ci: mirror linked issues' priority label on PRs

[julian-risch]

Related Issues

• None. I suggest to copy the priority label (P0–P3) from the issues a PR links onto the PR so that we sort PRs we need to review by priority.

Proposed Changes:

New workflow priority_label_sync.yml that copies the priority label (P0–P3) from the issues a PR links onto the PR:

• PR opened, reopened, or description edited (pull_request_target): labels the PR from its linked issues. This covers Fixes #123 in the description at open time, and issues linked later by editing the description.
• Priority label added to or removed from an issue (issues: labeled/unlabeled, filtered to P0–P3): re-syncs every open PR that links that issue. An issue that gets its priority after the PR was opened, or whose priority changes, updates the PR.
• Daily sweep at 05:00 UTC plus workflow_dispatch: re-syncs all open PRs. This catches issues linked through the "Development" sidebar, because GitHub sends no event for those links.

Rules for edge cases:

• If the linked issues have different priorities, the PR gets the highest one, and any other P* label on the PR is removed.
• Once no linked issue has a priority, or the PR no longer links an issue, the workflow removes the P* labels it added itself. It knows which ones those are from the PR's labeled events (actor github-actions). Priority labels set by hand stay.
• Every run compares the PR's labels with its linked issues' current labels instead of relying on the event payload. So the daily sweep also catches up on runs that were dropped or failed.
• Only issues in deepset-ai/haystack count, as in linked_issue_review.yml. Community members couldn't link private issues anyway.

How did you test it?

• Ran the sweep query read-only against the repo with gh api graphql successfully
• Ran the script on mocked synthetic PRs locally:
  • labels the workflow added are removed when the issue's priority is removed or the issue is unlinked
  • labels set by hand stay, including one re-added by hand after the workflow had added it
  • an issue's priority replaces a different label set by hand
  • a 404 on removeLabel is ignored
  • an error on one PR fails the run at the end without stopping the others

Notes for the reviewer

• Of 57 open PRs, 32 link an issue. The first run will add a label to 17 of them. We could consider enforcing that community PRs need to be linked to an issue but I see that as independent of this PR.
• pull_request_target gives the workflow write access on fork PRs too. This is safe because the workflow never checks out or runs PR code.

Checklist

• I have read the contributors guidelines and the code of conduct.
• I have updated the related issue with new insights and changes. — n/a, no related issue
• I have added unit tests and updated the docstrings. — n/a, CI workflow
• 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. — n/a, CI-only change
• I have run pre-commit hooks and fixed any issue. — n/a, no Python files changed; ran actionlint instead

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1 Skipped Deployment

Project	Deployment	Actions	Updated
haystack-docs	Ignored	Preview	Oct 7, 2026 5:50am UTC

[sjrl]

Looks good!