Use alpine pwsh images in TestPwshGitCredHelper

Igorrequested to merge
fix/pwsh-cred-helper-test-alpine into main

What does this MR do?

Switches the linux images used by TestPwshGitCredHelper from the debian-11 variants of mcr.microsoft.com/powershell to the alpine variants of the same pwsh versions (7.1.5, 7.2, 7.3), and installs git with apk add instead of apt-get.

Why was this MR needed?

Debian 11 (bullseye) left LTS on 2026-08-31 and its security repository was removed from security.debian.org. In the *-debian-11 images apt-get update now fails (hidden by Out-Null), apt-get install git falls back to the package lists baked into the image and gets 404s, and the test fails with The term 'git' is not recognized. Impact, from the integration test with race 2/4 job history:

  • Last clean pass: 2026-09-04 ~13:00 UTC. First failure: 2026-09-04 13:37 UTC (pipeline 2820468773). Fixed by this MR at 2026-09-07 10:08 UTC, so just under 3 days.
  • 47 integration test with race 2/4 jobs failed on TestPwshGitCredHelper across 30 pipelines: 4 on main (push) and 26 MR pipelines spanning 9 MRs (6911, 7179, 7185, 7283, 7292, 7297, 7301, 7302, 7304). Example: https://gitlab.com/gitlab-org/gitlab-runner/-/jobs/16341129320.
  • On 2026-09-04 the Debian CDN was still inconsistent, so gotestsum reruns rescued a few jobs on the second or third attempt (e.g. job 16314447618 on main). From 2026-09-05 every job that ran the test failed.

There are no debian-12 images for pwsh 7.1 and 7.2, so moving to a newer Debian is not an option for all three versions. Alpine keeps repositories for EOL releases reachable on dl-cdn.alpinelinux.org, so the test does not depend on a distro support window again. The repo already uses an alpine pwsh image for common.TestPwshImage. The windows image mapping is unchanged (those tests are skipped anyway).

What's the best way to test this MR?

The integration test with race jobs in this pipeline. Locally: go test -race -run TestPwshGitCredHelper ./executors/docker/ with a Docker daemon available.

What are the relevant issue numbers?

None; the failure was reported via the job link above.

Edited by Igor

Merge request reports