Extend the external PR gate to verify that the PR author is actually
assigned to the issue they reference. Previously, anyone could link to
any open issue with `Fixes #NNN` to pass the check — this closes the
loophole by fetching each linked issue via the GitHub API and comparing
assignees against the PR author (case-insensitive). The bot comment now
adapts its message based on which check failed, and updates in place if
the failure reason changes on a re-check.
## Changes
- Add assignee validation in the `check-link` step: after parsing issue
numbers from the PR body, fetch each via `github.rest.issues.get` and
check if the PR author appears in `assignees` — short-circuits on first
match
- Gate all downstream steps (`missing-issue-link` label add/remove,
comment, `setFailed`) on both `has-link` and `is-assigned` outputs
- Serve a distinct bot comment when the issue link exists but the author
isn't assigned, directing them to request assignment from a maintainer
- Update the existing marker comment in place (via `updateComment`) when
the failure reason changes between re-runs, instead of leaving a stale
message
Enforce that all external PRs reference an approved issue via GitHub
auto-close keywords (`Fixes #NNN`, `Closes #NNN`, `Resolves #NNN`). This
replaces the previous AI-disclaimer policy in the PR template with a
stricter requirement: external contributors must link to a
maintainer-approved issue before their PR can merge.
## Changes
- Add `require_issue_link.yml` workflow that chains off the `external`
label applied by `tag-external-contributions.yml` — listens for
`labeled`, `edited`, and `reopened` events to avoid duplicating the org
membership API call
- Scan PR body with a case-insensitive regex matching all conjugations
of `close/fix/resolve` + `#NNN`; fail the check and post a deduplicated
comment (via `<!-- require-issue-link -->` HTML marker) when no link is
found
- Apply a `missing-issue-link` label on failure, remove it on pass —
enables bulk cleanup via label filter
- Add `workflow_dispatch` backfill job to `pr_size_labeler.yml` for
retroactively applying size labels to open PRs
- Quote `author` in GitHub search queries in
`tag-external-contributions.yml` to prevent mismatches on usernames with
special characters
- Update `PULL_REQUEST_TEMPLATE.md` to replace the AI-disclaimer
guideline with the new issue-link requirement
> [!NOTE]
> `require_issue_link.yml` depends on `tag-external-contributions.yml`
running first to apply the `external` label. Deploy as a non-required
check initially, then promote to required after validation.
