In .NET 9 preview 5 blazor WASM with chromium browsers, when using request streaming, HttpRequestException is thrown unexpectedly if a response is sent before the stream is fully sent to the server

[Gabriel123N]

Description

While trying the new SetBrowserRequestStreamingEnabled feature for ``HttpRequestMessage` in .NET9 Blazor WASM, I have noticed a blocking behaviour when returning non-success status code from my API calls while streaming something during the request.

Instead of returning a HttpResponseMessage that I can manipulate when returning non 2xx codes, the SendAsync method simply triggers a HttpRequestException.

After more tests, I have found that it is happening with any status code as long as the response is sent before the body is fully streamed to the server. I also believe this issue is only happening on Chromium browsers as Firefox is following the expected behaviour below.

Reproduction Steps

• Pull the following repositoy: https://github.com/Gabriel123N/BlazorStreamingException
• Start the server project and open the blazor app in your browser
• Click on the input file element and choose a file smaller than 128 000Kb
• Open the console. You should see the following line printed there Error message is "Bad request message returned"
• Check-in the checkbox next to the input element
• Click on the input element and choose a file again
• A stack trace of the exception should be printed inside the console

Expected behavior

Like when request streaming is disabled, no exception is thrown and I can manipulate the response as wanted.

Actual behavior

An exception is thrown on the SendAsync method call.

Regression?

No response

Known Workarounds

The server must read the entirety of the body

Configuration

• Microsoft.NETCore.App 9.0.0-preview.5.24306.7
• Windows
• x64
• Chrome and Edge.

Other information

Most likely linked to a missing exception handling there #91699

If I change the post endpoint to the following code to make sure that the request stream is fully read, no exception is thrown.

app.MapPost("/api/test",async (HttpRequest request) =>
        {
            var ms = new MemoryStream();
            await request.Body.CopyToAsync(ms);
            await Task.Delay(1000);
            return Results.BadRequest("Bad request message returned");
        });

Stack trace:

Error: System.Net.Http.HttpRequestException: Error
 ---> Error
   --- End of inner exception stack trace ---
   at System.Net.Http.BrowserHttpInterop.CancellationHelper(Task promise, CancellationToken cancellationToken, JSObject jsController)
   at System.IO.Stream.<CopyToAsync>g__Core|27_0(Stream source, Stream destination, Int32 bufferSize, CancellationToken cancellationToken)
   at System.Net.Http.StreamToStreamCopy.<CopyAsync>g__DisposeSourceAsync|1_0(Task copyTask, Stream source)
   at System.Net.Http.HttpContent.<CopyToAsync>g__WaitAsync|56_0(ValueTask copyTask)
   at System.Net.Http.BrowserHttpController.CallFetch(upload)
   at Microsoft.Extensions.Http.Logging.LoggingHttpMessageHandler.<SendCoreAsync>g__Core|5_0(HttpRequestMessage request, Boolean useAsync, CancellationToken cancellationToken)
   at Microsoft.Extensions.Http.Logging.LoggingScopeHttpMessageHandler.<SendCoreAsync>g__Core|5_0(HttpRequestMessage request, Boolean useAsync, CancellationToken cancellationToken)
   at System.Net.Http.HttpClient.<SendAsync>g__Core|83_0(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationTokenSource cts, Boolean disposeCts, CancellationTokenSource pendingRequestsCts, CancellationToken originalCancellationToken)

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[maraf]

cc @pavelsavara