Don't call into unsupported APIs on build targets which don't support quic

eng/versioning.targets

@@ -59,21 +59,28 @@
 
   <ItemGroup>
     <_unsupportedOSPlatforms Include="$(UnsupportedOSPlatforms)" />
+    <_supportedOSPlatforms Include="$(SupportedOSPlatforms)" />
   </ItemGroup>
 
-  <!-- Adds UnsupportedOSPlatform attribute to the assembly when:
-      * At least one <UnsupportedOSPlatforms /> has been specified
+  <!-- Adds UnsupportedOSPlatform and SupportedOSPlatform attributes to the assembly when:
+      * At least one <UnsupportedOSPlatforms /> or <SupportedOSPlatforms /> has been specified
       * This isn't a test project
       * This is a cross-platform target
       * The build isn't targeting .NET Framework
     -->
-  <Target Name="AddUnsupportedOSPlatformAttribute" BeforeTargets="GenerateAssemblyInfo" AfterTargets="PrepareForBuild"
-    Condition="'@(_unsupportedOSPlatforms)' != '' and '$(TargetsAnyOS)' == 'true' and '$(IsTestProject)' != 'true' and '$(TargetFrameworkIdentifier)' != '.NETFramework'">
-    <ItemGroup>
+  <Target Name="AddOSPlatformAttributes" BeforeTargets="GenerateAssemblyInfo" AfterTargets="PrepareForBuild"
+    Condition="'$(TargetsAnyOS)' == 'true' and '$(IsTestProject)' != 'true' and '$(TargetFrameworkIdentifier)' != '.NETFramework'">
+    <ItemGroup Condition="'@(_unsupportedOSPlatforms)' != ''">
       <AssemblyAttribute Include="System.Runtime.Versioning.UnsupportedOSPlatform">
         <_Parameter1>%(_unsupportedOSPlatforms.Identity)</_Parameter1>
       </AssemblyAttribute>
     </ItemGroup>
+
+    <ItemGroup Condition="'@(_supportedOSPlatforms)' != ''">
+      <AssemblyAttribute Include="System.Runtime.Versioning.SupportedOSPlatform">
+        <_Parameter1>%(_supportedOSPlatforms.Identity)</_Parameter1>
+      </AssemblyAttribute>
+    </ItemGroup>
   </Target>
 
   <PropertyGroup>

src/libraries/System.Net.Http/src/System.Net.Http.csproj

@@ -19,7 +19,6 @@
   <ItemGroup>
     <ILLinkSubstitutionsXmls Include="$(ILLinkDirectory)ILLink.Substitutions.xml" />
   </ItemGroup>
-
   <ItemGroup>
     <Compile Include="System\Net\Http\ByteArrayContent.cs" />
     <Compile Include="System\Net\Http\ByteArrayHelpers.cs" />
@@ -662,20 +661,6 @@
   <ItemGroup Condition=" '$(TargetsBrowser)' == 'true'">
     <ProjectReference Include="$(LibrariesProjectRoot)System.Private.Runtime.InteropServices.JavaScript\src\System.Private.Runtime.InteropServices.JavaScript.csproj" />
   </ItemGroup>
-  <ItemGroup>
-    <Content Include="msquic.dll" Condition="Exists('msquic.dll')">
-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-      <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
-    </Content>
-    <Content Include="libmsquic.so" Condition="Exists('libmsquic.so')">
-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-      <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
-    </Content>
-    <Content Include="msquic.pdb" Condition="Exists('msquic.pdb')">
-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-      <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
-    </Content>
-  </ItemGroup>
   <ItemGroup>
     <None Include="Resources\SR.resx" />
   </ItemGroup>

src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/ConnectHelper.cs

@@ -7,6 +7,7 @@
 using System.Net.Quic.Implementations;
 using System.Net.Security;
 using System.Net.Sockets;
+using System.Runtime.Versioning;
 using System.Security.Cryptography.X509Certificates;
 using System.Threading;
 using System.Threading.Tasks;
@@ -100,6 +101,9 @@ private static async ValueTask<SslStream> EstablishSslConnectionAsyncCore(bool a
             return sslStream;
         }
 
+        [SupportedOSPlatform("windows")]
+        [SupportedOSPlatform("linux")]
+        [SupportedOSPlatform("macos")]
         public static async ValueTask<QuicConnection> ConnectQuicAsync(QuicImplementationProvider quicImplementationProvider, DnsEndPoint endPoint, SslClientAuthenticationOptions? clientAuthenticationOptions, CancellationToken cancellationToken)
         {
             QuicConnection con = new QuicConnection(quicImplementationProvider, endPoint, clientAuthenticationOptions);

src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/Http3Connection.cs

@@ -4,6 +4,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using System.Runtime.CompilerServices;
+using System.Runtime.Versioning;
 using System.Net.Quic;
 using System.IO;
 using System.Collections.Generic;
@@ -13,6 +14,9 @@
 
 namespace System.Net.Http
 {
+    [SupportedOSPlatform("windows")]
+    [SupportedOSPlatform("linux")]
+    [SupportedOSPlatform("macos")]
     internal sealed class Http3Connection : HttpConnectionBase, IDisposable
     {
         // TODO: once HTTP/3 is standardized, create APIs for this.

src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/Http3ConnectionException.cs

@@ -2,10 +2,14 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Runtime.Serialization;
+using System.Runtime.Versioning;
 
 namespace System.Net.Http
 {
     [Serializable]
+    [SupportedOSPlatform("windows")]
+    [SupportedOSPlatform("linux")]
+    [SupportedOSPlatform("macos")]
     internal sealed class Http3ConnectionException : Http3ProtocolException
     {
         public Http3ConnectionException(Http3ErrorCode errorCode)

src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/Http3ProtocolException.cs

@@ -2,10 +2,14 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Runtime.Serialization;
+using System.Runtime.Versioning;
 
 namespace System.Net.Http
 {
     [Serializable]
+    [SupportedOSPlatform("windows")]
+    [SupportedOSPlatform("linux")]
+    [SupportedOSPlatform("macos")]
     internal class Http3ProtocolException : Exception
     {
         public Http3ErrorCode ErrorCode { get; }

src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/Http3RequestStream.cs

@@ -10,11 +10,15 @@
 using System.Threading;
 using System.Threading.Tasks;
 using System.Runtime.CompilerServices;
+using System.Runtime.Versioning;
 using System.Net.Http.QPack;
 using System.Runtime.ExceptionServices;
 
 namespace System.Net.Http
 {
+    [SupportedOSPlatform("windows")]
+    [SupportedOSPlatform("linux")]
+    [SupportedOSPlatform("macos")]
     internal sealed class Http3RequestStream : IHttpHeadersHandler, IAsyncDisposable, IDisposable
     {
         private readonly HttpRequestMessage _request;

src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnectionPool.cs

@@ -14,6 +14,7 @@
 using System.Net.Sockets;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
+using System.Runtime.Versioning;
 using System.Security.Authentication;
 using System.Text;
 using System.Threading;
@@ -119,7 +120,11 @@ public HttpConnectionPool(HttpConnectionPoolManager poolManager, HttpConnectionK
             }
 
             _http2Enabled = _poolManager.Settings._maxHttpVersion >= HttpVersion.Version20;
-            _http3Enabled = _poolManager.Settings._maxHttpVersion >= HttpVersion.Version30 && (_poolManager.Settings._quicImplementationProvider ?? QuicImplementationProviders.Default).IsSupported;
+            // TODO: Replace with Platform-Guard Assertion Annotations once https://github.com/dotnet/runtime/issues/44922 is finished
+            if (OperatingSystem.IsLinux() || OperatingSystem.IsWindows() || OperatingSystem.IsMacOS())
+            {
+                _http3Enabled = _poolManager.Settings._maxHttpVersion >= HttpVersion.Version30 && (_poolManager.Settings._quicImplementationProvider ?? QuicImplementationProviders.Default).IsSupported;
+            }
 
             switch (kind)
             {
@@ -240,10 +245,14 @@ public HttpConnectionPool(HttpConnectionPoolManager poolManager, HttpConnectionK
                     _http3EncodedAuthorityHostHeader = QPackEncoder.EncodeLiteralHeaderFieldWithStaticNameReferenceToArray(H3StaticTable.Authority, hostHeader);
                 }
 
-                if (_http3Enabled)
+                // TODO: Replace with Platform-Guard Assertion Annotations once https://github.com/dotnet/runtime/issues/44922 is finished
+                if (OperatingSystem.IsLinux() || OperatingSystem.IsWindows() || OperatingSystem.IsMacOS())
                 {
-                    _sslOptionsHttp3 = ConstructSslOptions(poolManager, sslHostName);
-                    _sslOptionsHttp3.ApplicationProtocols = s_http3ApplicationProtocols;
+                    if (_http3Enabled)
+                    {
+                        _sslOptionsHttp3 = ConstructSslOptions(poolManager, sslHostName);
+                        _sslOptionsHttp3.ApplicationProtocols = s_http3ApplicationProtocols;
+                    }
                 }
             }
 
@@ -352,24 +361,28 @@ public byte[] Http2AltSvcOriginUri
                 }
             }
 
-            // Either H3 explicitly requested or secured upgraded allowed.
-            if (_http3Enabled && (request.Version.Major >= 3 || (request.VersionPolicy == HttpVersionPolicy.RequestVersionOrHigher && IsSecure)))
+            // TODO: Replace with Platform-Guard Assertion Annotations once https://github.com/dotnet/runtime/issues/44922 is finished
+            if (OperatingSystem.IsLinux() || OperatingSystem.IsWindows() || OperatingSystem.IsMacOS())
             {
-                HttpAuthority? authority = _http3Authority;
-                // H3 is explicitly requested, assume prenegotiated H3.
-                if (request.Version.Major >= 3 && request.VersionPolicy != HttpVersionPolicy.RequestVersionOrLower)
-                {
-                    authority = authority ?? _originAuthority;
-                }
-                if (authority != null)
+                // Either H3 explicitly requested or secured upgraded allowed.
+                if (_http3Enabled && (request.Version.Major >= 3 || (request.VersionPolicy == HttpVersionPolicy.RequestVersionOrHigher && IsSecure)))
                 {
-                    if (IsAltSvcBlocked(authority))
+                    HttpAuthority? authority = _http3Authority;
+                    // H3 is explicitly requested, assume prenegotiated H3.
+                    if (request.Version.Major >= 3 && request.VersionPolicy != HttpVersionPolicy.RequestVersionOrLower)
                     {
-                        return ValueTask.FromException<(HttpConnectionBase connection, bool isNewConnection)>(
-                            new HttpRequestException(SR.Format(SR.net_http_requested_version_cannot_establish, request.Version, request.VersionPolicy, 3)));
+                        authority = authority ?? _originAuthority;
                     }
+                    if (authority != null)
+                    {
+                        if (IsAltSvcBlocked(authority))
+                        {
+                            return ValueTask.FromException<(HttpConnectionBase connection, bool isNewConnection)>(
+                                new HttpRequestException(SR.Format(SR.net_http_requested_version_cannot_establish, request.Version, request.VersionPolicy, 3)));
+                        }
 
-                    return GetHttp3ConnectionAsync(request, authority, cancellationToken);
+                        return GetHttp3ConnectionAsync(request, authority, cancellationToken);
+                    }
                 }
             }
 
@@ -719,6 +732,9 @@ private void AddHttp2Connection(Http2Connection newConnection)
             }
         }
 
+        [SupportedOSPlatform("windows")]
+        [SupportedOSPlatform("linux")]
+        [SupportedOSPlatform("macos")]
         private async ValueTask<(HttpConnectionBase connection, bool isNewConnection)>
             GetHttp3ConnectionAsync(HttpRequestMessage request, HttpAuthority authority, CancellationToken cancellationToken)
         {

src/libraries/System.Net.Http/tests/TrimmingTests/HttpClientTest.cs

@@ -0,0 +1,33 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.IO;
+using System.Net.Http;
+using System.Threading.Tasks;
+
+class Program
+{
+    static async Task<int> Main(string[] args)
+    {
+        using var client = new HttpClient();
+        using var response = await client.GetAsync("https://www.microsoft.com");            
+        var result = await response.Content.ReadAsStringAsync();
+        Console.WriteLine(result);
+
+        const string quicDll = "System.Net.Quic.dll";
+        var quicDllExists = File.Exists(Path.Combine(AppContext.BaseDirectory, quicDll));
+
+        // TODO: Replace with Platform-Guard Assertion Annotations once https://github.com/dotnet/runtime/issues/44922 is finished
+        if (OperatingSystem.IsLinux() || OperatingSystem.IsWindows() || OperatingSystem.IsMacOS())
+        {
+            Console.WriteLine($"Expected {quicDll} is {(quicDllExists ? "present - OK" : "missing - BAD")}.");
+            return quicDllExists ? 100 : -1;
+        }
+        else
+        {
+            Console.WriteLine($"Unexpected {quicDll} is {(quicDllExists ? "present - BAD" : "missing - OK")}.");
+            return quicDllExists ? -1 : 100;
+        }
+    }
+}

src/libraries/System.Net.Http/tests/TrimmingTests/System.Net.Http.TrimmingTests.proj

@@ -0,0 +1,9 @@
+<Project DefaultTargets="Build">
+  <Import Project="$([MSBuild]::GetPathOfFileAbove(Directory.Build.props))" />
+
+  <ItemGroup>
+    <TestConsoleAppSourceFiles Include="HttpClientTest.cs" />
+  </ItemGroup>
+
+  <Import Project="$([MSBuild]::GetPathOfFileAbove(Directory.Build.targets))" />
+</Project>