Bind coverage repair to the stable PR head and merge identity plus protected-main containment without treating the live base SHA projection as permanent identity.
Add semantic regression coverage for base advancement and update the governance documentation.
The Coverage context was the PR critical path (~17 min end to end):
coverage-current re-ran the whole suite serially (-p 1, ~13 min) and
coverage-baseline re-ran it again at the merge-base (~13 min) although
that profile is a pure function of the base commit.
- coverage-current now owns only the scoped (standard-tier) profile;
full-suite candidate profiles come from a 5-way shard matrix
(app/cli/generators/helpers/remaining) that keeps -p 1 inside each
shard on isolated runners. scripts/ci/test-packages.sh list-coverage
defines the shards and verify proves the union equals the previous
single-run package set exactly once.
- the aggregate Coverage job reassembles the disjoint shard profiles
into coverage.txt before make coverage-gate, failing closed when a
shard file is missing, so gate semantics (100% changed-code +
scope-matched overall non-regression) are byte-compatible.
- coverage-baseline restores the merge-base full-suite profile from an
exact-key cache (merge-base SHA + resolved Go version) written by the
last green main push; any miss falls back to recomputing in the
merge-base worktree. Exact key only - no prefix fallback, a near-miss
profile would compare the candidate against the wrong commit.
- new contract tests pin the shard matrix, the assembly step, the
exact-key cache pair, and the absence of restore-keys; the package
plan test also covers the coverage shard partition.
chichuan