v0.1.1: threading wait(timeout) deadlock fix#268
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Pre-v0.1.1, every threading.Condition.wait(timeout=...), Event.wait(timeout), and Semaphore.acquire(timeout) call hung on sync.Cond.Wait, which has no timeout. The Go deadlock detector killed the process with "all goroutines are asleep - deadlock!". This release replaces sync.Cond with chCond, a channel-backed notifier. Each Wait() registers a fresh channel; the FIFO of waiters is woken by Notify(n) or Broadcast(); timeout via select + time.After. What's wired: - Event.wait(timeout=None) - Condition.wait(timeout=None) — returns True if notified, False on timeout - Condition.wait_for(predicate, timeout=None) — returns last predicate result - Condition.notify(n) — wakes up to n waiters (was always Signal-one) - Semaphore.acquire(blocking, timeout) - Barrier.wait(timeout) — on timeout, breaks the barrier threading.BrokenBarrierError (subclass of RuntimeError) is now exposed as a real class on the threading module instead of a bare RuntimeError with a "BrokenBarrierError" message. First release of the v0.1.x cycle. Spec at notes/Spec/1500/1542_goipy_v0101_condition_timeout.md; fixture 347 covers all four primitives across timeout-expired and notified-before-timeout paths. Closes V1 from notes/Spec/1500/1541_goipy_v01x_roadmap.md.
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Summary
sync.CondwithchCond(channel-backed notifier with timeout) insidevm/stdlib_threading.go. Pre-v0.1.1Condition.wait(timeout=…),Event.wait(timeout=…),Semaphore.acquire(timeout=…),Barrier.wait(timeout=…)hung onsync.Cond.Waitand tripped Go's deadlock detector.timeoutthrough every primitive that takes one;Condition.notify(n)now wakes up to n waiters instead of always Signal-one.threading.BrokenBarrierErroras a real subclass ofRuntimeErroron the threading module.First release of the v0.1.x cycle (roadmap at
notes/Spec/1500/1541_goipy_v01x_roadmap.md, V1). Spec atnotes/Spec/1500/1542_goipy_v0101_condition_timeout.md.Test plan
go build ./...go test ./vm/ -run TestFixtures— all 347 fixtures pass/tmp/probe_v01x_thr2.pyno longer deadlocks;Condition.wait(timeout=0.05)returns False after ~50ms as expected