer frameworks provide IHostBuilder
+#pragma warning disable CS0618
+
 namespace Serilog.AspNetCore.Tests
 {
     public class SerilogWebHostBuilderExtensionsTests : IClassFixture<SerilogWebApplicationFactory>