ci: fix stable version matching for Docker

[anakin87]

Related Issues

In #10387, we attempted to tag Docker images for Haystack releases as stable.

Unfortunately, when releasing 2.23, this did not work:

• https://hub.docker.com/r/deepset/haystack/tags
• related workflow run: https://github.com/deepset-ai/haystack/actions/runs/21391303215/job/61578641842

The issue is caused by an incorrect version match: [[ "v2.23.0" =~ ^2\.[0-9]+\.[0-9]+$ ]].

Proposed Changes:

• fix the pattern for matching a stable version (add "v" prefix)
• add debug output to workflow

How did you test it?

Docker release worklow was triggered in this PR with temporary workarounds: https://github.com/deepset-ai/haystack/actions/runs/21434580424/job/61722024574

The resolved bake definition includes the expected stable tag:

{
    "group": {
      "default": {
        "targets": [
          "base"
        ]
      }
    },
    "target": {
      "base": {
        "context": ".",
        "dockerfile": "Dockerfile.base",
        "args": {
          "base_image": "python:3.12-slim",
          "build_image": "python:3.12-slim",
          "haystack_version": "main"
        },
        "tags": [
          "deepset/haystack:base-pr-10459",
          "deepset/haystack:stable"  ### NOTE THE TAG. 
          # THIS TAG WAS MISSING IN https://github.com/deepset-ai/haystack/actions/runs/21391303215/job/61578641842
        ],
        "platforms": [
          "linux/amd64"
        ],
        "output": [
          {
            "type": "docker"
          }
        ]
      }
    }
  }

Notes for the reviewer

We will only be able to publish the stable tag with the next release (2.24.0).
This seems like the cleanest solution.

Checklist

• I have read the contributors guidelines and the code of conduct.
• I have updated the related issue with new insights and changes.
• I have added unit tests and updated the docstrings.
• I've used one of the conventional commit types for my PR title: fix:, feat:, build:, chore:, ci:, docs:, style:, refactor:, perf:, test: and added ! in case the PR includes breaking changes.
• I have documented my code.
• I have added a release note file, following the contributors guidelines.
• I have run pre-commit hooks and fixed any issue.

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1 Skipped Deployment

Project	Deployment	Review	Updated (UTC)
haystack-docs	Ignored	Preview	Jan 28, 2026 10:33am

[sjrl]

Thanks for catching this!