fix(css): await sass/less/styl worker disposal on teardown (fix #22274)#22275
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bluwy merged 2 commits intoMay 12, 2026
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The cssPlugin buildEnd hook and the scss/less/styl processor close methods were synchronous but invoked the asynchronous worker.stop() without awaiting it. server.close() could therefore resolve before the preprocessor workers had actually shut down, leaving their ChildProcess handles alive on the event loop. Make close async end-to-end, dispose the three processors in parallel via Promise.all in createPreprocessorWorkerController, and await the controller from buildEnd.
Address review feedback: only the scss processor's close() actually needs to be async (it awaits compiler.dispose()); less and styl use real artichokie WorkerWithFallback whose stop() is sync. - Widen StylePreprocessor.close to () => void | Promise<void> matching the pattern used elsewhere in the repo - Revert lessProcessor.close and stylProcessor.close to sync - scssProcessor.close stays async (load-bearing) - preprocessorWorkerController.close still awaits Promise.all, which transparently handles the mixed void / Promise<void> returns Also drop unnecessary `port: 0` from the regression test.
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Description
cssPlugin.buildEnd()andscssProcessor.close()were synchronous but dropped an asyncworker?.stop()promise. On the scss path, that promise awaitscompiler.dispose(), which sends the IPC shutdown to the sass-embedded Dart subprocess — soserver.close()could resolve while the Dart worker was still running, leaving itsChildProcesshandle alive on the event loop.In long-lived processes the event loop eventually reaps the workers. In processes that expect to exit after
server.close()— scripts, programmatic use, Vitest global teardown — the orphanedChildProcesskeeps Node alive.See #22274 for the minimal standalone reproduction and
exitCodebefore/after. Different code path from #18224 (file watchers) but the same user-visible symptom.Changes
cssPlugin.buildEnd: sync →async, awaitspreprocessorWorkerController?.close()scssProcessor.close: sync →async, awaitsworker?.stop()— the only path wherestop()is actually async, sincemakeScssWorkerreturns a hand-rolled object whosestop()awaitscompiler.dispose()createPreprocessorWorkerControllerfan-outclose: sync →async, disposes the three processors in parallel viaPromise.allStylePreprocessor<Options>.closetype:() => void→() => void | Promise<void>(matches the convention used elsewhere in the repo)lessProcessor.closeandstylProcessor.closeare unchanged — they go through realartichokieWorkerWithFallbackwhosestop()is synchronous, so awaiting would be a no-op.On the teardown path,
server.close()now waits for scss'scompiler.dispose()to actually complete before resolving.Tests
New regression test:
packages/vite/src/node/__tests__/plugins/cssPreprocessorTeardown.spec.ts. Starts a dev server, triggers scss transform, asserts no running sassChildProcessafterawait server.close(). Fails onmainwithout this change (expected 1 to be +0).pnpm --filter vite exec vitest run src/node/__tests__/plugins/cssPreprocessorTeardown.spec.tsFixes #22274
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claude-opus-4-7-thinking-xhighto file the PR.