A source file carries one istanbul statement map per Vite environment, so a
node suite and a jsdom suite that load the same module enter the merged
report through two maps that spell one statement differently. istanbul
reconciles those overlapping ranges by attributing the hits of the narrowest
containing range, but only while a location carries numeric line and column
values. ast-v8-to-istanbul ends a whole-line statement at column Infinity, and
the partition blob serializes Infinity as null, so the merge command kept the
client-only spelling as an extra, unhit statement: a file whose every statement
ran reported 96.96% and failed the per-file 100% gate.
The coordinator now passes each partition a reporter whose onCoverage hook
rewrites every non-finite end column to a finite line-end column before the
blob is written, which restores that reconciliation without weakening the
gate. The uncovered-locations reporter reads the same column as a line end.
The Windows coverage lane grants DSH_COVERAGE_TEST_TIMEOUT_MS=90000, but two
paths declined it.
scripts/install-lefthook.spec.ts took a describe-level 30_000, restated as a
per-case constant on five cases. Every case drives spawned Git and Node
subprocesses; the slowest costs 7.5 s on an idle host, so the ceiling carried
roughly fourfold headroom and fired on branches that did not touch the file.
The suite takes 90_000 and the redundant constant is removed.
coverageTestTimeoutArgs raised --testTimeout and --expect.poll.timeout but left
--hookTimeout at Vitest's separate 10 s default, which removeFixtureSafely's
documented 10-second Windows retry window meets exactly. Raising only the test
budget would move a contended suite's failure into its teardown.
Replace Vitest's hash-based --shard with a coordinator-side
longest-processing-time assignment. The coordinator collects the
instrumented inventory from a vitest list run (dropping the exempt
heavy suites that list does not exclude), reads per-file durations from
the Vitest results cache, and seeds heavy subprocess-bound suites into
different partitions. A weight-aware test fails when assignment ignores
recorded weights, verified by injecting a file-count-only rule.
Windows coverage measured partition spread of 442s (275-717s) under
hash sharding; a simulation with the same file durations and the new
assignment balances partitions to within 21s, cutting the critical
partition to roughly half.
Tianyi Cui