MetadataUpdateHandlerTests.NoActions: IOException file used by another process (Program.cs)

[MichaelSimons]

Build Information

Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1488557
Leg Name: TestBuild: linux (x64) - ubuntu.2204.amd64.open (dotnet-watch.Tests.dll.5)

Error Details

Flaky failure seen while running the dotnet-watch Hot Reload tests. The test MetadataUpdateHandlerTests.NoActions fails because the watched process never emits the expected output line — the underlying cause is a file-lock race on the test app's Program.cs (IOException: ... because it is being used by another process). The work item exits with code 2.

It is flaky: on build 1488557 (PR #55000) it failed on one linux attempt and passed on the retried attempt of the same commit. This is the same file-lock race family as #55098 (RuntimeProcessLauncherTests.RelaunchOnCrash), but a different test, so #55098's pattern does not match it, and the timeout KBE #40074 does not match it either (this is an assertion failure, not a Command timed out work item).

failed NoActions (24s 313ms)
  Assertion failed. Expected value to not be null.
  Assert.IsNotNull(line)
    at Microsoft.DotNet.Watch.UnitTests.AwaitableProcess.GetRequiredOutputLineAsync(Predicate`1 selector) in /_/test/Microsoft.DotNet.HotReload.Test.Utilities/AwaitableProcess.cs:122
    at Microsoft.DotNet.Watch.UnitTests.WatchableApp.WaitUntilOutputContains(String text, String testPath, Int32 testLine) in /_/test/Microsoft.DotNet.HotReload.Test.Utilities/WatchableApp.cs:85
    at Microsoft.DotNet.Watch.UnitTests.MetadataUpdateHandlerTests.NoActions() in /_/test/dotnet-watch.Tests/HotReload/MetadataUpdateHandlerTests.cs:37

dotnet watch ❌ An unexpected error occurred: System.IO.IOException: The process cannot access the file '.../NoActions_Met---XXXXXXXX/Program.cs' because it is being used by another process.

Example occurrence: PR #55000, build 1488557 (dotnet-watch.Tests.dll.5, exit code 2).

Error Message

{
    "ErrorMessage": [
        "MetadataUpdateHandlerTests.NoActions",
        "The process cannot access the file"
    ],
    "BuildRetry": true,
    "ExcludeConsoleLog": false
}

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1488557
Error message validated: [MetadataUpdateHandlerTests.NoActions The process cannot access the file]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 7/7/2026 1:28:22 PM UTC

Report

Build	Repository	Test	Pull Request
1488557	dotnet/sdk	NoActions	#55000

Summary

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