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

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gem5 test infrastructure — Timer-based timeout + typed exceptions

Metadata

Field	Value
Institute	Molodetz Institute — Research & Retrieval Division
Subject	async-pty-process-testing
Document type	Source Dossier
Tier	1
Source title	tests: Add test infrastructure as a Python module (commit), and companion helpers.py
Source URL	https://git.sanchayanmaity.net/sanchayanmaity/gem5/commit/f385adc8af744e7f6b78ff9adafd9c3ecf65ce68
Source publisher / author	gem5 project (computer architecture simulator)
Source type	repository (commit + source file)
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	High
Status	Active

Summary

A commit adding Python test infrastructure to the gem5 simulator project, together with its companion tests/testing/helpers.py. The helper uses a threading.Timer to enforce a timeout on a running subprocess: the timer's callback terminates the child process, then the surrounding code raises a dedicated exception carrying both the captured exit status and the process's output.

Key findings

Timeout enforcement pattern: Timer(timeout, on_timeout_handler) started before communicate()-ing with the process, cancelled afterward if the process finished in time.
On timeout, the handler terminates the child and a dedicated exception type is raised carrying the captured status and output together — the caller doesn't have to separately go fetch output after catching a generic timeout error.
gem5's newer test framework (noted in the same research pass) further splits each test into a "run" stage and a "verify" stage, where verify units are automatically skipped if their corresponding run stage didn't execute.

Pros / strengths

The "exception carries the captured output" design is directly actionable and immediately reusable — it solves the exact problem of "how do you debug a timed-out test" by attaching the evidence to the failure itself rather than requiring separate log inspection.
The run/verify stage split is a clean idea for keeping a test's "did it crash" question separate from "did it produce the right result."

Cons / limitations / caveats

Uses threading.Timer, a synchronous/thread-based mechanism, not asyncio.wait_for — tai_test.py adapted the idea (typed exception carrying output) to an asyncio-native mechanism (asyncio.wait_for plus try/except) rather than reusing gem5's thread-based implementation directly.
Reviewed via commit metadata and the helper file's described behavior, not gem5's full test suite or its actual usage patterns in practice.

Relevance to tai

The direct model for tai_test.py's exception hierarchy: TestTimeout, TestCrashed, and TestAssertionFailed all subclass TaiTestError, which carries a transcript list — so a failing test's exception is the debugging evidence, exactly matching gem5's "exception carries status and output" pattern, just built on asyncio.wait_for/try-except instead of threading.Timer.

Changelog

Date	Change
2026-10-09	Initial dossier created.

3.2 KiB Raw Blame History