Only P0 preempts in-progress runs (emergency reservation). P1-P9 no longer
cancel lower-priority runs; instead traffic-control holds back (bounded poll,
kept under timeout-minutes) while strictly-higher-priority PRs still have
active/queued CI runs, so their heavy jobs reach the runner queue first.
New `broken` label forces effective priority below P9 (sentinel 10): a broken
PR never preempts (even if also labelled P0 -- broken wins) and always yields,
and because its run is wasted, ANY higher-priority PR (not just P0) may cancel
its in-progress run to reclaim the runner. Net rule: a strictly-lower run is
cancelled iff (self is P0) OR (target is broken); otherwise yield.
All existing safety preserved: never main/push runs, never our own run, never
an equal-or-higher-priority PR; PR-controlled strings via env/jq only;
continue-on-error + set +e + always exit 0; traffic-control stays a
non-required best-effort job and ci-passed is unchanged.
Validated with actionlint and a mocked-gh + fake-clock logic harness.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
JMR-devandClaude Opus 4.8
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