ci-prepare-test-scope.cjs's empty-detection FALLBACK hardcoded
tests/core.test.cjs, deleted in #1291. Every scoped lane (scope=targeted|
windows) that hit the fallback wrote the stale path into .ci-selected-tests.txt
and crashed run-tests with "requested test file(s) not found: core.test.cjs".
The full/sharded lanes glob the suite and were immune, so only the scoped
lanes went red (e.g. run 27599149212 on #1308).
Existence-filter the FALLBACK at write time and fall back to the 'unit' suite
sentinel (the #408/#641 path, resolved live by run-tests) when nothing
survives, so a stale reference degrades instead of crashing the lane. Detected
lists still pass through verbatim (they may carry a suite sentinel and are
already filtered by affected-tests-lib). Refactor to an exported, testable
resolveSelection().
Add a generative parity guard (DEFECT.GENERATIVE-FIX) asserting every FALLBACK
entry resolves on disk or is a known suite sentinel — it fails the instant a
refactor deletes a listed file, which #1291 did and CI did not catch — plus
resolveSelection unit tests and an end-to-end subprocess test.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>