Files

T

retoorandClaude Sonnet 5 9dbd1fe667 Add plexer subsystem, container test infra, and last-resort opencode box backend

- Plexer: always-active terminal multiplexing. NativePlexerController/
  TmuxPlexerController share one interface, chosen by which env var is
  already set (TAI_PLEXER_SOCKET vs TMUX_PANE); NativePlexerBackend is
  the pty.fork()-based wrapper (raw mode, SIGWINCH resize forwarding,
  a Unix-socket control protocol, continuous session logging, a
  Ctrl+A prefix key distinct from tmux's own Ctrl+B). Auto-wraps new
  interactive shells via a .bashrc hook mirroring the existing
  command-not-found install pattern, gated on $TMUX/$TAI_PLEXER_ACTIVE/
  a $HOME/.tai-no-plexer bypass. New plexer_send/read/type/status
  tools, env-gated on a detected controller.
- tests/container.py + docker-compose.yml + tests/docker/Dockerfile:
  a disposable podman/docker image for the tests that must never touch
  a real machine (installing the plexer hook into a real ~/.bashrc, a
  live tmux session). Required suite (test_seal.py, test_tai.py,
  tests/plexer.py, tests/bashrc.py) gates the result; tests/rag.py
  runs as best-effort since its real-LLM dependency can't be satisfied
  inside a disposable container with no nested engine.
- tests/bashrc.py: real end-to-end hook install + bash -i auto-wrap,
  anti-recursion, tmux-active skip, non-interactive skip, a live
  TmuxPlexerController test, and an install/uninstall round-trip.
- tests/plexer.py: NativePlexerBackend under a real pty, plus a
  dedicated robustness pass (file permissions, >64KB payload framing,
  a malformed control request, a genuine self-deadlock fix in the
  write-to-child path).
- tai_test.py: the shared async process-driving framework (pipe/pty
  transport, group-wide kill-and-reap, a StdinBridge for --interactive)
  both test files build on.
- ChatClient last-resort backend: when there's no local opencode CLI
  but the sandbox box is already running, install opencode into it
  (official Node tarball, not apt -- apt's nodejs/npm pull in
  webpack/babel/jest as transitive deps) and route through it instead
  of giving up. Only reachable after the first retry round already
  failed everything else; never creates the box itself. TmuxPlexerController.status()
  fixed to use `list-panes` instead of `display-message -p`, which
  silently fell back to the default pane instead of erroring against
  a dead target.
- Fix 4 pre-existing test_tai.py bugs surfaced by running it in a
  clean environment for the first time: two stale mock signatures
  (subprocess.run's stdout= kwarg, Chat.complete's deadline= kwarg),
  one $TMUX-dependent catalog assertion, one tty-dependent color
  assertion.
- research/: a sourced research archive (Source Dossier/Citation
  Card/Conclusion tiers) backing the above design decisions, with its
  own audit.py consistency checker.
- .gitignore: fix a blanket *.md rule that was about to silently drop
  the entire research/ archive from version control; add __pycache__/
  and the one-off debug transcript this session started from.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

2026-10-10 04:36:05 +02:00

2.7 KiB

Raw Blame History

Understanding asyncio.subprocess.Process garbage collection — discuss.python.org

Metadata

Field	Value
Institute	Molodetz Institute — Research & Retrieval Division
Subject	async-pty-process-testing
Document type	Source Dossier
Tier	1
Source title	Understanding asyncio.subprocess.Process garbage collection
Source URL	https://discuss.python.org/t/understanding-asyncio-subprocess-process-garbage-collection/105973
Source publisher / author	Python Discourse community
Source type	forum thread
Source date (published)	Unknown — not stated
Date researched	2026-10-09
Researched by	tai (agent), model: Claude Sonnet 5, on behalf of retoor
Research method	web search synthesis
Confidence	Medium
Status	Active

Summary

A Discourse thread examining what happens to a still-running asyncio.subprocess.Process object when it's garbage collected. The stdlib documentation states the child gets killed as a safety net in that case — but a forum participant reported observing output continuing to appear after the "owning" script had already finished, suggesting this safety net is not reliably instantaneous or complete in practice.

Key findings

asyncio.subprocess.Process's own documentation states that if the process object is garbage collected while the process is still running, the child process will be killed — a documented safety net, not an accident of implementation.
Despite that documented behavior, a thread participant reported a case where a subprocess's "Step" output kept appearing after the main script had already exited, implying the GC-triggered kill either didn't fire promptly or didn't fully suppress output in that instance.

Pros / strengths

A concrete counter-example to "just let Python's GC clean it up" as a cleanup strategy — directly useful as evidence against relying on implicit cleanup.

Cons / limitations / caveats

A single forum report of unexpected behavior, not a reproduced, isolated bug report with a minimal test case — the exact conditions that produced it were not independently verified in this research pass.

Relevance to tai

Reinforced the decision that tai_test.py.TestCase.execute() must explicitly call await proc.terminate() for every spawned process in its finally block, regardless of whether the test passed, failed, or was cancelled — never relying on Python's garbage collector or process-object destruction to clean anything up, consistent with the companion finding in bpo-wait-for-timeout-leaves-process-alive.md that a bare timeout alone doesn't guarantee cleanup either.

Changelog

Date	Change
2026-10-09	Initial dossier created.

2.7 KiB Raw Blame History