`ctrl_c_on_launcher_group_does_not_reach_spawned_daemon` fails in gate
stage `sweep-crdt` with "child did not exit within 5s". It is
PRE-EXISTING on main --- 72da24a fails it in a clean worktree with its
own target dir --- so while it reds, no branch can present a green
sixteen-stage gate, main included. §5b is held behind this lane.
Framing revision 1, and it proposes NO FIX, because the mechanism is not
known. What it does instead is fix the shape of the problem so the next
attempt is not another guess:
- Ground truth, cited: neither binary handles signals. `run_gpu`
(src/main.rs:324) blocks in `command.status()` with no handler, and
grepping all of pmacs-gpu/src for signal machinery returns nothing.
The probe polls at 50ms. Two processes with default SIGINT
disposition should both die at once --- this deepens the puzzle
rather than explaining it, and the framing says so.
- Ruled out by measurement, with the method for each: load, tmpfs
(tested by experiment, not argument), leaked daemons, inotify,
--workspace feature unification, and any specific preceding test.
- The reduction paradox stated as the problem's real shape: 5/5 in
the full sweep, 0/N in every reduction, including all 37 preceding
targets plus the suite.
- One retracted claim kept as a warning, because it was mine: the
"mechanism located" report described a healthy teardown. The
sampler behind it caught 394 launchers with a 5s maximum lifetime
while the failing instance must live 8s or more.
The first step is diagnostic only: an instrument keyed on the FAILING
instance --- launchers outliving ~6s --- capturing /proc/<pid>/status
signal masks, since SigIgn survives fork and exec while handlers do not.
Acceptance criteria are written now so the fix cannot quietly become
"make the test pass": a demonstrated mechanism with a mutation-tested
witness, sweep-crdt green three consecutive times, the reduction paradox
explained or recorded as unexplained, and no deadline raised or test
skipped.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016bqGA6s9tTUFzYpbeW3tai
