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

3.0 KiB

Raw Blame History

Ptyprocess — Ptyprocess 0.7 documentation

Metadata

Field	Value
Institute	Molodetz Institute — Research & Retrieval Division
Subject	async-pty-process-testing
Document type	Source Dossier
Tier	1
Source title	Ptyprocess — Ptyprocess 0.7 documentation
Source URL	https://ptyprocess.readthedocs.io/en/latest/
Source publisher / author	ptyprocess maintainers (readthedocs project)
Source type	vendor docs
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

Ptyprocess is a Python library for spawning a child process attached to a real pseudo-terminal (pty) rather than plain pipes. Its documentation describes the behavioral guarantees a real pty gives you that a pipe cannot: unified stdio, window-size tracking with SIGWINCH delivery, and line-discipline signal generation (Ctrl-C becomes SIGINT).

Key findings

When a program runs under ptyprocess, all three of its standard streams (stdin/stdout/stderr) are connected to a single pty, not three separate pipes.
Ptyprocess tracks the terminal's window size and notifies the child process with a SIGWINCH signal when it changes.
In cooked (line-buffered) terminal mode, the kernel's tty line discipline turns a Ctrl-C keystroke (byte 0x03) into a SIGINT delivered to the foreground process group — this only happens because the device is a real pty, not a pipe.

Pros / strengths

Documents, in one place, exactly which "feels like a real terminal" behaviors a pty provides that a pipe does not — this is the core justification for why tai_test.py needed pty support at all, since tai.py's own code branches on sys.stdin.isatty().
The SIGWINCH and line-discipline-SIGINT points are concrete, testable claims, not vague marketing.

Cons / limitations / caveats

The dossier is based on a web-search synthesis of the documentation, not a full read of the library's source or a hands-on trial of ptyprocess itself — tai_test.py does not depend on ptyprocess as a library, only on the general pty behavior it documents (which was reimplemented directly against the stdlib pty module).
Says nothing about asyncio integration; ptyprocess itself is a synchronous/blocking library.

Relevance to tai

Directly informed the decision to give tai_test.py's pty mode a real pseudo-terminal rather than a pipe, since tai.py branches on isatty() for approval prompts and readline behavior. The SIGWINCH/Ctrl-C-SIGINT behaviors this source describes are explicitly not relied on by tai_test.py — see the companion dossier on the start_new_session/controlling-terminal pitfall (github-agents-issue1-controlling-terminal.md) and the framework's own documented limitation in its module docstring.

Changelog

Date	Change
2026-10-09	Initial dossier created.

3.0 KiB Raw Blame History