Files
sx/examples/concurrency/1819-concurrency-fiber-double-wait.sx
agra aae7d72a66 refactor: retire bespoke Task async; one stack behind context.io (Phase 5)
Converge the Io unification (PLAN-IO-UNIFY Phase 5). The bespoke fiber-task layer
in sched.sx — Task / TaskState / TaskErr / go / wait / cancel(Task), plus
Scheduler.task_allocs and its deinit bookkeeping (~130 lines) — is removed. There
is now ONE async stack: context.io.async / await / cancel / race / sleep over the
Io protocol, with the Scheduler as the fiber Io's engine + driver (spawn /
yield_now / suspend_self / wake / run / block_on_fd remain as the raw primitives;
race stays in sched.sx because it needs meta.sx's make_enum/make_variant).

Migrated the four go/wait users to context.io:
- 1813 — interleave + cancel (sequence 1 2 3 42 100 -99)
- 1817 — m1 end-to-end (completion in deadline order, sum 123)
- 1819 — double-AWAIT loud-abort via the Future one-awaiter guard
- 1820 — deinit: dropped the go/task_allocs tasks; now exercises timers/io_waiters/
  kq cleanup (freed=2, live=3 = the documented per-spawn closure-env residual)

Updated readme.md (the user-facing async section documents context.io.async /
await / race / sleep) and the stale sched.go/sched.Task comments in io.sx.

Suite 854/0; no .ir churn (Task removal touched no snapshotted IR); migrated
examples byte-identical on aarch64-macOS + aarch64-linux. PLAN-IO-UNIFY Phases 0-5
all complete — the two parallel async stacks are now one, behind context.io.
2026-06-28 10:14:17 +03:00

23 lines
1.1 KiB
Plaintext

// A `Future` allows ONE awaiter — a second concurrent `await` on the same pending
// future would overwrite the single `park` slot, and completion would wake only
// the second, stranding the first forever. Regression (B1.4a review, P1-c): the
// guard aborts loudly instead of silently deadlocking. Now over the unified
// `context.io` async layer (PLAN-IO-UNIFY Phase 5 — the bespoke `Task`/`wait` is
// retired).
//
// aborts (exit 134) after the diagnostic — aarch64-macOS-pinned.
#import "modules/std.sx";
sched :: #import "modules/std/sched.sx";
S :: struct { t: *Future(i64); }
main :: () -> i64 {
st : S = ---; st.t = null;
s := sched.Scheduler.init(); ps := @s; pst := @st;
mkprod :: (ps: *sched.Scheduler, pst: *S) { pst.t = context.io.async(() -> (i64, !) => { ps.yield_now(); 42 }); }
mkw :: (ps: *sched.Scheduler, pst: *S) { ps.spawn(() => { x := pst.t.await() or { -1 }; print("got {}\n", x); }); }
push .{ io = xx s } {
mkprod(ps, pst); mkw(ps, pst); mkw(ps, pst); // second waiter → loud abort
s.run();
}
return 0;
}