fix(node/ext): make zlib write callback async to match node behavior#32130
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fraidev merged 1 commit intodenoland:mainfrom Feb 12, 2026
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Deno's zlib `Zlib::write` was calling `processCallback` synchronously, while Node.js runs compression on the libuv threadpool and calls it asynchronously. This caused several issues: - destroy() couldn't propagate before subsequent write callbacks fired - stream buffering didn't work correctly (needDrain was never set) - flush operations didn't produce separate compressed chunks This change removes the synchronous callback from Rust's `Zlib::write` and schedules `processCallback` via `process.nextTick` from JavaScript. A `_callbackPending` flag ensures backward compatibility with Brotli/Zstd handles which still call the callback synchronously. Enables 3 node_compat tests: - test-zlib-destroy-pipe - test-zlib-flush-drain - test-zlib-flush-write-sync-interleaved
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Deno's zlib
Zlib::writewas callingprocessCallbacksynchronously, while Node.js runs compression on the libuv threadpool and calls it asynchronously. This caused several issues:This change removes the synchronous callback from Rust's
Zlib::writeand schedulesprocessCallbackviaprocess.nextTickfrom JavaScript. A_callbackPendingflag ensures backward compatibility with Brotli/Zstd handles which still call the callback synchronously.Enables 3 node_compat tests: