[Known Build Error] ProjectUpdateInProcTests.ProjectAndSourceFileChange_AddProjectReference timing failure

[lewing]

Build Information

Build: https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1362100
Build error leg or test failing: dotnet-watch.Tests.dll.9
Pull request: #53656

Error Message

{
  "ErrorMessage": "Failed Microsoft.DotNet.Watch.UnitTests.ProjectUpdateInProcTests.ProjectAndSourceFileChange_AddProjectReference",
  "ErrorPattern": "",
  "BuildRetry": true,
  "ExcludeConsoleLog": false
}

Details

ProjectAndSourceFileChange_AddProjectReference is an in-process dotnet-watch hot reload test that adds a project reference and expects exactly 1 update notification. It fails intermittently with Assert.Equal: Expected 1, Actual 0 — the hot reload notification did not arrive before the assertion timeout.

This is a timing-dependent test: it launches dotnet-watch, modifies files, and waits for hot reload to detect the change. On busy Helix machines the notification can be delayed past the timeout.

The test uses WatchAppWithProjectDeps (a console app, not WASM) and does not involve any WASM SDK targets.

Stack trace:

Assert.Equal() Failure: Values differ
Expected: 1
Actual:   0
   at ProjectUpdateInProcTests.ProjectAndSourceFileChange_AddProjectReference()
   in /_/test/dotnet-watch.Tests/HotReload/ProjectUpdateInProcTests.cs:line 122

Sample log: https://helix.dot.net/api/2019-06-17/jobs/1993ef9a-2a5b-4567-b9f4-ce1e9631d183/workitems/dotnet-watch.Tests.dll.9/console

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1362100
Error message validated: [Failed Microsoft.DotNet.Watch.UnitTests.ProjectUpdateInProcTests.ProjectAndSourceFileChange_AddProjectReference]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 4/1/2026 6:04:40 PM UTC

Report

Build	Definition	Test	Pull Request
1375258	dotnet/sdk	Microsoft.DotNet.Watch.UnitTests.Program_GetProjectOptionsTests.FilePathOptionTakesPrecedenceOverProjectPath	#53827
1374363	dotnet/sdk	dotnet-watch.Tests.dll.6.WorkItemExecution	#51560
1373478	dotnet/sdk	Microsoft.DotNet.Watch.UnitTests.Program_GetProjectOptionsTests.ProjectFile_RejectedExtension	#53800
1373171	dotnet/sdk	dotnet-watch.Tests.dll.6.WorkItemExecution	#53759
1371905	dotnet/sdk	Microsoft.DotNet.Watch.UnitTests.ProjectGraphFactoryTests.VirtualProject_ProjectDirective	#53760
1365468	dotnet/sdk	dotnet-watch.Tests.dll.9.WorkItemExecution	#53680
1362100	dotnet/sdk	dotnet-watch.Tests.dll.9.WorkItemExecution	#53656

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
1	5	7