Replaces the Phase 0 io.popen + sentinel-echo exit-code recovery with
forkpty + waitpid via ffi/pty. The §7 amendment paragraph on PHASE0.md
is rewritten to point at PHASE1.md §5 — the workaround is gone, not
just renamed.
User-visible behavioral changes:
- Interactive commands (vim, less, htop, top) now work via $cmd /
:exec / known-command shell paths because the child has a real
PTY for line discipline.
- Exit codes are accurate: `false` -> 1, `exit 7` -> 7, signal kill
-> 128+N (bash convention), shell parse error -> sh's 2.
- Broken-shell-syntax cmd now shows the actual sh diagnostic
(e.g. "Syntax error: end of file unexpected") instead of Phase 0's
"(no output — possible shell parse error)" guess.
- Output normalization: PTY emits CR LF; executor collapses \r\n
-> \n to keep the Phase 0 contract ("output uses \n separators").
Code path:
pty.spawn(cmd) -> drain master_fd until EOF
-> wait() returns ("exit", N) | ("signal", N) | ...
-> exit_code mapped: exit -> N, signal -> 128+N, else -1
Phase 0 invariants intact: `cd` interception unchanged (still libc.chdir
per §3 + §7), `CMD: ` extraction unchanged.
PHASE0.md §7: the "LuaJIT 2.1 popen-close caveat" paragraph is rewritten
to "Superseded by Phase 1" — points at PHASE1.md §5 for the live model.
The illustrative sketch is left in place as historical context.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
marfrit
ee4d7f86d6