Fix deadlock in the completion process when the send buffer is full.

src/YetAnotherHttpHandler/NativeRuntime.cs

@@ -9,7 +9,7 @@ internal class NativeRuntime
         public static NativeRuntime Instance { get; } = new NativeRuntime();
 
         private readonly object _lock = new object();
-        private int _refCount;
+        internal /* for unit testing */ int _refCount;
         private YahaRuntimeSafeHandle? _handle;
 
         private NativeRuntime()

src/YetAnotherHttpHandler/RequestContext.cs

@@ -128,10 +128,30 @@ private async Task RunReadRequestLoopAsync(CancellationToken cancellationToken)
             }
         }
 
-        private unsafe void WriteBody(Span<byte> data)
+        private void WriteBody(Span<byte> data)
+        {
+            var retryInterval = 16; //ms
+            var retryAfter = 0;
+
+            while (!_cancellationTokenSource.IsCancellationRequested && !TryWriteBody(data))
+            {
+                // TODO:
+                retryAfter += retryInterval;
+                Thread.Sleep(Math.Min(1000, retryAfter));
+            }
+        }
+
+        private unsafe bool TryWriteBody(Span<byte> data)
         {
             lock (_handleLock)
             {
+                if (!_handle.IsAllocated)
+                {
+                    // If the handle has been already released, the request is fully completed.
+                    ThrowHelper.ThrowOperationCanceledException();
+                    return true; // the method never return from here.
+                }
+
                 Debug.Assert(_handle.IsAllocated);
 
                 if (YahaEventSource.Log.IsEnabled()) YahaEventSource.Log.Trace($"[ReqSeq:{_requestSequence}:State:0x{Handle:X}] Sending the request body: Length={data.Length}");
@@ -146,8 +166,6 @@ private unsafe void WriteBody(Span<byte> data)
                     var ctx = _ctxHandle.DangerousGet();
                     var requestContext = _requestContextHandle.DangerousGet();
 
-                    var retryInterval = 16; //ms
-                    var retryAfter = 0;
                     while (!_requestBodyCompleted)
                     {
                         // If the internal buffer is full, yaha_request_write_body returns false. We need to wait until ready to send bytes again.
@@ -161,14 +179,11 @@ private unsafe void WriteBody(Span<byte> data)
                         {
                             if (YahaEventSource.Log.IsEnabled()) YahaEventSource.Log.Trace($"[ReqSeq:{_requestSequence}:State:0x{Handle:X}] Failed to write the request body. Because the request has been completed.");
                             ThrowHelper.ThrowOperationCanceledException();
-                            return;
+                            return true; // the method never return from here.
                         }
 
                         if (YahaEventSource.Log.IsEnabled()) YahaEventSource.Log.Trace($"[ReqSeq:{_requestSequence}:State:0x{Handle:X}] Send buffer is full.");
-
-                        // TODO:
-                        retryAfter += retryInterval;
-                        Thread.Sleep(Math.Min(1000, retryAfter));
+                        return false;
                     }
 #if DEBUG
                     // Fill memory so that data corruption can be detected on debug build.
@@ -188,6 +203,8 @@ private unsafe void WriteBody(Span<byte> data)
                     }
                 }
             }
+
+            return true;
         }
 
         private unsafe void TryCompleteBody(Exception? exception = default)

src/YetAnotherHttpHandler/ResponseContext.cs

@@ -26,7 +26,7 @@ internal ResponseContext(HttpRequestMessage requestMessage, RequestContext reque
             _requestContext = requestContext;
             _responseTask = new TaskCompletionSource<HttpResponseMessage>(TaskCreationOptions.RunContinuationsAsynchronously);
             _cancellationToken = cancellationToken;
-            _tokenRegistration = cancellationToken.Register((state) =>
+            _tokenRegistration = cancellationToken.Register(static (state) =>
             {
                 ((ResponseContext)state!).Cancel();
             }, this);

test/YetAnotherHttpHandler.Test/ClientCertificateTest.cs

@@ -41,7 +41,7 @@ public async Task NotSet()
     {
         // Arrange
         await using var server = await LaunchServerAsync<TestServerForHttp1AndHttp2>();
-        var httpHandler = new YetAnotherHttpHandler()
+        using var httpHandler = new YetAnotherHttpHandler()
         {
             //ClientAuthCertificates = File.ReadAllText("./Certificates/client.crt"),
             //ClientAuthKey = File.ReadAllText("./Certificates/client.key"),
@@ -63,7 +63,7 @@ public async Task UseClientCertificate()
     {
         // Arrange
         await using var server = await LaunchServerAsync<TestServerForHttp1AndHttp2>();
-        var httpHandler = new YetAnotherHttpHandler()
+        using var httpHandler = new YetAnotherHttpHandler()
         {
             ClientAuthCertificates = File.ReadAllText("./Certificates/client.crt"),
             ClientAuthKey = File.ReadAllText("./Certificates/client.key"),
@@ -85,7 +85,7 @@ public async Task Invalid()
     {
         // Arrange
         await using var server = await LaunchServerAsync<TestServerForHttp1AndHttp2>();
-        var httpHandler = new YetAnotherHttpHandler()
+        using var httpHandler = new YetAnotherHttpHandler()
         {
             ClientAuthCertificates = File.ReadAllText("./Certificates/client_unknown.crt"), // CN=unknown.example.com
             ClientAuthKey = File.ReadAllText("./Certificates/client_unknown.key"),
@@ -106,7 +106,7 @@ public async Task Reference_SocketHttpHandler_NotSet()
     {
         // Arrange
         await using var server = await LaunchServerAsync<TestServerForHttp1AndHttp2>();
-        var httpHandler = new SocketsHttpHandler();
+        using var httpHandler = new SocketsHttpHandler();
         httpHandler.SslOptions.RemoteCertificateValidationCallback = (sender, certificate, chain, errors) => true;
         var httpClient = new HttpClient(httpHandler);
 
@@ -123,7 +123,7 @@ public async Task Reference_SocketHttpHandler_UseClientCertificate()
     {
         // Arrange
         await using var server = await LaunchServerAsync<TestServerForHttp1AndHttp2>();
-        var httpHandler = new SocketsHttpHandler();
+        using var httpHandler = new SocketsHttpHandler();
         httpHandler.SslOptions.RemoteCertificateValidationCallback = (sender, certificate, chain, errors) => true;
         httpHandler.SslOptions.ClientCertificates = new X509CertificateCollection()
         {
@@ -145,7 +145,7 @@ public async Task Reference_SocketHttpHandler_Invalid()
     {
         // Arrange
         await using var server = await LaunchServerAsync<TestServerForHttp1AndHttp2>();
-        var httpHandler = new SocketsHttpHandler();
+        using var httpHandler = new SocketsHttpHandler();
         httpHandler.SslOptions.RemoteCertificateValidationCallback = (sender, certificate, chain, errors) => true;
         httpHandler.SslOptions.ClientCertificates = new X509CertificateCollection()
         {

test/YetAnotherHttpHandler.Test/Http1Test.cs

@@ -1,18 +1,11 @@
 using System.IO.Pipelines;
 using System.Net;
-using System.Runtime.ExceptionServices;
-using _YetAnotherHttpHandler.Test.Helpers;
 using Xunit.Abstractions;
-using Xunit.Sdk;
 
 namespace _YetAnotherHttpHandler.Test;
 
-public class Http1Test : UseTestServerTestBase
+public class Http1Test(ITestOutputHelper testOutputHelper) : UseTestServerTestBase(testOutputHelper)
 {
-    public Http1Test(ITestOutputHelper testOutputHelper) : base(testOutputHelper)
-    {
-    }
-
     [Fact]
     public async Task FailedToConnect()
     {

test/YetAnotherHttpHandler.Test/Http2ClearTextTest.cs

@@ -5,12 +5,8 @@
 
 namespace _YetAnotherHttpHandler.Test;
 
-public class Http2ClearTextTest : Http2TestBase
+public class Http2ClearTextTest(ITestOutputHelper testOutputHelper) : Http2TestBase(testOutputHelper)
 {
-    public Http2ClearTextTest(ITestOutputHelper testOutputHelper) : base(testOutputHelper)
-    {
-    }
-
     protected override YetAnotherHttpHandler CreateHandler()
     {
         return new YetAnotherHttpHandler() { Http2Only = true };

test/YetAnotherHttpHandler.Test/Http2Test.cs

@@ -8,12 +8,8 @@
 namespace _YetAnotherHttpHandler.Test;
 
 [OSSkipCondition(OperatingSystems.MacOSX)] // .NET 7 or earlier does not support ALPN on macOS.
-public class Http2Test : Http2TestBase
+public class Http2Test(ITestOutputHelper testOutputHelper) : Http2TestBase(testOutputHelper)
 {
-    public Http2Test(ITestOutputHelper testOutputHelper) : base(testOutputHelper)
-    {
-    }
-
     protected override YetAnotherHttpHandler CreateHandler()
     {
         // Use self-signed certificate for testing purpose.
@@ -47,7 +43,7 @@ public async Task SelfSignedCertificate_NotTrusted()
     {
         // Arrange
         await using var server = await LaunchServerAsync<TestServerForHttp1AndHttp2>();
-        var httpHandler = new YetAnotherHttpHandler() { SkipCertificateVerification = false }; // We need to verify server certificate.
+        using var httpHandler = new YetAnotherHttpHandler() { SkipCertificateVerification = false }; // We need to verify server certificate.
         var httpClient = new HttpClient(httpHandler);
 
         // Act
@@ -63,7 +59,7 @@ public async Task SelfSignedCertificate_NotTrusted_SkipValidation()
     {
         // Arrange
         await using var server = await LaunchServerAsync<TestServerForHttp1AndHttp2>();
-        var httpHandler = new YetAnotherHttpHandler() { SkipCertificateVerification = true };
+        using var httpHandler = new YetAnotherHttpHandler() { SkipCertificateVerification = true };
         var httpClient = new HttpClient(httpHandler);
 
         // Act
@@ -80,7 +76,7 @@ public async Task SelfSignedCertificate_Trusted_CustomRootCA()
     {
         // Arrange
         await using var server = await LaunchServerAsync<TestServerForHttp1AndHttp2>();
-        var httpHandler = new YetAnotherHttpHandler()
+        using var httpHandler = new YetAnotherHttpHandler()
         {
             // We need to verify server certificate.
             SkipCertificateVerification = false,

test/YetAnotherHttpHandler.Test/Http2TestBase.cs

@@ -10,12 +10,8 @@
 
 namespace _YetAnotherHttpHandler.Test;
 
-public abstract class Http2TestBase : UseTestServerTestBase
+public abstract class Http2TestBase(ITestOutputHelper testOutputHelper) : UseTestServerTestBase(testOutputHelper)
 {
-    protected Http2TestBase(ITestOutputHelper testOutputHelper) : base(testOutputHelper)
-    {
-    }
-
     protected abstract YetAnotherHttpHandler CreateHandler();
     protected abstract Task<TestWebAppServer> LaunchServerAsyncCore<T>(Action<WebApplicationBuilder>? configure = null) where T : ITestServerBuilder;
 

test/YetAnotherHttpHandler.Test/TestServerForHttp1AndHttp2.cs

@@ -164,6 +164,19 @@ public static WebApplication BuildApplication(WebApplicationBuilder builder)
             }
             return Results.Empty;
         });
+        app.MapPost("/post-never-read", async (HttpContext httpContext) =>
+        {
+            // Send status code and response headers.
+            httpContext.Response.Headers["x-header-1"] = "foo";
+            httpContext.Response.StatusCode = (int)HttpStatusCode.OK;
+            await httpContext.Response.BodyWriter.FlushAsync();
+
+            while (!httpContext.RequestAborted.IsCancellationRequested)
+            {
+                await Task.Delay(100);
+            }
+            return Results.Empty;
+        });
 
         // HTTP/2
         app.MapGet("/error-reset", (HttpContext httpContext) =>

test/YetAnotherHttpHandler.Test/YetAnotherHttpHandlerTest.cs

@@ -1,8 +1,16 @@
 using Cysharp.Net.Http;
+using System.IO.Pipelines;
+using System.Net;
+using System.Net.Http.Headers;
+using Xunit.Abstractions;
 
 namespace _YetAnotherHttpHandler.Test;
 
-public class YetAnotherHttpHandlerTest
+[CollectionDefinition(nameof(YetAnotherHttpHandlerTest), DisableParallelization = true)]
+public class YetAnotherHttpHandlerTestCollection;
+
+[Collection(nameof(YetAnotherHttpHandlerTest))]
+public class YetAnotherHttpHandlerTest(ITestOutputHelper testOutputHelper) : UseTestServerTestBase(testOutputHelper)
 {
     [Fact]
     public async Task Disposed()
@@ -18,4 +26,68 @@ public async Task Disposed()
         // Assert
         Assert.IsType<ObjectDisposedException>(ex);
     }
+
+    [Fact]
+    public async Task DisposeHandler_During_SendBuffer_Is_Full()
+    {
+        GC.Collect();
+        GC.Collect();
+        GC.Collect();
+        GC.Collect();
+
+        var runtimeHandle = NativeRuntime.Instance.Acquire();
+
+        // To prevent references remaining from local variables, make it a local function.
+        async Task RunAsync()
+        {
+            // Arrange
+            var httpHandler = new YetAnotherHttpHandler() { Http2Only = true };
+            var httpClient = new HttpClient(httpHandler);
+            await using var server = await LaunchServerAsync<TestServerForHttp1AndHttp2>(TestWebAppServerListenMode.InsecureHttp2Only);
+
+            // Act
+            var pipe = new Pipe();
+            var writeTask = Task.Run(async () =>
+            {
+                var buffer = new byte[1024 * 1024];
+                while (true)
+                {
+                    await pipe.Writer.WriteAsync(buffer);
+                }
+            });
+            var content = new StreamContent(pipe.Reader.AsStream());
+            content.Headers.ContentType = MediaTypeHeaderValue.Parse("application/octet-stream");
+            var request = new HttpRequestMessage(HttpMethod.Post, $"{server.BaseUri}/post-never-read")
+            {
+                Version = HttpVersion.Version20,
+                Content = content,
+            };
+            var response = await httpClient.SendAsync(request, HttpCompletionOption.ResponseHeadersRead).WaitAsync(TimeoutToken);
+            await Task.Delay(TimeSpan.FromSeconds(5)); // Wait for the send buffer to overflow.
+
+            // Decrease the reference count of manually held internal handles for direct observation.
+            NativeRuntime.Instance.Release();
+
+            // Dispose all related resources.
+            request.Dispose();
+            response.Dispose();
+            httpHandler.Dispose();
+            httpClient.Dispose();
+        }
+
+        await RunAsync();
+
+        // Run Finalizer.
+        await Task.Delay(100);
+        GC.Collect();
+        GC.Collect();
+        GC.Collect();
+        GC.Collect();
+        await Task.Delay(100);
+
+        // Assert
+        Assert.Equal(0, NativeRuntime.Instance._refCount);
+        Assert.True(runtimeHandle.IsClosed);
+    }
+
 }