feat: annotate trim/AOT requirements ([RequiresUnreferencedCode]/[RequiresDynamicCode]) (#6)

Honest trim/AOT signal rather than a source-gen rewrite: the real blocker is
Scrutor's runtime assembly scan (fundamentally not trim/AOT-safe), so removing our
own reflection would gain nothing while staying a Scrutor extension. Instead, the
public AsHttpClient entry points now carry [RequiresUnreferencedCode] +
[RequiresDynamicCode] (net8.0+), so consumers building trimmed/AOT get accurate
warnings at the call site instead of silent breakage.

- Enable EnableTrimAnalyzer + EnableAotAnalyzer on the net8.0 target to self-validate
  the annotations. Only IL3050 (MakeGenericMethod) surfaced; suppressed at that site
  with [UnconditionalSuppressMessage] + justification (the override can't carry
  Requires*; the public entry points already warn callers).
- Attributes/usings guarded by NET8_0_OR_GREATER (the attrs + analyzers don't exist
  on netstandard2.0, where trimming/AOT isn't a concern).
- Public API baseline updated to include the new attributes.

Build clean (0 warnings both TFMs); all 7 specs pass.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: ChrisonSimtian

Scrutor.Extensions.HttpClient/Extensions/HttpClientExtensions.cs

@@ -1,6 +1,9 @@
 using System;
 using System.Linq;
 using System.Reflection;
+#if NET8_0_OR_GREATER
+using System.Diagnostics.CodeAnalysis;
+#endif
 using Scrutor;
 
 namespace Microsoft.Extensions.DependencyInjection;
@@ -14,12 +17,24 @@ namespace Microsoft.Extensions.DependencyInjection;
 /// See https://github.com/khellang/Scrutor/issues/180.</remarks>
 public static class HttpClientExtensions
 {
+    // Honest trim/AOT signal: registration runs Scrutor's runtime assembly scan and closes the
+    // generic AddHttpClient<TClient,TImplementation> over the scanned types via reflection. Consumers
+    // building trimmed/AOT get a warning at these entry points instead of silent breakage.
+    private const string TrimMessage =
+        "Registers types discovered by Scrutor's runtime assembly scan as typed HttpClients; the scanned client types may be removed by the trimmer.";
+    private const string AotMessage =
+        "Closes the generic AddHttpClient<TClient,TImplementation> over the scanned types via MakeGenericMethod, which requires runtime code generation.";
+
     /// <summary>
     /// Registers each scanned service as a typed <see cref="System.Net.Http.HttpClient"/> bound to
     /// the named client <paramref name="name"/> (so they share that client's configuration).
     /// </summary>
     /// <param name="selector">The Scrutor service-type selector.</param>
     /// <param name="name">The name of a client registered via <c>AddHttpClient(name, ...)</c>.</param>
+#if NET8_0_OR_GREATER
+    [RequiresUnreferencedCode(TrimMessage)]
+    [RequiresDynamicCode(AotMessage)]
+#endif
     public static IServiceTypeSelector AsHttpClient(this IServiceTypeSelector selector, string name = "")
         => selector.UsingRegistrationStrategy(new HttpClientRegistrationStrategy(name));
 
@@ -28,6 +43,10 @@ public static IServiceTypeSelector AsHttpClient(this IServiceTypeSelector select
     /// its own default client named after the service type.
     /// </summary>
     /// <param name="selector">The Scrutor service-type selector.</param>
+#if NET8_0_OR_GREATER
+    [RequiresUnreferencedCode(TrimMessage)]
+    [RequiresDynamicCode(AotMessage)]
+#endif
     public static IServiceTypeSelector AsHttpClient(this IServiceTypeSelector selector)
         => selector.UsingRegistrationStrategy(new HttpClientRegistrationStrategy(name: null));
 
@@ -44,6 +63,13 @@ private sealed class HttpClientRegistrationStrategy(string? name) : Registration
         private static readonly MethodInfo NamedAddHttpClient = ResolveAddHttpClient(named: true);
         private static readonly MethodInfo UnnamedAddHttpClient = ResolveAddHttpClient(named: false);
 
+        // Apply overrides Scrutor's (un-annotated) RegistrationStrategy.Apply, so the RequiresDynamicCode
+        // warning can't propagate here. It's already surfaced to consumers on the public AsHttpClient
+        // entry points (the only way to reach this strategy), so suppress the internal MakeGenericMethod site.
+#if NET8_0_OR_GREATER
+        [UnconditionalSuppressMessage("AOT", "IL3050",
+            Justification = "AsHttpClient() entry points are marked [RequiresDynamicCode]; callers are warned. AddHttpClient<,> has no non-generic overload.")]
+#endif
         public override void Apply(IServiceCollection services, ServiceDescriptor descriptor)
         {
             var serviceType = descriptor.ServiceType;

Scrutor.Extensions.HttpClient/Scrutor.Extensions.HttpClient.csproj

@@ -10,6 +10,14 @@
 		<LangVersion>latest</LangVersion>
 	</PropertyGroup>
 
+	<!-- Turn on the trim + AOT analyzers on the modern target so our own build validates the
+	     [RequiresUnreferencedCode]/[RequiresDynamicCode] annotations are well-formed and the
+	     intentional reflection is properly justified. (netstandard2.0 has no such analyzers.) -->
+	<PropertyGroup Condition="'$(TargetFramework)' == 'net8.0'">
+		<EnableTrimAnalyzer>true</EnableTrimAnalyzer>
+		<EnableAotAnalyzer>true</EnableAotAnalyzer>
+	</PropertyGroup>
+
 	<PropertyGroup Label="Package">
 		<Title>Scrutor HttpClient Extension</Title>
 		<Authors>Chrison Simtian</Authors>

tests/Scrutor.Extensions.HttpClient.Specs/PublicApiSpecs.Public_api_surface_has_not_changed.verified.txt

@@ -5,7 +5,15 @@ namespace Microsoft.Extensions.DependencyInjection
 {
     public static class HttpClientExtensions
     {
+        [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Closes the generic AddHttpClient<TClient,TImplementation> over the scanned types " +
+            "via MakeGenericMethod, which requires runtime code generation.")]
+        [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Registers types discovered by Scrutor\'s runtime assembly scan as typed HttpClient" +
+            "s; the scanned client types may be removed by the trimmer.")]
         public static Scrutor.IServiceTypeSelector AsHttpClient(this Scrutor.IServiceTypeSelector selector) { }
+        [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Closes the generic AddHttpClient<TClient,TImplementation> over the scanned types " +
+            "via MakeGenericMethod, which requires runtime code generation.")]
+        [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Registers types discovered by Scrutor\'s runtime assembly scan as typed HttpClient" +
+            "s; the scanned client types may be removed by the trimmer.")]
         public static Scrutor.IServiceTypeSelector AsHttpClient(this Scrutor.IServiceTypeSelector selector, string name = "") { }
     }
 }