Investigation scaffolding for the Chrome-only KiCad coroutine renderer crash.
Adds isolated reproduction probes exercising the coroutine/Asyncify/fiber layer
under KiCad-like conditions, runnable in BOTH Firefox and system Chrome.
- tests/playwright-coroutine.config.ts + test:coroutine:firefox|chrome npm
scripts: run the coroutine specs in Firefox AND system Chrome (the old e2e
config only used bundled Chromium, which never reproduced the crash).
- tests/apps/standalone/coroutine-pthread/: no-wx + pthreads reproduction probes
(fiber-in-main, nested invoke_/dynCall boundaries, RunMainStack, embind,
main-loop/rAF activation) + worker_dom_stub.js for wx+pthreads builds.
- tests/apps/Makefile.wasm: coroutine-pthread{,-main,-nested,-nested-ex,-wx,
-embind,-mainloop} targets.
- scripts/common/shims/diagnostics.js: add EM_ASYNC_JS handleSleep enter/wake
tracking (DIAG_SLEEP) to detect nested-async at the crash.
Findings (details in research notes): every isolated factor so far — direct /
nested / RunMainStack fiber, wx event loop + all 13 scenarios incl EM_ASYNC_JS,
pthreads, and main-loop/rAF activation — runs CLEAN in system Chrome. The
coroutine/Asyncify layer is exonerated; GL/WebGL is the remaining untested factor
(next). The reliable FF-pass/Chrome-fail repro is still the KiCad pcbnew e2e.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>