---
model: gpt-5.6-sol
service: opencode
session: trio-pre-handshake-child-death
timestamp: 2026-08-28T04:51:19Z
git_ref: fb6d81d3
scope: code
substantive: true
raw_file: 20260828T045119Z_fb6d81d3_prompt_io.raw.md
---

## Prompt

The human approved the next WireGuard Layer C implementation step after
committing child-side network namespace bootstrap.

## Response summary

Restore and harden the boot-race design originally implemented by
`3b0724eba85b4014170ed95773e1e41a60d5c513` before transferring
namespace FDs. Race the initial peer handshake against child-process
death so a pre-connection bootstrap failure surfaces instead of
parking `ActorNursery.start_actor()` forever.

## Files changed

- `tractor/spawn/_spawn.py` - provide the generic handshake/process
  death race.
- `tractor/spawn/_trio.py` - use the race during Trio child startup.
- `tests/test_spawning.py` - cover handshake-first and death-first
  schedules, simultaneous outcomes, waiter errors, and backend cleanup.

## Human edits

The human approved continued Layer C implementation. The agent narrowed
the next slice to failure detection after analysis showed FD transfer
would otherwise introduce a parent hang. The human then identified the
earlier `wait_for_peer_or_proc_death()` implementation and required
explicit credit; the source docstring and commit message now cite its
original commit rather than a later cherry-pick. The human directly
reflowed `_trio.py` to the project line limit and normalized nearby
quotes. The human also required naming the race helper in its lifecycle
comment, explicit `trio.Cancelled` handling in waiter tests, expected
cancellation diagnostics, and a `trio.Process`-constrained test double.
After mainline portability verification, the human chose to commit the
fix on the current WireGuard branch and require its cherry-pick onto
`main` as a blocker in the eventual WireGuard pull request.