EOF-driven cancellation can be absorbed by the ctx nursery before
teardown sees a disconnected channel and skips its recorded error.
Route an unfinished transport fault through `wait_for_result()` so
it raises the original error without waiting on broken IPC or
manufacturing a cancellation requester.
Share `ContextStatus._outcome_is_unfinished()` between EOF
notification and ctx teardown. Both buffered `Return` msgs and
decoded falsey results remain completed outcomes; notification
requires no existing error while teardown raises the recorded one.
Deats,
- Reconcile the close example and advanced-fault matrix with prompt
fault propagation, preserving break order and pre-`Stop` cases.
- Check exception leaves, socket causes, cancellation provenance,
and post-close send/receive error precedence and identity. Keep
synthetic Ctrl-C for the healthy no-break cases.
- Cover buffered/consumed `None`, `False`, `0`, and empty-string
results across EOF, including final value and type preservation.
- Add `assert_child_reaped()` for retained process handles. Check
both backend completion and PID disappearance without cleanup.
(this patch was generated in some part by `opencode` using
`gpt-6-astra` (`openai`))