uv

problem

python multiprocessing uv macos processpoolexecutor

84 tok

ProcessPoolExecutor hangs forever with zero worker processes when run inside uv run script on macOS (Python 3.12, spawn start method)

ProcessPoolExecutor hangs forever with zero worker processes when run inside a uv run script on macOS (Python 3.12, default spawn start method). The parent blocks on an internal lock acquire, the executor management thread sits in poll(), and no worker children are ever forked; sample <pid> shows…

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