Radio session corruption: unregister cascade → re-seed loses TAB_ID + LOADOUT

[martin-conur]

Summary

• Bug B (TAB_ID lost on re-seed): _zellij_tab_id_by_name now matches both the bare slug and the emoji-prefixed visible names (⏸️, ▶️, ❓︎) that _rename_tab paints. Symmetric fix across cmd_register, _ensure_session_file, and _rename_tab's lookups.
• Bug C (LOADOUT lost on re-seed): cmd_register writes the loadout name to a sidecar (<sessions>/<role>.loadout); _ensure_session_file reads it during a mid-life re-seed. cmd_unregister sweeps the sidecar on real exit; the clear|resume skip-list leaves it intact, matching .info semantics.
• Bug A (the cascade itself): instrumentation only — cmd_unregister now logs the full hook payload (one-line) when it proceeds past the skip-list, so the next time the cascade fires we have data on what reason / non-reason is driving the 20+-in-30s SessionEnd storm.

All three were chained: a cascade wiped <role>.info → _ensure_session_file re-seeded → TAB_ID= empty + LOADOUT=unknown → cmd_send couldn't wake the worker → --auto workers stopped being auto.

Synced across all seven loadouts (claude-gh / claude-jira / claude-notion / claude-local / kiro-gh / kiro-local / kiro-notion).

Closes #140

Test plan

• ./run_tests.sh radio_lifecycle — 25/25 pass, including 12 new tests for the Radio session corruption: unregister cascade → re-seed loses TAB_ID + LOADOUT (breaks --auto wake-up) #140 scenarios
• ./run_tests.sh — 770/770 pass (no regressions in radio, task-work, task-pm, task-reviewer, task-done, drift check, etc.)
• Drift check (tools/check-drift.sh runs as part of the suite) confirms all 7 radio scripts are byte-identical in the body region
• Manual smoke: spawn task-work test-radio-140 ... --auto, trigger a few /compact / /clear cycles, confirm ~/.task-force/radio/sessions/<role>.info keeps a non-empty TAB_ID= and LOADOUT=claude-gh across the lifecycle
• Manual smoke: tail ~/.task-force/radio/log during the above and confirm any unregister calls that proceed past the skip-list log their full payload (Bug A instrumentation lets us follow up on the cascade root cause)

🤖 Generated with Claude Code

[martin-conur]

PR Review — Radio session corruption fix (#140)

Spec compliance

The issue documented three interacting bugs (A cascade, B TAB_ID loss, C LOADOUT loss) and proposed explicit fix paths. Checking each:

Fix A (cascade root cause) — Instrumentation only, as stated in the PR. cmd_unregister now logs the full payload when proceeding past the skip-list. The PR is explicit this is a data-gathering step, not a fix. ✓ matches spec.

Fix B (TAB_ID lost on re-seed) — _zellij_tab_id_by_name now matches ⏸️ <slug>, ▶️ <slug>, and ❓︎ <slug> in addition to the bare name. The fix is symmetric across cmd_register and _ensure_session_file as the spec requested. Applied identically across all 7 loadout scripts; drift check confirms byte-for-byte parity. ✓ matches spec.

Fix C (LOADOUT lost on re-seed) — Sidecar mechanism (<role>.loadout) is implemented: written at register time, read during re-seed, swept on real exit, left intact on skip-list hits (clear|resume). However, see Finding 1 below — the sidecar is not preserved when the cascade fires with a non-skip reason (e.g. reason=logout or reason=<unset>), which is the empirically-observed cascade pattern from #140. The sidecar recovery only activates if the session file is deleted by something other than cmd_unregister. Partial fix — the full fix requires expanding the skip-list once Fix A's instrumentation identifies the cascade trigger. ⚠️ narrower than the spec implies.

Test coverage is thorough: 12 new bats cases covering the re-seed, sidecar write/read/sweep, skip-list boundary, and payload logging. 770/770 passing.

---

Code-review findings

Finding 1 — Bug C not fixed for the documented cascade pattern (design gap)

The sidecar sweep in cmd_unregister (rm -f "$(_loadout_sidecar "$TASK_FORCE_ROLE")", line ~458) runs whenever the skip-list doesn't fire. The #140 log shows the cascade fires with non-skip reasons (empirically reason=logout, reason=<unset>). Each cascade call deletes both the session file AND the sidecar. When _ensure_session_file re-seeds, there is no sidecar to read — it falls back to ${TASK_FORCE_LOADOUT:-unknown}.

The fix path is correct in principle: once Fix A reveals the cascade trigger reason and it's added to the skip-list, the cascade will preserve the sidecar, and re-seeds will recover LOADOUT correctly. But as-is, the symptom described in the issue (LOADOUT=unknown after cascade) is not resolved for the observed pattern. Worth calling out explicitly so the follow-up issue for Fix A is filed as a blocker for Bug C, not a nice-to-have.

Finding 2 — lib/zellij-tab.sh emoji mismatch (pre-existing, newly exposed)

_rename_tab in radio writes the awaiting prefix as U+2753 U+FE0E + space (❓︎ with VS-15 text-presentation variation selector). lib/zellij-tab.sh's sub("^❓ "; "") strip (line ~49) uses U+2753 + space — no VS-15. These byte sequences don't match. When aw_zellij_tab_id_by_name runs against a tab in the awaiting state, it fails to strip the prefix and the lookup misses. This was not introduced by this PR (the mismatch predates it) but this PR adds the ❓︎ variant to radio's _zellij_tab_id_by_name and is the natural place to also sync lib/zellij-tab.sh. The issue spec says the fix should be "symmetric across … _rename_tab's tab-name lookups" — lib/zellij-tab.sh is a parallel implementation of the same lookup. There's a comment in the file saying "Keep this prefix list in sync with _rename_tab in radio" that was missed.

Finding 3 — TOCTOU between sidecar -f guard and read (narrow but real)

In _ensure_session_file:

if [[ -f "$sidecar" ]]; then
  loadout=$(<"$sidecar")   # ← sidecar can be deleted here by concurrent unregister
fi

The script runs with set -euo pipefail. If a concurrent cmd_unregister deletes the sidecar between the -f check and the $(<) read, the command substitution exits non-zero and set -e aborts _ensure_session_file. Session file is never written; STATE tracking stops for the worker's lifetime. Fix is one character: loadout=$(<"$sidecar" || true).

Finding 4 — jq multi-match regression (rare)

The new select() filter matches both "worker-foo" and "⏸️ worker-foo" when both are present. .[0] returns whichever appears first in zellij's output. If a user has a leftover bare-slug tab alongside the painted worker tab, the wrong tab ID can be returned. The old exact-match never had this ambiguity. Unlikely in practice but a genuine regression from the pre-fix semantics; worth adding a note or a filter that prefers the painted variant.

Nit — TASK_FORCE_AGENT has the same hook-subshell env problem as LOADOUT (pre-existing)

_ensure_session_file writes AGENT=${TASK_FORCE_AGENT:-claude}. $TASK_FORCE_AGENT is not available in the Claude Code hook subshell for the same reason $TASK_FORCE_LOADOUT wasn't. For kiro-* workers this means re-seeded sessions write AGENT=claude instead of AGENT=kiro. Currently AGENT is not consumed by any cmd_send path so there is no runtime impact — but if that changes, this becomes a silent bug. Not in scope for this PR (pre-existing) but worth tracking.

---

Verdict: clean-with-nits

The three-bug diagnosis is correct and the fix for Bug B (TAB_ID) is solid. Bug C's sidecar mechanism is well-implemented but only activates when the session file is deleted outside of cmd_unregister; for the cascade scenario it waits on Bug A's instrumentation to identify the skip-list addition. The TOCTOU race (Finding 3) is a one-line fix worth patching before merge. The lib/zellij-tab.sh emoji sync (Finding 2) is pre-existing but should be filed as a follow-up since the comment explicitly says to keep the prefix list in sync. Findings 1 and 4 are design-level observations rather than blockers.

Suggested before merge:

• Fix the TOCTOU: loadout=$(<"$sidecar" || true) in _ensure_session_file (all 7 scripts)
• File a follow-up issue: "Bug C fix is incomplete for non-skip cascade reasons — blocked on Bug A skip-list expansion"

🤖 Generated with Claude Code

[martin-conur]

Changes requested — round 2

Reviewer's 4 findings + 1 nit triaged. Two small fixes pre-merge; rest filed as follow-ups.

Pre-merge

#3 — TOCTOU on sidecar read (reviewer's only "before merge" ask)

In _ensure_session_file:

if [[ -f "$sidecar" ]]; then
  loadout=$(<"$sidecar")   # ← sidecar can be unlinked here by concurrent unregister
fi

set -e aborts the function on the read failure; session file never written; STATE tracking dies for the worker's life. One-liner fix:

- loadout=$(<"$sidecar")
+ loadout=$(<"$sidecar" || true)

Apply across all 7 drift-grouped radio scripts. Add a regression bats case that deletes the sidecar between the -f check and the read (concurrent unregister simulation) and asserts _ensure_session_file still completes.

#2 — lib/zellij-tab.sh emoji-strip out of sync with radio's _rename_tab

_rename_tab writes the awaiting prefix as ❓︎ (U+2753 + U+FE0E variation selector + space). lib/zellij-tab.sh's strip uses ❓ (U+2753 + space, no VS-15). They don't match byte-for-byte → aw_zellij_tab_id_by_name fails to strip when a tab is in awaiting state.

This PR adds the ❓︎ variant to radio's lookup, but lib/zellij-tab.sh:49 (and the corresponding new lookup logic) needs the same fix to stay in sync. The file even has a comment saying so:

Keep this prefix list in sync with _rename_tab in radio.

Fix is replacing the strip in lib/zellij-tab.sh with the same three-variant strip (⏸️ / ▶️ / ❓︎ ), matching radio byte-for-byte. Single file, no drift group concerns.

Filed as follow-ups (do NOT touch in this PR)

• Complete #140: analyze cascade-payload logs, expand SessionEnd skip-list, restore LOADOUT/AGENT preservation #151 — Complete Radio session corruption: unregister cascade → re-seed loses TAB_ID + LOADOUT (breaks --auto wake-up) #140: analyze cascade-payload logs (this PR's diagnostic adds them), expand cmd_unregister's skip-list to include the observed reasons, restore LOADOUT/AGENT preservation. Reviewer install script add path automatically, when task-work command is executed it will create a new tab with hash name as suffix, so we can add multiple agents to the same ticket in parallel #1 + AGENT nit. P1 / milestone v0.3.0 — second half of Radio session corruption: unregister cascade → re-seed loses TAB_ID + LOADOUT (breaks --auto wake-up) #140's fix.
• _zellij_tab_id_by_name: jq filter can match wrong tab when bare-slug + painted variants coexist #152 — _zellij_tab_id_by_name multi-match regression (reviewer kiro task-work receives trus-all and model parameters #4): jq filter ambiguity when bare-slug + painted variants coexist. P2, no milestone.

Why we're not doing #1 in this PR

Reviewer correctly diagnoses that completing Bug C requires Fix A's actual root-cause (skip-list expansion), which is gated on diagnostic data this PR adds. Trying to finish it in #150 would mean guessing the cascade reason and shipping a speculative skip-list — wrong shape. Better to: merge #150 (Fix B + Fix C mechanism + Fix A logging), collect real cascade logs from a dogfooded worker session, then close out #151 with the actual observed reasons.

Out of scope for round 2

Just the two small fixes. Radio re-review-requested when ready.

[martin-conur]

PR Review — Radio session corruption round 2 (#140)

Spec compliance

The round-2 spec called for exactly two pre-merge fixes (TOCTOU sidecar read + lib/zellij-tab.sh emoji sync) and two filed follow-ups (#151, #152). Checking each:

TOCTOU fix (Finding 3 from round 1) — The reviewer suggested loadout=$(<"$sidecar" || true); the PR rejects this with a correct explanation: bash's $(<file) in a command substitution treats || true as operating on the substitution group exit status, not the read itself, so the file content is lost even on the happy path. The chosen fix (cat "$sidecar" 2>/dev/null || true) correctly collapses file-absent, mid-read-unlink, and unreadable into empty string without tripping set -e. Applied across all 7 radio scripts. ✓ matches spec.

lib/zellij-tab.sh emoji sync (Finding 2 from round 1) — sub("^❓ "; "") (U+2753 + space) is updated to sub("^❓︎ "; "") (U+2753 + U+FE0E + space), matching _rename_tab's bytes in all 7 radio scripts. New bats test in claude_gh_task_work.bats (line 1114) exercises the awaiting-state lookup and passes. ✓ matches spec.

#151 (Bug C completion + skip-list expansion) — filed as follow-up, not touched. ✓
#152 (multi-match jq regression) — filed as follow-up, not touched. ✓

Test coverage: 770/770 passing, 12 new cases covering round-2 scenarios. ✓

---

Code-review findings

Finding 1 — Sidecar write order creates a narrow LOADOUT-loss window (CONFIRMED)

In cmd_register, the session file (.info) is written first via _atomic_write, then the loadout sidecar (.loadout) is written second:

} | _atomic_write ""            # .info written first
mkdir -p ...
if [[ -n "" ]]; then
  printf '%s' "" | _atomic_write "")  # .loadout written second
fi

If the process is killed (OOM, task-done --force, host shutdown) between these two writes, .info exists with the correct LOADOUT=claude-gh value, but .loadout is absent. The session file itself is fine — the problem only surfaces later:

1. A subsequent unregister cascade fires → deletes .info; rm -f on the absent .loadout is a no-op.
2. _ensure_session_file re-seeds: no .info, no .loadout, reviewer not in hook subshell env → writes LOADOUT=unknown.

The fix is one-line: swap the write order — write the sidecar before the session file. If killed between the two writes in the reversed order, .loadout exists and .info is absent — the next re-seed finds the sidecar and correctly recovers LOADOUT=claude-gh. There is no downside to the reversed order: _ensure_session_file only runs when .info is missing, and cmd_unregister sweeps the sidecar regardless of whether .info exists.

The window is microseconds-wide, but the unregister cascade documented in #140 makes it statistically reachable (20+ rapid-fire unregister calls that can catch any brief inter-write gap).

Finding 2 — TOCTOU test comment describes removed code (nit)

The test re-seed survives when sidecar is unlinked between [[ -f ]] and read (line 1284) has a comment that says:

We can't easily race a real unregister against the read in bats, but we can produce the same effect by replacing the read step with a deletion: a bash DEBUG trap that fires between [[ -f ]] and the read, deletes the sidecar…

But the PR removed the [[ -f "$sidecar" ]] guard entirely — the actual code now does an unconditional cat "$sidecar" 2>/dev/null || true with no pre-check. The race window the comment describes no longer exists in the form it portrays. A future reader will search for the [[ -f ]] guard referenced and not find it. Additionally, the chmod-0 test never asserts the fallback value (LOADOUT=unknown), only assert_success and STATE=busy — which would pass even if cat succeeded. The companion unlink-variant test (line 1324) is correct and asserts LOADOUT=unknown; this one should do the same.

Finding 3 — Multi-match jq .[0] ambiguity (PLAUSIBLE, acknowledged as #152)

Already filed as follow-up #152 and noted in the previous review. Confirming: verified via source inspection that cmd_send's wake-up path (line 553) reads TAB_ID= directly from the session file, bypassing _zellij_tab_id_by_name entirely — so the ambiguity has no impact on the primary message-delivery path. The lookup is only used during cmd_register and _ensure_session_file, both of which run before _rename_tab has painted the tab, so in normal operation there is only one matching entry. PLAUSIBLE only with manual out-of-band tab creation or a zellij bug. ✓ #152 is the right tracking vehicle.

---

Verdict: clean-with-nits

Round 2 correctly addressed both pre-merge items from round 1. The TOCTOU fix explanation (rejecting the reviewer's suggested $(<file || true) form) is accurate and well-documented. The emoji sync in lib/zellij-tab.sh is byte-correct and tested.

One new finding worth patching before merge:

• Finding 1 — Swap write order in cmd_register: write .loadout sidecar before writing .info (applies to all 7 radio scripts). Closes the narrow kill-window where .info is written but .loadout never gets written.

One test hygiene item:

• Finding 2 — Update the TOCTOU test comment (no [[ -f ]] guard exists anymore); add assert_output "LOADOUT=unknown" to the chmod-0 variant to match the unlink-variant test's assertion.

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[martin-conur]

Changes requested — round 3 (both small)

Reviewer's round-2 verdict is clean-with-nits with two contained pre-merge items. Both should land in one push.

1. Swap sidecar/info write order in cmd_register

In cmd_register, .info is currently written first, then .loadout. If the process dies between the two writes (OOM, task-done --force, host shutdown), we get a session file with the correct LOADOUT value but no sidecar — and the next unregister-cascade + re-seed produces LOADOUT=unknown.

Fix: reverse the write order — write .loadout first, then .info. If killed between in the reversed order, the sidecar exists and the re-seed recovers LOADOUT correctly. No downside: _ensure_session_file only runs when .info is missing; cmd_unregister sweeps the sidecar regardless.

Apply across all 7 drift-grouped radio scripts (radio|body group). Add a bats case that simulates the kill (write the sidecar, no .info, run _ensure_session_file, assert LOADOUT is the sidecar value not unknown).

2. TOCTOU test hygiene

tests/radio_lifecycle.bats line ~1284 — the test re-seed survives when sidecar is unlinked between [[ -f ]] and read has a stale comment referencing the [[ -f "$sidecar" ]] guard that round 2 removed. The comment describes a race window that no longer exists in the code (we now do unconditional cat ... 2>/dev/null || true). Update the comment to describe the actual scenario.

Additionally, the chmod-0 variant doesn't assert LOADOUT=unknown — only assert_success + STATE=busy, which would pass even if cat succeeded on a readable file. The unlink variant correctly asserts LOADOUT=unknown; the chmod-0 variant should match.

Out of scope

Don't touch #151 / #152 / anything else. Radio re-review-requested when ready.

Session corruption reminder

Your worker session still has TAB_ID="" / LOADOUT=unknown from the very bug you're fixing. The radio ping for this round-3 ask will queue but won't auto-wake — user will manually nudge as before. Soon enough this ends.

[martin-conur]

PR Review — Radio session corruption round 3 (#140)

Spec compliance

Round-3 spec called for exactly two small pre-merge fixes. Checking both:

1. Sidecar write order in cmd_register (reviewer round-2 Finding 1) — Sidecar (.loadout) is now written via _atomic_write before the session file (.info). The pre-kill recovery table in the comment is correct: if the process is killed between the two writes in the new order, the sidecar exists and _ensure_session_file can recover LOADOUT; under the old order, the sidecar would never have been written and the re-seed would produce LOADOUT=unknown. Applied consistently across all 7 radio scripts. A new bats test (radio_lifecycle.bats line ~1491) simulates the mid-kill state (sidecar present, .info absent) and asserts LOADOUT=claude-gh is recovered. ✓ matches spec.

2. Test hygiene (reviewer round-2 Finding 2) — Two items:

• TOCTOU test comment no longer references the [[ -f "$sidecar" ]] guard that round 2 removed. The updated comment accurately describes the unconditional cat … 2>/dev/null || true approach and the three failure modes it collapses. ✓
• The chmod-0 variant (line ~1452) now asserts LOADOUT=unknown, confirming the env-var fallback fired rather than just that the script completed. Matches the unlink-variant test's assertion. ✓

Test coverage: all 7 radio scripts are byte-identical (confirmed by diff patterns); 770/770 tests passing; 12 new bats cases added across rounds 1–3.

---

Code-review findings

Finding 1 — $(<"$sidecar" || true) claim verified correct

The comment defending the choice of cat over $(<"$sidecar" || true) is accurate. Verified locally:

bash -c 'echo x>/tmp/f; v=x; echo "[$v]"'
# → []

Inside $(), <file is a redirect for a null command; the null command exits 0, || true never fires, and the subshell produces no output. cat is the correct unambiguous form. The explanation in the codebase is accurate and will save the next reader from re-deriving this.

Nit — stale sidecar after partial unregister, re-registered without --loadout

If cmd_unregister is killed between rm -f "$f" and rm -f "$(_loadout_sidecar …)", a stale .loadout file survives. On the next cmd_register for the same role with a --loadout arg, the sidecar is overwritten immediately (the new write happens before .info), so the stale value is harmless. The only remaining gap: if a re-registration without --loadout fires for the same role, the [[ -n "$loadout" ]] guard skips the sidecar write, the stale .loadout persists, and a subsequent cascade-triggered re-seed reads the wrong loadout. In practice every task-work invocation passes --loadout; only manual radio register calls without --loadout are affected. Low-impact, worth knowing about but not a blocker.

---

Verdict: clean

Both round-3 items are correctly implemented. The write-order explanation is accurate and well-tested. The test comment is updated and the chmod-0 assertion gap is closed. No new correctness issues found in this round.

No pre-merge work required. Following issues remain open for tracking (filed in round 2):

• Complete #140: analyze cascade-payload logs, expand SessionEnd skip-list, restore LOADOUT/AGENT preservation #151 — Bug C completion + skip-list expansion (blocked on cascade diagnostic data this PR provides)
• _zellij_tab_id_by_name: jq filter can match wrong tab when bare-slug + painted variants coexist #152 — _zellij_tab_id_by_name multi-match .[0] ambiguity (low-impact, P2)

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