Annotate Microsoft.AspNetCore.Routing for trimming

eng/TrimmableProjects.props

@@ -19,6 +19,7 @@
     <TrimmableProject Include="Microsoft.AspNetCore.Http" />
     <TrimmableProject Include="Microsoft.AspNetCore.Metadata" />
     <TrimmableProject Include="Microsoft.AspNetCore.Routing.Abstractions" />
+    <TrimmableProject Include="Microsoft.AspNetCore.Routing" />
     <TrimmableProject Include="Microsoft.AspNetCore.WebUtilities" />
     <TrimmableProject Include="Microsoft.AspNetCore.Connections.Abstractions" />
     <TrimmableProject Include="Microsoft.AspNetCore.Server.HttpSys" />

src/Http/Http/src/Microsoft.AspNetCore.Http.csproj

@@ -8,7 +8,6 @@
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageTags>aspnetcore</PackageTags>
     <IsPackable>false</IsPackable>
-    <Nullable>enable</Nullable>
     <IsTrimmable>true</IsTrimmable>
   </PropertyGroup>
 

src/Http/Routing/src/Builder/EndpointRouteBuilderExtensions.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Reflection;
 using System.Runtime.CompilerServices;
@@ -18,6 +19,8 @@ namespace Microsoft.AspNetCore.Builder;
 /// </summary>
 public static class EndpointRouteBuilderExtensions
 {
+    internal const string MapEndpointTrimmerWarning = "This API may perform reflection on the supplied delegate and its parameters. These types may be trimmed if not directly referenced.";
+
     // Avoid creating a new array every call
     private static readonly string[] GetVerb = new[] { HttpMethods.Get };
     private static readonly string[] PostVerb = new[] { HttpMethods.Post };
@@ -33,6 +36,7 @@ public static class EndpointRouteBuilderExtensions
     /// <param name="pattern">The route pattern.</param>
     /// <param name="requestDelegate">The delegate executed when the endpoint is matched.</param>
     /// <returns>A <see cref="IEndpointConventionBuilder"/> that can be used to further customize the endpoint.</returns>
+    [RequiresUnreferencedCode(EndpointRouteBuilderExtensions.MapEndpointTrimmerWarning)]
     public static IEndpointConventionBuilder MapGet(
         this IEndpointRouteBuilder endpoints,
         string pattern,
@@ -220,6 +224,7 @@ public static IEndpointConventionBuilder Map(
     /// <param name="pattern">The route pattern.</param>
     /// <param name="handler">The delegate executed when the endpoint is matched.</param>
     /// <returns>A <see cref="RouteHandlerBuilder"/> that can be used to further customize the endpoint.</returns>
+    [RequiresUnreferencedCode(MapEndpointTrimmerWarning)]
     public static RouteHandlerBuilder MapGet(
         this IEndpointRouteBuilder endpoints,
         string pattern,
@@ -236,6 +241,7 @@ public static RouteHandlerBuilder MapGet(
     /// <param name="pattern">The route pattern.</param>
     /// <param name="handler">The delegate executed when the endpoint is matched.</param>
     /// <returns>A <see cref="RouteHandlerBuilder"/> that can be used to further customize the endpoint.</returns>
+    [RequiresUnreferencedCode(MapEndpointTrimmerWarning)]
     public static RouteHandlerBuilder MapPost(
         this IEndpointRouteBuilder endpoints,
         string pattern,
@@ -252,6 +258,7 @@ public static RouteHandlerBuilder MapPost(
     /// <param name="pattern">The route pattern.</param>
     /// <param name="handler">The delegate executed when the endpoint is matched.</param>
     /// <returns>A <see cref="RouteHandlerBuilder"/> that can be used to further customize the endpoint.</returns>
+    [RequiresUnreferencedCode(MapEndpointTrimmerWarning)]
     public static RouteHandlerBuilder MapPut(
         this IEndpointRouteBuilder endpoints,
         string pattern,
@@ -268,6 +275,7 @@ public static RouteHandlerBuilder MapPut(
     /// <param name="pattern">The route pattern.</param>
     /// <param name="handler">The delegate executed when the endpoint is matched.</param>
     /// <returns>A <see cref="RouteHandlerBuilder"/> that can be used to further customize the endpoint.</returns>
+    [RequiresUnreferencedCode(MapEndpointTrimmerWarning)]
     public static RouteHandlerBuilder MapDelete(
         this IEndpointRouteBuilder endpoints,
         string pattern,
@@ -284,6 +292,7 @@ public static RouteHandlerBuilder MapDelete(
     /// <param name="pattern">The route pattern.</param>
     /// <param name="handler">The <see cref="Delegate" /> executed when the endpoint is matched.</param>
     /// <returns>A <see cref="RouteHandlerBuilder"/> that can be used to further customize the endpoint.</returns>
+    [RequiresUnreferencedCode(MapEndpointTrimmerWarning)]
     public static RouteHandlerBuilder MapPatch(
         this IEndpointRouteBuilder endpoints,
         string pattern,
@@ -301,6 +310,7 @@ public static RouteHandlerBuilder MapPatch(
     /// <param name="handler">The delegate executed when the endpoint is matched.</param>
     /// <param name="httpMethods">HTTP methods that the endpoint will match.</param>
     /// <returns>A <see cref="RouteHandlerBuilder"/> that can be used to further customize the endpoint.</returns>
+    [RequiresUnreferencedCode(MapEndpointTrimmerWarning)]
     public static RouteHandlerBuilder MapMethods(
        this IEndpointRouteBuilder endpoints,
        string pattern,
@@ -348,6 +358,7 @@ static bool ShouldDisableInferredBody(string method)
     /// <param name="pattern">The route pattern.</param>
     /// <param name="handler">The delegate executed when the endpoint is matched.</param>
     /// <returns>A <see cref="RouteHandlerBuilder"/> that can be used to further customize the endpoint.</returns>
+    [RequiresUnreferencedCode(MapEndpointTrimmerWarning)]
     public static RouteHandlerBuilder Map(
         this IEndpointRouteBuilder endpoints,
         string pattern,
@@ -364,6 +375,7 @@ public static RouteHandlerBuilder Map(
     /// <param name="pattern">The route pattern.</param>
     /// <param name="handler">The delegate executed when the endpoint is matched.</param>
     /// <returns>A <see cref="RouteHandlerBuilder"/> that can be used to further customize the endpoint.</returns>
+    [RequiresUnreferencedCode(MapEndpointTrimmerWarning)]
     public static RouteHandlerBuilder Map(
         this IEndpointRouteBuilder endpoints,
         RoutePattern pattern,
@@ -391,6 +403,7 @@ public static RouteHandlerBuilder Map(
     /// <c>{*path:nonfile}</c>. The order of the registered endpoint will be <c>int.MaxValue</c>.
     /// </para>
     /// </remarks>
+    [RequiresUnreferencedCode(MapEndpointTrimmerWarning)]
     public static RouteHandlerBuilder MapFallback(this IEndpointRouteBuilder endpoints, Delegate handler)
     {
         if (endpoints == null)
@@ -427,6 +440,7 @@ public static RouteHandlerBuilder MapFallback(this IEndpointRouteBuilder endpoin
     /// to exclude requests for static files.
     /// </para>
     /// </remarks>
+    [RequiresUnreferencedCode(MapEndpointTrimmerWarning)]
     public static RouteHandlerBuilder MapFallback(
         this IEndpointRouteBuilder endpoints,
         string pattern,
@@ -453,6 +467,7 @@ public static RouteHandlerBuilder MapFallback(
         return conventionBuilder;
     }
 
+    [RequiresUnreferencedCode(MapEndpointTrimmerWarning)]
     private static RouteHandlerBuilder Map(
         this IEndpointRouteBuilder endpoints,
         RoutePattern pattern,
@@ -515,7 +530,11 @@ private static RouteHandlerBuilder Map(
         }
 
         var routeHandlerBuilder = new RouteHandlerBuilder(dataSource.AddEndpointBuilder(builder));
-        routeHandlerBuilder.Add(endpointBuilder =>
+        routeHandlerBuilder.Add(RouteHandlerBuilderConvention);
+
+        [UnconditionalSuppressMessage("Trimmer", "IL2026", Justification = "We surface a RequireUnreferencedCode in the call to enclosing Map method. " +
+            "The trimmer is unable to infer this on the nested lambda.")]
+        void RouteHandlerBuilderConvention(EndpointBuilder endpointBuilder)
         {
             var options = new RequestDelegateFactoryOptions
             {
@@ -545,7 +564,7 @@ private static RouteHandlerBuilder Map(
                 }
             }
             endpointBuilder.RequestDelegate = filteredRequestDelegateResult.RequestDelegate;
-        });
+        }
 
         return routeHandlerBuilder;
     }

src/Http/Routing/src/DefaultInlineConstraintResolver.cs

@@ -34,7 +34,7 @@ public DefaultInlineConstraintResolver(IOptions<RouteOptions> routeOptions, ISer
             throw new ArgumentNullException(nameof(serviceProvider));
         }
 
-        _inlineConstraintMap = routeOptions.Value.ConstraintMap;
+        _inlineConstraintMap = routeOptions.Value.TrimmerSafeConstraintMap;
         _serviceProvider = serviceProvider;
     }
 

src/Http/Routing/src/DefaultParameterPolicyFactory.cs

@@ -43,17 +43,17 @@ public override IParameterPolicy Create(RoutePatternParameterPart? parameter, st
         }
 
         var parameterPolicy = ParameterPolicyActivator.ResolveParameterPolicy<IParameterPolicy>(
-            _options.ConstraintMap,
+            _options.TrimmerSafeConstraintMap,
             _serviceProvider,
             inlineText,
             out var parameterPolicyKey);
 
         if (parameterPolicy == null)
         {
             throw new InvalidOperationException(Resources.FormatRoutePattern_ConstraintReferenceNotFound(
-                    parameterPolicyKey,
-                    typeof(RouteOptions),
-                    nameof(RouteOptions.ConstraintMap)));
+                parameterPolicyKey,
+                typeof(RouteOptions),
+                nameof(RouteOptions.ConstraintMap)));
         }
 
         if (parameterPolicy is IRouteConstraint constraint)

src/Http/Routing/src/EndpointRoutingMiddleware.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Routing.Matching;
@@ -96,14 +97,21 @@ private Task SetRoutingAndContinue(HttpContext httpContext)
             // Raise an event if the route matched
             if (_diagnosticListener.IsEnabled() && _diagnosticListener.IsEnabled(DiagnosticsEndpointMatchedKey))
             {
-                // We're just going to send the HttpContext since it has all of the relevant information
-                _diagnosticListener.Write(DiagnosticsEndpointMatchedKey, httpContext);
+                Write(_diagnosticListener, httpContext);
             }
 
             Log.MatchSuccess(_logger, endpoint);
         }
 
         return _next(httpContext);
+
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:UnrecognizedReflectionPattern",
+            Justification = "The values being passed into Write are being consumed by the application already.")]
+        static void Write(DiagnosticListener diagnosticListener, HttpContext httpContext)
+        {
+            // We're just going to send the HttpContext since it has all of the relevant information
+            diagnosticListener.Write(DiagnosticsEndpointMatchedKey, httpContext);
+        }
     }
 
     // Initialization is async to avoid blocking threads while reflection and things