Summary
The mutation-testing workflow's Run setup commands step fails when sudo apt-get update errors out on the hosted runner's preconfigured Microsoft package repositories (packages.microsoft.com), even though none of those repositories' packages are actually needed by the workflow.
Run details
- Run 29497190523, scheduled, 2026-07-16, FAILURE, ~38.4 minutes overall (the failing step itself completed in well under a minute).
- Failing step:
Run setup commands (sudo apt-get update), exit code 100.
Root cause
Err:6 https://packages.microsoft.com/repos/azure-cli noble InRelease
403 Forbidden [IP: 13.107.213.70 443]
Err:8 https://packages.microsoft.com/ubuntu/24.04/prod noble InRelease
403 Forbidden [IP: 13.107.213.70 443]
...
E: Failed to fetch https://packages.microsoft.com/repos/azure-cli/dists/noble/InRelease 403 Forbidden [IP: 13.107.213.70 443]
E: The repository 'https://packages.microsoft.com/repos/azure-cli noble InRelease' is no longer signed.
E: Failed to fetch https://packages.microsoft.com/ubuntu/24.04/prod/dists/noble/InRelease 403 Forbidden [IP: 13.107.213.70 443]
E: The repository 'https://packages.microsoft.com/ubuntu/24.04/prod noble InRelease' is no longer signed.
##[error]Process completed with exit code 100.
The hosted GitHub Actions runner image preinstalls azure-cli and Microsoft-product apt sources. When Microsoft's package mirror returns 403 (an intermittent upstream condition outside axinite's control), apt-get update fails outright and takes the whole apt-get install -y clang mold step down with it, even though clang and mold come from the standard Ubuntu archive, not from Microsoft's repositories.
Proposed next step
Make the setup step resilient to this class of unrelated, third-party mirror failure: remove the Microsoft apt source list files (/etc/apt/sources.list.d/azure-cli.list, /etc/apt/sources.list.d/microsoft-prod.list, or equivalent) before running apt-get update, or restrict apt-get update to only the archives actually needed. This is a common hosted-runner flakiness workaround and should stop this class of setup failure recurring.
Summary
The mutation-testing workflow's
Run setup commandsstep fails whensudo apt-get updateerrors out on the hosted runner's preconfigured Microsoft package repositories (packages.microsoft.com), even though none of those repositories' packages are actually needed by the workflow.Run details
Run setup commands(sudo apt-get update), exit code 100.Root cause
The hosted GitHub Actions runner image preinstalls
azure-cliand Microsoft-product apt sources. When Microsoft's package mirror returns 403 (an intermittent upstream condition outside axinite's control),apt-get updatefails outright and takes the wholeapt-get install -y clang moldstep down with it, even though clang and mold come from the standard Ubuntu archive, not from Microsoft's repositories.Proposed next step
Make the setup step resilient to this class of unrelated, third-party mirror failure: remove the Microsoft apt source list files (
/etc/apt/sources.list.d/azure-cli.list,/etc/apt/sources.list.d/microsoft-prod.list, or equivalent) before runningapt-get update, or restrictapt-get updateto only the archives actually needed. This is a common hosted-runner flakiness workaround and should stop this class of setup failure recurring.