Lean 4 fork for HoTT-compatible kernel extensions (Path types, transport, HITs). Maintained against upstream leanprover/lean4.
5d41b3bdce
This PR avoids a potential deadlock on shutdown of a Lean program when the number of pooled threads has temporarily been pushed above the limit. There's a potential race between the finalizer "waking up everyone" after setting `m_shutting_down = true` and a worker that is about to be throttled because of concurrency limits. - `m_max_std_workers = 1`, `m_std_workers.size() = 2`, and the queue still has tasks. - Finalizer sets `m_shutting_down = true` and calls `notify_all()` while a worker is running a task (outside of the mutex). - Worker finishes a task, re-enters the loop, sees work, and "should wait" because `active >= max`. - Worker then calls `wait()` after the notify and never wakes, so `join()` in the finalizer hangs. This PR avoids the worker being blocked by not `wait()`ing if we are already shutting down. The code is restructured a bit for readability, where the first section is "there's no work in the queue" and the next section is "there is some work in the queue" |
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| CONTRIBUTING.md | ||
| flake.lock | ||
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| lean-toolchain | ||
| lean.code-workspace | ||
| LICENSE | ||
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| RELEASES.md | ||
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