[Known Build Error] BackCompatibilityPublish_Hosted_Works fails with file lock on .gz compression temp #53660
Description
Build Information
Build: https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1362100
Build error leg or test failing: Microsoft.NET.Sdk.BlazorWebAssembly.Tests.dll.1
Pull request: #53656
Error Message
{
"ErrorMessage": "",
"ErrorPattern": "BlazorWebAssembly\\.5_0\\.targets.*error : The process cannot access the file.*compress.*\\.gz.*because it is being used by another process",
"BuildRetry": true,
"ExcludeConsoleLog": false
}Details
StaticWebAssets_BackCompatibilityPublish_Hosted_Works fails during the legacy .NET 5 compression step (BlazorWebAssembly.5_0.targets line 650) with a file lock on .gz temp files in obj/Debug/net5/compress/. This is the back-compat path for pre-net6.0 WASM clients hosted by a modern server.
The 5_0.targets compression step writes .gz files that may be locked by parallel test execution or antivirus on Windows Helix machines.
Sample error:
Microsoft.NET.Sdk.BlazorWebAssembly.5_0.targets(650,5): error : The process cannot access the file
'...\blazorwasm\obj\Debug\net5\compress\8TBK5+sk.gz' because it is being used by another process.
Related: #50784, #33956 (similar file lock patterns)
Known issue validation
Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1362100
Error message validated: [BlazorWebAssembly\.5_0\.targets.*error : The process cannot access the file.*compress.*\.gz.*because it is being used by another process]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 4/1/2026 6:04:17 PM UTC
Report
Summary
| 24-Hour Hit Count | 7-Day Hit Count | 1-Month Count |
|---|---|---|
| 7 | 10 | 10 |