Two CI failures landed after PR #196 (esp32-gpio-matrix-cb-callback)
merged. Both are independent and fixed here together.
1) **Backend E2E: ESP32 hangs at bootloader handoff.**
PR #196 added picsimlab_gpio_matrix_cb which fires on QEMU's
iothread. The handler did `_emit({...})` for every routing
change — and the ESP-IDF bootloader writes to gpio_out_sel
*hundreds* of times during early boot (each peripheral init
configures its matrix slot). Each emit acquires _stdout_lock
and writes to the worker→manager pipe. If the manager drains
even briefly slow, the pipe fills, write blocks, and the
iothread stalls — symptom: ESP32 reports `entry 0x400805e4`
then no Arduino setup() output for 75 s.
Fix: the iothread callback now ONLY mutates the SignalRouter
snapshot. It never emits. The 10 Hz poll thread
(_refresh_signal_routing) stays as the sole emitter, so the
wire-format event stream is unchanged. Benefit of having the
callback over poll-only is reduced worst-case routing-emit
latency (next poll tick vs up to 100 ms) and a warmer
snapshot dict for cheaper poll diffs.
2) **Frontend Tests: Node OOM at end of suite.**
117 test files run in one forks-pool worker. Several lazy-load
the ngspice emscripten module (~30 MB), the MixedModeScheduler
singleton, and other heavy modules whose dispose hooks aren't
reached because singletons leak across files. Cumulative heap
pressure exceeds Node's 4 GB default; the worker hits "Ineffective
mark-compacts near heap limit" AFTER all 1881 tests pass and
the OOM kill is reported by vitest as "Worker exited unexpectedly
/ Timeout terminating forks worker". This is not a real test
failure — every individual test passes.
Quick fix: pass NODE_OPTIONS=--max-old-space-size=8192 to the
`npm test` step. Long-term, the singletons should add dispose
hooks that test fixtures call in afterAll(), or the suite
should shard into multiple `vitest run --shard` invocations.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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