---
model: openai/gpt-5.6-sol
service: opencode
session: moc-teardown-completion-20260804
timestamp: 2026-08-04T03:03:09Z
git_ref: 65bf9df5
scope: code
substantive: true
raw_file: 20260804T030309Z_65bf9df5_prompt_io.raw.md
---

## Prompt

Patch Tractor's `maybe_open_context()` so the final consumer waits for
resource `__aexit__()` completion and receives cleanup errors. Reuse
`outcome.Outcome` for the exit result; use the smaller mutable
`_CtxExit` holder if that makes the implementation simpler. Add and run
the relevant existing unit tests, but do not commit or push the patch.
After reviewing the result, simplify `_CtxExit` back to an optional
exception because the success outcome carries no useful value.

## Response summary

Added an exception-backed completion handshake between
`_Cache.run_ctx()` and the final `maybe_open_context()` consumer.
Serialized consumer registration and final teardown under the per-key
lock, preserving that lock for queued entrants. Added deterministic
regressions for normal exit, cleanup errors, cancellation interactions,
service-nursery cancellation, and teardown re-entry.

## Files changed

- `tractor/trionics/_mngrs.py` - publish and unwrap cached exit outcomes.
- `tests/test_resource_cache.py` - cover completion and cancellation.

## Human edits

The user directed the final simplification from `outcome.Outcome` to an
optional exception field. The patch remains uncommitted.