Merged PR 21913: Merge from public release/6.0

# {PR title}

Summary of the changes (Less than 80 chars)

## Description

{Detail}

Fixes #{bug number} (in this specific format)

## Customer Impact

{Justification}

## Regression?

- [ ] Yes
- [ ] No

[If yes, specify the version the behavior has regressed from]

## Risk

- [ ] High
- [ ] Medium
- [ ] Low

[Justify the selection above]

## Verification

- [ ] Manual (required)
- [ ] Automated

## Packaging changes reviewed?

- [ ] Yes
- [ ] No
- [ ] N/A

----

## When servicing release/2.1

- [ ] Make necessary changes in eng/PatchConfig.props

src/Components/README.md

@@ -26,6 +26,7 @@ The following contains a description of each sub-directory in the `Components` d
   - `Server`: Contains the implementation for WASM-specific extension methods and the launch logic for the debugging proxy
   - `WebAssembly`: Contains WebAssembly-specific implementations of the renderer, HostBuilder, etc.
   - `WebAssembly.Authentication`: Contains the WASM-specific implementations
+- `WebView`: Contains the source files to support [Blazor Hybrid](https://github.com/dotnet/maui/tree/main/src/BlazorWebView) within [`dotnet/maui`](https://github.com/dotnet/maui). Changes in this project can be tested with `dotnet/maui` following [this guide](https://github.com/dotnet/maui/wiki/Blazor-Desktop#aspnet-core).
 
 ## Development Setup
 

src/Components/WebView/WebView/src/IpcSender.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Diagnostics.CodeAnalysis;
+using System.Runtime.ExceptionServices;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Components.RenderTree;
 using Microsoft.JSInterop;
@@ -62,8 +63,12 @@ public void SendByteArray(int id, byte[] data)
 
         public void NotifyUnhandledException(Exception exception)
         {
+            // Send the serialized exception to the WebView for display
             var message = IpcCommon.Serialize(IpcCommon.OutgoingMessageType.NotifyUnhandledException, exception.Message, exception.StackTrace);
             _dispatcher.InvokeAsync(() => _messageDispatcher(message));
+
+            // Also rethrow so the AppDomain's UnhandledException handler gets notified
+            _dispatcher.InvokeAsync(() => ExceptionDispatchInfo.Capture(exception).Throw());
         }
 
         private void DispatchMessageWithErrorHandling(string message)

src/Components/WebView/WebView/src/Services/WebViewRenderer.cs

@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Runtime.ExceptionServices;
 using System.Text.Json;
 using Microsoft.AspNetCore.Components.RenderTree;
 using Microsoft.AspNetCore.Components.Web;
@@ -38,9 +37,6 @@ protected override void HandleException(Exception exception)
         {
             // Notify the JS code so it can show the in-app UI
             _ipcSender.NotifyUnhandledException(exception);
-
-            // Also rethrow so the AppDomain's UnhandledException handler gets notified
-            ExceptionDispatchInfo.Capture(exception).Throw();
         }
 
         protected override Task UpdateDisplayAsync(in RenderBatch renderBatch)

src/Servers/HttpSys/src/Microsoft.AspNetCore.Server.HttpSys.csproj

@@ -18,6 +18,7 @@
     <Compile Include="$(SharedSourceRoot)HttpSys\**\*.cs" />
     <Compile Include="$(SharedSourceRoot)Buffers.MemoryPool\*.cs" LinkBase="MemoryPool" />
     <Compile Include="$(SharedSourceRoot)ServerInfrastructure\StringUtilities.cs" LinkBase="ServerInfrastructure\StringUtilities.cs" />
+    <Compile Include="$(SharedSourceRoot)ServerInfrastructure\HttpCharacters.cs" LinkBase="ServerInfrastructure\HttpCharacters.cs" />
     <Compile Include="$(SharedSourceRoot)TaskToApm.cs" />
   </ItemGroup>
 

src/Servers/HttpSys/test/FunctionalTests/ResponseHeaderTests.cs

@@ -113,6 +113,27 @@ public async Task ResponseHeaders_ServerSendsCustomHeaders_Success()
             }
         }
 
+        [ConditionalFact]
+        public async Task ResponseHeaders_ServerSendsNonAsciiHeaders_Success()
+        {
+            string address;
+            using (Utilities.CreateHttpServer(out address, httpContext =>
+            {
+                var responseInfo = httpContext.Features.Get<IHttpResponseFeature>();
+                var responseHeaders = responseInfo.Headers;
+                responseHeaders["Custom-Header1"] = new string[] { "Dašta" };
+                return Task.FromResult(0);
+            }))
+            {
+                var socketsHttpHandler = new SocketsHttpHandler() { ResponseHeaderEncodingSelector = (_, _) => Encoding.UTF8 };
+                var httpClient = new HttpClient(socketsHttpHandler);
+                var response = await httpClient.GetAsync(address);
+                response.EnsureSuccessStatusCode();
+                Assert.True(response.Headers.TryGetValues("Custom-Header1", out var header));
+                Assert.Equal("Dašta", header.Single());
+            }
+        }
+
         [ConditionalFact]
         public async Task ResponseHeaders_ServerSendsConnectionClose_Closed()
         {

src/Servers/Kestrel/Core/src/Internal/Http/Http1Connection.cs

@@ -8,6 +8,7 @@
 using System.IO.Pipelines;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Connections;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Features;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
 

src/Servers/Kestrel/Core/src/Internal/Http/HttpHeaders.cs

@@ -10,7 +10,6 @@
 using System.Runtime.InteropServices;
 using System.Text;
 using Microsoft.AspNetCore.Http;
-using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
 using Microsoft.Extensions.Primitives;
 using Microsoft.Net.Http.Headers;
 

src/Servers/Kestrel/Core/src/Internal/Http/HttpParser.cs

@@ -6,6 +6,7 @@
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http

src/Servers/Kestrel/Core/src/Internal/Http2/Http2Stream.cs

@@ -16,6 +16,7 @@
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
 using Microsoft.Extensions.Primitives;
 using Microsoft.Net.Http.Headers;
+using HttpCharacters = Microsoft.AspNetCore.Http.HttpCharacters;
 using HttpMethods = Microsoft.AspNetCore.Http.HttpMethods;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2

src/Servers/Kestrel/Core/src/Internal/Http3/Http3Stream.cs

@@ -15,6 +15,7 @@
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Primitives;
 using Microsoft.Net.Http.Headers;
+using HttpCharacters = Microsoft.AspNetCore.Http.HttpCharacters;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http3
 {

src/Servers/Kestrel/Core/src/Internal/KestrelServerImpl.cs

@@ -11,6 +11,7 @@
 using Microsoft.AspNetCore.Connections;
 using Microsoft.AspNetCore.Hosting.Server;
 using Microsoft.AspNetCore.Hosting.Server.Features;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Features;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;

src/Servers/Kestrel/Core/test/HttpResponseHeadersTests.cs

@@ -241,6 +241,18 @@ public void AddingNonAsciiCharactersWithCustomEncoderWorks(string value)
             ((IDictionary<string, StringValues>)responseHeaders).Add("Unknown", value);
         }
 
+        [Fact]
+        public void AddingTabCharactersToHeaderPropertyWorks()
+        {
+            var responseHeaders = (IHeaderDictionary)new HttpResponseHeaders();
+
+            // Known special header
+            responseHeaders.Allow = "Da\tta";
+
+            // Unknown header fallback
+            responseHeaders.Accept = "Da\tta";
+        }
+
         [Fact]
         public void ThrowsWhenAddingHeaderAfterReadOnlyIsSet()
         {

src/Shared/HttpSys/RequestProcessing/HeaderCollection.cs

@@ -272,12 +272,10 @@ public static void ValidateHeaderCharacters(string headerCharacters)
         {
             if (headerCharacters != null)
             {
-                foreach (var ch in headerCharacters)
+                var invalid = HttpCharacters.IndexOfInvalidFieldValueCharExtended(headerCharacters);
+                if (invalid >= 0)
                 {
-                    if (ch < 0x20)
-                    {
-                        throw new InvalidOperationException(string.Format(CultureInfo.CurrentCulture, "Invalid control character in header: 0x{0:X2}", (byte)ch));
-                    }
+                    throw new InvalidOperationException(string.Format(CultureInfo.CurrentCulture, "Invalid control character in header: 0x{0:X2}", headerCharacters[invalid]));
                 }
             }
         }

src/Servers/Kestrel/Core/src/Internal/Infrastructure/HttpCharacters.cs → src/Shared/ServerInfrastructure/HttpCharacters.cs

@@ -4,7 +4,7 @@
 using System;
 using System.Runtime.CompilerServices;
 
-namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure
+namespace Microsoft.AspNetCore.Http
 {
     internal static class HttpCharacters
     {
@@ -107,6 +107,9 @@ private static bool[] InitializeFieldValue()
         {
             // field-value https://tools.ietf.org/html/rfc7230#section-3.2
             var fieldValue = new bool[_tableSize];
+
+            fieldValue[0x9] = true; // HTAB
+
             for (var c = 0x20; c <= 0x7e; c++) // VCHAR and SP
             {
                 fieldValue[c] = true;
@@ -182,7 +185,8 @@ public static int IndexOfInvalidTokenChar(ReadOnlySpan<byte> span)
             return -1;
         }
 
-        // Disallows control characters and anything more than 0x7F
+        // Follows field-value rules in https://tools.ietf.org/html/rfc7230#section-3.2
+        // Disallows characters > 0x7E.
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static int IndexOfInvalidFieldValueChar(string s)
         {
@@ -200,7 +204,7 @@ public static int IndexOfInvalidFieldValueChar(string s)
             return -1;
         }
 
-        // Disallows control characters but allows extended characters > 0x7F
+        // Follows field-value rules for chars <= 0x7F. Allows extended characters > 0x7F.
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static int IndexOfInvalidFieldValueCharExtended(string s)
         {