8.0: Http2_IncorrectServerPreface_RequestFailsWithAppropriateHttpProtocolException failed

[jozkee]

Build Information

Build: https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1126730
Build error leg or test failing: System.Net.Http.Functional.Tests.SocketsHttpHandlerTest_Http2.Http2_IncorrectServerPreface_RequestFailsWithAppropriateHttpProtocolException
Pull request: #117878

Error Message

Fill the error message using step by step known issues guidance.

{
  "ErrorMessage": ["Expected: HttpProtocolError", "Actual:   Unknown"],
  "ErrorPattern": "",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1126730
Error message validated: [Expected: HttpProtocolError Actual: Unknown]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 8/19/2025 9:36:46 PM UTC

Report

Build	Definition	Test	Pull Request
1126730	dotnet/runtime	System.Net.Http.Functional.Tests.SocketsHttpHandlerTest_Http2.Http2_IncorrectServerPreface_RequestFailsWithAppropriateHttpProtocolException	#117878

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
0	0	1

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[MihuBot]

I'm a bot. Here is a possible related and/or duplicate issue (I may be wrong):

• [Test Failure] Http2_IncorrectServerPreface_RequestFailsWithAppropriateHttpProtocolException #92647

[ManickaP]

So there's also many re-runs of this test in 8.0 branches. Doesn't happen on anything newer. So it seems it's been mitigated with #94112. We could back-port the fix in 8.0 branch.