Fix Node.js exit for library builds with pthreads#26441
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brendandahl wants to merge 1 commit intoemscripten-core:mainfrom
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Fix Node.js exit for library builds with pthreads#26441brendandahl wants to merge 1 commit intoemscripten-core:mainfrom
brendandahl wants to merge 1 commit intoemscripten-core:mainfrom
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kleisauke
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Mar 12, 2026
sbc100
reviewed
Mar 12, 2026
When building without a main function (a library build), and using pthreads to do background work, the main Node.js thread has no event loop work to keep Node.js alive. The workers are also unreferenced when they start executing, so Node.js will exit prematurely before the background thread can finish its work. To prevent this, change the worker reference logic so that we only `unref()` workers upon execution if `HAS_MAIN` is enabled. For library builds, we keep them referenced (`worker.ref()`) to keep the process alive while they are active. We also ensure idle workers returned to the pool are `unref()`'d across all Node builds (not just with `PROXY_TO_PTHREAD`) so that an idle pool doesn't leak references preventing exit. Fixes emscripten-core#23092
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When building without a main function (a library build), and using pthreads to do background work, the main Node.js thread has no event loop work to keep Node.js alive. The workers are also unreferenced when they start executing, so Node.js will exit prematurely before the background thread can finish its work.
To prevent this, change the worker reference logic so that we only
unref()workers upon execution ifHAS_MAINis enabled. For library builds, we keep them referenced (worker.ref()) to keep the process alive while they are active.We also ensure idle workers returned to the pool are
unref()'d across all Node builds (not just withPROXY_TO_PTHREAD) so that an idle pool doesn't leak references preventing exit.Fixes #23092