close-draft-prs.yml (on pull_request_target after #760) cannot close fork draft
PRs whose head branch name looks like a Git SHA — GitHub never dispatches
pull_request_target for such branches, and a pull_request run from a fork gets a
read-only token. So a draft PR on a SHA-named fork branch evades the auto-close.
Add close-draft-prs-sweep.yml: a schedule (every 6h) + workflow_dispatch sweep
running in base-repo context with pull-requests: write that paginates open PRs,
filters to non-OWNER/MEMBER/COLLABORATOR drafts, and closes + comments them with
the identical policy/message as the event-driven workflow. Re-fetches each
candidate before mutating (TOCTOU guard), closes before commenting so
enforcement is never gated on the explanatory comment, and core.setFailed on
partial failures. The per-PR workflow remains the fast path; this is the
safety net for the documented residual bypass.
Extends tests/workflow-maintainer-skip.test.cjs with structural guards locking
the triggers, write permission, maintainer carve-out, pagination, and message.
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
Bare `pull_request` hands fork PRs a read-only GITHUB_TOKEN, so the
close/comment API calls 403 and a first-time/external contributor's draft
PR survives — bypassing the auto-close for exactly the population the job
targets. Switch to `pull_request_target`, which runs in the base-repo
context with a write-capable token even for fork PRs. Safe because the job
never checks out or executes PR-supplied code; it only reads event metadata
and calls the GitHub API. The minimal `permissions: pull-requests: write`
block still constrains the token.
Add a regression guard in tests/workflow-maintainer-skip.test.cjs asserting
the workflow triggers on pull_request_target and not bare pull_request.
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
