shoney.arickathil
6e997759e5
- five stories status: done; 00-story records the one-run landing - spec History: three implementation amendments (Signal record not scalar, caller-owned stdio fds, handler-latch instead of signalfd) - board NEXT PLAN entry with measured findings (zero transport code added; the tty-across-the-socket handover proven; the double-raw refusal restoring the terminal — the "bug" that was the design working); section rows flipped; graph nodes green - CODE-LOGIC.md: the runtime-v2 section - full belt quoted on the board: suites 0 fail both flavors (test_proc 193/0, test_term 60/0), woc 557/0, subprocess 12/0, site 23/0 Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> (cherry picked from commit bc1b4f070693eb755ad6a9fd0c853fb3e2bda347)
47 lines
1.9 KiB
Markdown
47 lines
1.9 KiB
Markdown
---
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track: runtime-v2
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iteration: "2"
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status: done
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readiness: ready
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---
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# runtime-v2 2 — PTY: a child that believes it owns a terminal
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> Part of [Story — runtime-v2: the runtime beyond sockets](00-story.md).
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> After [1](01-streaming-subprocess.md): a streaming child whose stdio
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> is a pseudo-terminal instead of pipes. A shell run over pipes disables
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> its prompt, its line editing and its job control; a multiplexer is
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> pointless without them.
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>
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> **The problem.** Nothing can allocate a PTY pair, place the child on
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> the slave side as its controlling terminal, or resize it. The
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> reference reading is `.dev/reference/tmux` `spawn.c` +
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> `compat/fdforkpty.c` (~450 lines of C covering five platforms; Linux
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> alone is far smaller).
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## Info — the forks, settled (brainstorm 2026-09-01; spec:
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[`2026-09-01-runtime-v2-design.md`](../../superpowers/specs/2026-09-01-runtime-v2-design.md))
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1. **Separate verb**: `proc.spawn_pty(cmd, args, cols, rows) -> ?Child`
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— its own builtin id (static arity table stays static), same Child
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record with `in` and `out` both the master fd, `err` nil.
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2. **Resize ships HERE**: `proc.resize(id, cols, rows)` → TIOCSWINSZ on
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the slot; refusal by name on a pipe child.
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3. **Transport settled by iteration 1's pull decision** — the master fd
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is driven by the existing net verbs, nothing new.
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4. **Master raw by default, no knobs** — until a consumer asks by name.
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(`openpty` may need `-lutil` — the plan verifies the link line
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before assuming.)
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## Acceptance sketch
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- A real shell spawned on a PTY prints a PROMPT (it never does over
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pipes) — asserted on the bytes.
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- Resize: the child (a script reading TIOCGWINSZ) observes the new size.
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- `isatty` inside the child answers yes on all three fds.
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- Kill/reap/stop legs identical to 1's, PTY edition; fd count flat.
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## Consumers
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wmux 1 (every pane), the alacritty study's stage A (the headless
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expect-clone is exactly "spawn on a PTY, script it, assert").
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