feat(tasks): task_detach — fire-and-forget tasks reap their handle slot (#530)#532
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…ot (#530) Finished tasks were never removed from the 255-slot handle table, so task_spawn failed after 255 spawns per process — a LIFETIME cap even when every task was joined. task_detach of id (pthread-detach precedent) marks a task nobody will join: reaped at finish, at immediate-detach of an already-finished task, and at task_kill. An uncaught death still prints and still fails the process (#493 — the flag survives the reap in a scheduler-level counter). A task may detach itself via task_self. Also fixes ready-queue poisoning surfaced by the same workload: a task killed while READY left a stale entry; enough of them filled the fixed 256-slot queue, whose push then silently dropped real wakeups — a spurious deadlock. task_kill now removes the victim's pending entry. Surfaced by the #523 liferaft migration (deliverer task per in-flight message; crash teardown kills pending deliverers in bulk). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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Closes #530
What
task_detach of id→ 1 (0 for main/unknown). Marks a task fire-and-forget (the pthread-detach precedent): it is reaped —task_free+ handle-slot release — the moment it finishes, immediately if already finished, and attask_kill. A reaped id reads as unknown afterwards (task_joinnull,task_alive0). A task may detach itself viatask_self.Why
Finished tasks were never removed from the 255-slot handle table before process exit, so
task_spawnfailed withEK_LIMITafter 255 spawns per process lifetime — even when every task was joined (minimal repro in #530). The cap now bounds concurrent tasks, as its message always claimed.Also fixed: ready-queue poisoning (found by the new tests)
A task killed while READY left its stale entry in the fixed 256-slot ready queue; the trampoline skips stale ids, but enough of them fill the queue, whose push then silently drops real wakeups — a spurious
deadlock.task_killnow removes the victim's pending entry (sched_ready_remove). liferaft's crash teardown kills pending deliverers in bulk, so this was load-bearing for the same workload.#493 guarantee preserved
A detached task's uncaught death still prints its trace and still fails the process at exit: the
err_unobservedflag moves to a scheduler-level counter before the slot frees. New exit-contract casetask_exit_detached_death.eigs(rc 1) pins it.Tests
tests/test_tasks.eigs(+8, 77/77): 300 detached spawns (impossible pre-fix), detach-of-finished reaps immediately, join/alive of a reaped id, 300 detach+kill cycles (deadlocked pre-queue-fix), self-detach viatask_self, main/unknown refused. Plus the exit-contract case above.Docs: BUILTINS.md row, SPEC.md Cooperative tasks paragraph, CHANGELOG. Discoverability gate green (213 builtins).
Validation
detect_leaks=1(rebased on main): 2704/2704, leak tally 0Unblocks #523 (liferaft chaos runs spawn tens of thousands of short-lived deliverer tasks).
🤖 Generated with Claude Code