A cancelled async worker now abandons its body at its next suspend instead
of running to completion.
- Cancel-flag back-ref (D4): SpawnOpts.cancel_flag (core.sx) + Fiber.cancel_flag
(sched.sx), set from opts.cancel_flag in Scheduler.spawn_raw; async passes
xx @f.canceled (the Future.canceled Atomic(bool) erased to *void).
- Delivery: Scheduler.suspend_raw consults fiber_canceled(self.current) PRE-park
(raise without parking — no deadlock if cancel landed before the worker ran)
and POST-resume (cancel landed while parked), raising error.Canceled.
cancel(f) flips the sticky flag, marks .canceled, and wakes the worker.
- async worker is failable Closure() -> ($R, !); the completion closure
f.value = worker() catch {…} marks .canceled/.failed and wakes the awaiter,
so post-suspend side effects never run. New failable io.sleep(ms) is the
cancellation point.
- Compiler: a -> ! fn whose only error source is try-ing a protocol method
(io.suspend_raw) was wrongly flagged 'declared ! but never errors';
collectErrorSites now marks a try of a non-identifier callee as a dynamic
(opaque) error source, suppressing the warning.
- Two UAFs found by adversarial review and fixed: (1) cancel-before-park
orphaned io.sleep's armed timer — suspend_raw's pre-park raise now evicts the
current fiber's timer/waiter first; (2) cancel(f) could wake a reaped worker —
now only wakes when was_pending.
Migrated 1805/1806/1824 to failable workers. Lock: example 1825 (seq: 1 -99,
post-suspend line never runs); byte-identical on aarch64-macOS + aarch64-linux.
.ir churn is the SpawnOpts layout change (type-table string renumbering).
`context.io.async(worker)` / `await` now run over the `Io` PROTOCOL, so the
same code interleaves under the fiber scheduler or runs inline under the
blocking `CBlockingIo` — one async stack, reached purely through `context.io`.
- Protocol: `suspend_raw(park: *ParkToken)` (was by-value). A suspending impl
records the parked execution context into `park.handle` before parking, so a
cross-context `ready(park)` knows whom to resume; `Scheduler.suspend_raw`
writes `self.current`, `CBlockingIo` ignores it.
- io.sx async layer rewritten colorblind: `async` submits the worker through
`io.spawn_raw` (inline under blocking, a fiber under the scheduler) and returns
a HEAP `*Future($R)` the worker fills later; `await` suspends via `suspend_raw`
until ready, then returns/raises. The generic worker is bridged to spawn_raw's
raw `(*void)->void` entry via a monomorphic `ThunkBox` (a heap-boxed nullary
completion closure) — all genericity lives in the closure env. Workers are
nullary (inputs captured at the call site) because a variadic pack can't cross
the fiber boundary. `CBlockingIo.spawn_raw` now runs the worker inline.
- Migrated 1805/1806 to the nullary `*Future` form; retrofit 1822/1823 to the
`push .{ … }` partial-context literal (inherits allocator/data).
- The async machinery adds a few prelude types, shifting the type-name table —
40 `.ir` snapshots regenerated (no behavior change; only `.exit`/`.stdout`/
`.stderr` would signal that, and none changed).
Locked by examples/concurrency/1824 — two async tasks under the fiber Io, the
completion log proving deferral (1 2 then 10 20 then 123). Suite 829/0,
byte-identical aarch64-macOS host + aarch64-linux container.
Move examples/*.sx and their expected/ snapshots into per-category
subfolders (examples/<category>/...). Folder = leading filename token,
with ffi-objc/ffi-jni kept whole; filenames are unchanged. The corpus
runner and LSP sweep now discover each category's expected/ dir, while
issues/ stays flat. Example 1058's repo-root-relative companion import
is made file-relative. Path strings embedded in 164 snapshots were
regenerated (path-only changes). Test-layout docs in CLAUDE.md updated.
