Microsoft.NET.Sdk.Razor.Tool.Tests Dispatcher_ProcessSimultaneousConnections_HitsKeepAliveTimeout: intermittent hang (test host hang-dump timeout, exit code 7)

[MichaelSimons]

Build Information

Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1524025
Build error leg or test failing: Microsoft.NET.Sdk.Razor.Tool.Tests work item Microsoft.NET.Sdk.Razor.Tool.Tests.dll.1 — test Dispatcher_ProcessSimultaneousConnections_HitsKeepAliveTimeout
Pull request: #55248

Description

Microsoft.NET.Sdk.Razor.Tool.Tests.Dispatcher_ProcessSimultaneousConnections_HitsKeepAliveTimeout intermittently hangs. The rest of the assembly finishes quickly (53 completed, 0 failed) and Dispatcher_ProcessSimultaneousConnections_HitsKeepAliveTimeout is the only test still running when the blame hang-dump timeout of 00:48:00 fires. A hang dump is collected for the dotnet process tree, the test host is killed (Test host crashed), and the Helix work item finishes with exit code 7, failing the Monitor Helix Jobs step and turning the whole build red.

This is a sibling failure to the hang-dump/exit-code-7 family previously tracked for other tests (e.g. #55430 HotReload_WithWebSocketCapability, #55258 LoggingTests.BinaryLogs, #55478 RenameSourceFile) — same mechanism, different test — so it is tracked separately with a test-specific pattern to avoid cross-matching. The failure is intermittent (passed on the automatic build retry / attempt 2), so it is tracked with BuildRetry: true.

The failure is unrelated to the PR where it was observed (#55248 "Skip test-runtime install on cross-architecture builds"), which does not touch the Razor tool.

Error Message

{
  "ErrorMessage": [
    "Hang dump timeout of",
    "] Dispatcher_ProcessSimultaneousConnections_HitsKeepAliveTimeout",
    "END OF WORK ITEM LOG: Command exited with 7"
  ],
  "BuildRetry": true,
  "ExcludeConsoleLog": false
}

The multi-line pattern requires, in order: the blame hang-dump timeout message, Dispatcher_ProcessSimultaneousConnections_HitsKeepAliveTimeout reported as still-running when the dump was taken, and the work item exiting with code 7 — which together uniquely identify a hang caused by this specific test without matching unrelated failures (e.g. the sibling HotReload_WithWebSocketCapability hang tracked by #55430). ExcludeConsoleLog is false because these lines appear only in the Helix work-item console log, not the AzDO build log.

Example occurrence

• PR Scope .editorconfig discovery to included files in dotnet format folder mode #55248, build 1524025 (attempt 1)
• Job: Windows x64 FullFramework - windows.amd64.vs2026.pre.scout.open
• Helix job 664360a8-0ff8-4bd8-906d-f019a9f92fcf, work item Microsoft.NET.Sdk.Razor.Tool.Tests.dll.1 (exit code 7, ran ~50m before the hang dump)
• Passed after the Build stage was manually retried (attempt 2).

Relevant console log excerpt:

running... 53 completed, 0 failed | active: Dispatcher_ProcessSimultaneousConnections_HitsKeepAliveTimeout
Hang dump timeout of '00:48:00' expired
The following tests were still running when dump was taken (format: [<time-elapsed-since-start>] <name>):
[00:48:00] Dispatcher_ProcessSimultaneousConnections_HitsKeepAliveTimeout
Test host crashed; recovered 53 test result(s) from the TRX streaming sidecar
...
['Microsoft.NET.Sdk.Razor.Tool.Tests.dll.1' END OF WORK ITEM LOG: Command exited with 7]

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1524025
Error message validated: [Hang dump timeout of ] Dispatcher_ProcessSimultaneousConnections_HitsKeepAliveTimeout END OF WORK ITEM LOG: Command exited with 7]
Result validation: ❌ Known issue did not match with the provided build.
Validation performed at: 7/28/2026 1:48:43 PM UTC

Report

Summary

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

[github-actions]

🎯 Agentic Issue Triage

Triage Assessment:

• 🏷️ Labels: Area-AspNetCore RazorSDK, BlazorWebAssemblySDK, StaticWebAssetsSDK Bug Test Debt
• 💻 Assignment: @davidwengier | @dotnet/razor-tooling
• 🟩 Confidence: high - Issue directly identifies the Razor tool test and matches the Area-AspNetCore / @dotnet/razor-tooling CODEOWNERS section.

Similar issues: #55430 (potentially related) #55478 (potentially related)

➡️ Summary: Dispatcher_ProcessSimultaneousConnections_HitsKeepAliveTimeout intermittently hangs, triggering a 48-minute hang-dump timeout and exit code 7 in CI. Investigate the keep-alive timeout logic in the Razor tool dispatcher to fix the flaky test.

Generated by 🏷️ Issue Triage for #55494 · 28.4 AIC · ⌖ 4.83 AIC · ⊞ 10K · ◷