---
model: openai/gpt-5.6-sol
service: opencode
session: 76c5d31c-5a2f-4503-9b16-410ee7f4fab3
timestamp: 2026-08-21T02:35:37Z
git_ref: ae6f2ac3
scope: code
substantive: true
raw_file: 20260821T023537Z_ae6f2ac3_prompt_io.raw.md
---

## Prompt

Simplify bounded actor cancellation by passing an explicit absolute
deadline from `Portal.cancel_actor()` through `_run_from_ns()`,
`Actor.start_remote_task()`, and `Channel.send()` into
`MsgpackTransport.send()`. Avoid a `ContextVar`, watcher tasks, shared
status, coalescing, and waiter state. After tracing the current
`Start -> StartAck -> CancelAck` transaction, rename the local result to
`cancel_ack_received`, document its exact semantics, and link a focused
follow-up for a dedicated `Cancel -> CancelAck` protocol.

## Response summary

Threaded one absolute Trio deadline through the existing private
actor-cancel RPC path. The transport retains complete-frame shielding
for ordinary sends, while a cancel-control send that overruns its
deadline force-closes the potentially corrupted stream before releasing
the send lock. The outer actor-cancel scope uses the same deadline for
ack waiting and redelivers pending caller cancellation afterward.

Renamed the completion flag to `cancel_ack_received` and documented that
the current private call consumes `StartAck`, then receives a real
`CancelAck` after `Actor.cancel()` completes; this does not establish
that the OS process exited. Added a source TODO linking issue #506 for
the future first-class `Cancel -> CancelAck` transaction.

Focused transport and actor-cancel verification passed all four tests.

## Files changed

- `tractor/runtime/_portal.py` - own the absolute deadline, accurately
  record ack receipt, and link the dedicated cancellation protocol.
- `tractor/runtime/_runtime.py` - forward the optional deadline for the
  exact private `Start` publication.
- `tractor/ipc/_chan.py` - pass the operation-specific deadline to the
  transport without changing ordinary sends.
- `tractor/ipc/_transport.py` - bound the shielded frame publication and
  close a partial-frame stream before unlocking it.
- `tests/ipc/test_each_tpt.py` - cover deadline expiry after a partial
  frame prefix reaches the stream.
- `tests/test_to_actor.py` - prove actor-cancel publication and ack
  waiting share one absolute timeout budget.

## Human edits

The human rejected the initial watcher-task, shared `_SendStatus`, cancel
coalescing, and per-waiter design as unnecessary complexity. They also
rejected `ContextVar` propagation in favor of explicit functional
threading, selected a single absolute deadline for publication and ack
waiting, and required item 2 to remain separate from the item-3 child
reaping work. After reviewing the result, they requested the precise
`cancel_ack_received` name, a detailed protocol-trace comment, a focused
follow-up issue, and a linked source TODO. No direct source-line edits
were made by the human.