Complete tasks 3-7: harden verdict parsing, outputs retention, base branch, linux schedule parity, claim loop task

tasks/complete/add-state-loop-lock/VERDICT.md

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+# Verdict: add-state-loop-lock
+
+## Status: PASS
+
+## Summary
+
+Closed the TOCTOU read-modify-write race flagged in
+`add-status-brakes/ADVERSARIAL_BUG_REPORT.md` (A6) and
+`add-loop-runner/ADVERSARIAL_BUG_REPORT.md` (A2, A7) by wrapping the
+read-modify-write cycles on `.state.loop` in a cross-process file lock
+(`_loop_lock`). POSIX `fcntl.flock(LOCK_EX)`, Windows
+`msvcrt.locking(LK_LOCK, 1)`, per-loop granularity, blocking acquire,
+no timeout in v1.1. Stdlib only.
+
+## SPEC compliance
+
+| Requirement | Status |
+|-------------|--------|
+| R1 — `_loop_lock` context manager (POSIX/Windows, blocking, finally-safe FD lifecycle) | ✓ |
+| R2 — Wrap status.py `cmd_pause_loop`, `cmd_resume_loop`, `cmd_approve_loop`, `cmd_check_gate` (NOT `--create-loop`) | ✓ |
+| R3 — Wrap `cmd_tick`'s step-10 state write; lock covers `_gate` subprocess + state write | ✓ |
+| R4 — Idempotence + early-return inside `with` releases cleanly (try/finally in the context manager, not caller) | ✓ |
+| R5 — Lock file `<loop_path>/.state.lock` (per-loop granularity) | ✓ |
+| R6 — Stdlib only (`fcntl` POSIX, `msvcrt` Windows, `contextlib`, `sys`, `os`) | ✓ |
+| R7 — Existing atomic write (`_write_state_loop` tmp-then-replace) retained | ✓ |
+| D-L1 — Blocking acquire, no timeout | ✓ |
+| D-L2 — `.state.lock` per-loop, not GC'd | ✓ |
+| D-L3 — `--create-loop` unwrapped | ✓ |
+| D-L4 — Stdlib only, no `filelock` package | ✓ |
+| D-L5 — Existing atomic write retained (defense-in-depth) | ✓ |
+| D-L6 (new, necessary for SPEC R2+R3 consistency) — Env-var bypass ($AUTOMATON_NO_LOOP_LOCK=1) avoids self-deadlock when the runner spawns the `--check-gate` subprocess inside its held lock | ✓ |
+
+## Bug reports
+
+- BUG_REPORT: 5 non-blocking observations (O1-O5), all documented behaviors.
+- ADVERSARIAL_BUG_REPORT: 8 attack vectors probed (A1-A8). One LOW finding
+  (A4: harness calling loop-control command inside a tick would deadlock;
+  deferred to harness-integration contract docs follow-up). All others
+  verified safe.
+
+## Test results
+
+- `python3 -m py_compile scripts/status.py scripts/loop-runner.py` ✓
+- `python3 -m pytest tests/test_state_loop_lock.py -v` — 7 passed
+- `python3 -m pytest tests/ -q` — **447 passed** (was 440; +7 new; 0 regressions)
+- Manual: `--create-loop` does NOT leave `.state.lock` (D-L3 ✓); first
+  `--check-gate` does; `AUTOMATON_NO_LOOP_LOCK=1 status.py --check-gate`
+  works (env var bypass exercised).
+- Manual adversarial: 5 concurrent `--approve --loop` on a halted loop —
+  only one wins (code 0, resumed_count=1); 4 re-read inside the lock and
+  see status=running, exit 1. Race closed.
+- Manual adversarial: 5 concurrent `--pause-loop` — all succeed
+  (idempotent; pause is well-defined on already-paused); final state
+  consistent.
+- Manual adversarial: monkeypatch `_gate` to raise → exit exception →
+  follow-up `_loop_lock` acquires immediately (lock released in finally).
+
+## D-items applied
+
+- D-L1 to D-L6 all locked (see SPEC compliance table).
+
+## Subprocess-deadlock avoidance
+
+The original SPEC's R2 and R3 contradict each other (both list `--check-gate`
+to acquire `_loop_lock` AND the runner to acquire the same lock across the
+`--check-gate` subprocess — would deadlock). Resolved via D-L6 (env-var
+bypass). The runner sets `$AUTOMATON_NO_LOOP_LOCK=1` in the `--check-gate`
+subprocess's env ONLY (scoped via `_run_json`'s `env` kwarg, propagated to
+`_gate`'s `subprocess.run`). Harness subprocesses inherit `os.environ`
+unchanged (no env var) so their nested `status.py` calls lock normally and
+serialize against the runner's outer lock (intended for tasks; harness
+typically does `status.py --transition` only which doesn't touch
+`.state.lock`). Documented in `_loop_lock`'s docstring + design doc.
+
+## Pipeline
+
+research → research:awaiting_approval → research:approved → implement →
+code_review → code_review:awaiting_approval → code_review:approved →
+bug_find → adversarial_bug_find → doc_review → referee → complete
+
+Pipeline driven end-to-end. Ready for `--transition complete` (relocates
+to `tasks/complete/`).