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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Backport libuv 1.53.0 (Windows AppContainer named-pipe fix) to v24.x","articleBody":"### Problem\n\nInside a Windows AppContainer, `child_process.spawn` with `stdio: 'pipe'` or `'ipc'` never completes and spins one core.\n\nlibuv 1.52.1, which v24.x and v26.x bundle, names child stdio and IPC pipes `\\\\?\\pipe\\uv\\\u003cn>-\u003cpid>` (`uv__unique_pipe_name`, `deps/uv/src/win/pipe.c`). Inside an AppContainer, CreateNamedPipe is refused with `ERROR_ACCESS_DENIED` except under `\\\\.\\pipe\\LOCAL\\`. `uv__pipe_server` reads `ERROR_ACCESS_DENIED` as a name collision, increments the counter and retries, so the loop never ends.\n\nlibuv fixed this in 1.53.0 (libuv/libuv#5178, fix libuv/libuv#5181, commit 2cadaa401670): it adds `LOCAL\\` only when the process token reports `TokenIsAppContainer`. Behaviour outside an AppContainer is unchanged. #66282 (\"deps: update libuv to 1.53.0\") is open against main.\n\n### Minimal reproduction\n\nRun node v24.x inside an AppContainer (for example with the `test/appcontainer.c` helper added in libuv/libuv#5181), with read access to node's directory:\n\n```js\nconst { spawn } = require('node:child_process');\nspawn(process.execPath, ['-e', '0'], { stdio: 'pipe' })\n  .on('exit', (code) => console.log('exit', code));\n```\n\nObserved (our Windows testing, 27 and 28 September 2026): nothing is printed and the process spins one core. The same happens with an `'ipc'` stdio entry.\n\n### Expected behaviour\n\n`exit 0`.\n\n### Proposed fix\n\nLand libuv 1.53.0 on v24.x (and v26.x) once #66282 lands on main. If a libuv minor update is not acceptable for an LTS line, float 2cadaa401670 on `deps/uv` instead. Its runtime change is confined to `src/win/pipe.c` (the rest is tests and CI), and that hunk applies cleanly to v24.x's `deps/uv/src/win/pipe.c` today (`git apply --check`; v26.x's file is identical).\n\n### Why it matters\n\nAppContainer is the Windows sandbox for running agent-driven or untrusted code. Without the fix, any node program that spawns a child with pipes (package managers, CLIs, process supervisors) hangs at 100% CPU instead of failing, which is hard to diagnose. v24.x is the line applications pin to.\n","author":{"url":"https://github.com/jonathanlindsay","@type":"Person","name":"jonathanlindsay"},"datePublished":"2026-09-28T08:25:16Z","url":"https://github.com/nodejs/node/issues/66374"}