Add support for IsEnhancedModelMetadataSupported feature switch (#42310)

Author: marcpopMSFT

src/WebSdk/ProjectSystem/Targets/Microsoft.NET.Sdk.Web.ProjectSystem.targets

@@ -60,6 +60,7 @@ Copyright (c) .NET Foundation. All rights reserved.
 
     <!-- Default feature switch values for trimmed apps. -->
     <SignalRCustomAwaitableSupport Condition="'$(SignalRCustomAwaitableSupport)' == ''">false</SignalRCustomAwaitableSupport>
+    <MvcEnhancedModelMetadataSupport Condition="'$(MvcEnhancedModelMetadataSupport)' == ''">false</MvcEnhancedModelMetadataSupport>
   </PropertyGroup>
 
   <PropertyGroup>

src/WebSdk/Web/Targets/Sdk.Server.targets

@@ -44,6 +44,10 @@ Copyright (c) .NET Foundation. All rights reserved.
                                     Condition="'$(SignalRCustomAwaitableSupport)' != ''"
                                     Value="$(SignalRCustomAwaitableSupport)"
                                     Trim="true" />
+    <RuntimeHostConfigurationOption Include="Microsoft.AspNetCore.Mvc.ApiExplorer.IsEnhancedModelMetadataSupported"
+                                    Condition="'$(MvcEnhancedModelMetadataSupport)' != ''"
+                                    Value="$(MvcEnhancedModelMetadataSupport)"
+                                    Trim="true" />
   </ItemGroup>
 
 </Project>

test/Microsoft.NET.Sdk.Web.Tests/PublishTests.cs

@@ -41,6 +41,8 @@ public void TrimmingOptions_Are_Defaulted_Correctly_On_Trimmed_Apps(string targe
 
             configProperties["Microsoft.AspNetCore.SignalR.Hub.IsCustomAwaitableSupported"].GetValue<bool>()
                     .Should().BeFalse();
+            configProperties["Microsoft.AspNetCore.Mvc.ApiExplorer.IsEnhancedModelMetadataSupported"].GetValue<bool>()
+                    .Should().BeFalse();
             configProperties["System.Text.Json.JsonSerializer.IsReflectionEnabledByDefault"].GetValue<bool>()
                     .Should().BeFalse();
         }
@@ -97,6 +99,7 @@ public void TrimmingOptions_Are_Defaulted_Correctly_On_Aot_Apps(string targetFra
             var responseFileContents = File.ReadLines(responseFile);
 
             responseFileContents.Should().Contain("--feature:Microsoft.AspNetCore.SignalR.Hub.IsCustomAwaitableSupported=false");
+            responseFileContents.Should().Contain("--feature:Microsoft.AspNetCore.Mvc.ApiExplorer.IsEnhancedModelMetadataSupported=false");
             responseFileContents.Should().Contain("--feature:System.Text.Json.JsonSerializer.IsReflectionEnabledByDefault=false");
             responseFileContents.Should().Contain("--feature:System.Diagnostics.Tracing.EventSource.IsSupported=true");
             responseFileContents.Should().Contain("--runtimeknob:System.GC.DynamicAdaptationMode=1");