The fourth CI run failed broadly: ~15 timing-sensitive tests (throttle, flush,
resize clear-counts, rapid-input ordering) failed under sequence.concurrent on
the 4-core ubuntu runner. These assert render/commit counts driven by the
~32ms commit throttle; in-file concurrency starves them of wall-clock when many
share few cores. It passed locally only because dev machines have more cores —
the classic "works on my 12-core mac" trap.
Remove sequence.concurrent from both the main and PTY configs; keep
fileParallelism (pool: forks), which is the proven, stable win (PTY suite still
~3x faster than serial). The it.sequential/describe.sequential markers and
context-local expect become harmless no-ops under serial in-file execution.
Verified cold (no dist): vp run ci exits 0, 0 lint warnings, all tests pass.
With resize rendering now synchronous, no PTY test depends on wall-clock
timing, so concurrent execution is safe. Enable sequence.concurrent: true.
Each test already spawns its own isolated PTY subprocess (or in-process app)
with no shared state.
Verified stable: 12/12 runs green under sequence.concurrent with forks capped
to 4 (mimicking a 4-core CI runner) — the configuration that reliably flaked
before the resize fix. No it.sequential opt-outs are needed.
The PTY suite was the CI wall-clock bottleneck, run serially via
fileParallelism:false. The original reason for serializing was a node-pty
constraint — it needs child_process.fork(), not worker_threads — but that only
dictates the pool TYPE, not single-file execution. Each test already spawns its
own isolated PTY subprocess (helpers/term.ts, run.ts: no shared ports, temp
files, or mutable globals; cwd is the read-only fixtures dir), so files
parallelize safely.
Set pool:"forks" explicitly (the real node-pty requirement) and
fileParallelism:true. Measured: the PTY suite drops ~37s -> ~13s (~3x), and the
full `vp run ci` graph drops ~41s -> ~20s cold (no task cache, no prebuilt
dist). Verified stable across 9 isolated PTY runs (incl. maxForks capped to 4
to mimic a 4-core CI runner) and 3 cold full-graph runs — 110 PTY tests pass
every time, zero flakes. testTimeout stays 15s (slowest test ~2s) to absorb CPU
contention on smaller runners.
node-pty 1.1.0's POSIX_SPAWN_CLOEXEC_DEFAULT flag fails on macOS 26 (Tahoe).
Beta.13 fixes this. Rewrote helpers to match Ink's node-pty architecture,
removed python pty-spawn and force-tty workarounds, added check-pty guard
that skips all 82 tests when node-pty is unavailable.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Yunfei He