concurrent-foreman-board-append-events-jsonl-race-recovery
Solution written to ~/race-recovery-solution.md, with every claim reproduced and verified in /tmp/racefix.
Three compounding root causes:
MAX(id) with a tolerant whole-file jq parse. Debris (id:null, a pretty-printed line-1 object) made jq -s abort, and the fallback returned 0, so new appends reused ids 1/2.awk ... | printf | sh fed JSON content to the shell as code; a fragment like }; rm -rf / executed, and unparseable lines were dropped (~163 committed lines lost).git checkout HEAD -- events.jsonl → pure-Python tolerant scan (json.JSONDecoder.raw_decode cursor handles compact, pretty-printed, and string-serialized objects, skipping debris) → reattach only ids > HEAD max in id order as compact JSON → validate all lines are objects and the duplicate census equals the pre-corruption baseline.flock(LOCK_EX) around id allocation and O_APPEND write; MAX(id) via anchored regex "id"\s*:\s*(\d+) over the tail 64 KB only.HEAD, reissue own events.| Check | Result |
|---|---|
| Recovery | head_max=1141 reattached=4 ids=[1142,1143,1144,1145]; 2 unrecoverable events reissued, not invented |
| Duplicate census | {1: 2} before and after (historical dup preserved, not assumed zero) |
| Old vs new allocator | jq -s slurp → 0; tail regex → 1141 |
| 60 concurrent appends, 2 sessions | 60 unique, gap-free ids 1142..1201, no duplicates |
| Freeze guard | refuses with sentinel, resumes when cleared |
The markdown is self-contained: it includes the full recover_events.py and append_event.py sources plus the exact commands.
# Evidence - Problem class: concurrent-foreman-board-append-events-jsonl-race-recovery - Model: openrouter/deepseek/deepseek-v4.1-flash - Solved: 2026-09-25T22:38:33.552Z - Verification: solution produced by pi in sandbox; see signatures.json
{"description": "Two foreman sessions appending to the same git-tracked events.jsonl interleaved appends with duplicate ids; a shell-level repair (awk piping line content through printf|sh) then destroyed ~163 lines including committed history.", "environment": "", "language": "bash+python", "model": "openrouter/deepseek/deepseek-v4.1-flash", "problem_class": "concurrent-foreman-board-append-events-jsonl-race-recovery", "provider": "openrouter", "solved_at": "2026-09-25T22:38:33.552Z", "version": ""}Solution written to ~/race-recovery-solution.md, with every claim reproduced and verified in /tmp/racefix.
Three compounding root causes:
MAX(id) with a tolerant whole-file jq parse. Debris (id:null, a pretty-printed line-1 object) made jq -s abort, and the fallback returned 0, so new appends reused ids 1/2.awk ... | printf | sh fed JSON content to the shell as code; a fragment like }; rm -rf / executed, and unparseable lines were dropped (~163 committed lines lost).git checkout HEAD -- events.jsonl → pure-Python tolerant scan (json.JSONDecoder.raw_decode cursor handles compact, pretty-printed, and string-serialized objects, skipping debris) → reattach only ids > HEAD max in id order as compact JSON → validate all lines are objects and the duplicate census equals the pre-corruption baseline.flock(LOCK_EX) around id allocation and O_APPEND write; MAX(id) via anchored regex "id"\s*:\s*(\d+) over the tail 64 KB only.HEAD, reissue own events.| Check | Result |
|---|---|
| Recovery | head_max=1141 reattached=4 ids=[1142,1143,1144,1145]; 2 unrecoverable events reissued, not invented |
| Duplicate census | {1: 2} before and after (historical dup preserved, not assumed zero) |
| Old vs new allocator | jq -s slurp → 0; tail regex → 1141 |
| 60 concurrent appends, 2 sessions | 60 unique, gap-free ids 1142..1201, no duplicates |
| Freeze guard | refuses with sentinel, resumes when cleared |
The markdown is self-contained: it includes the full recover_events.py and append_event.py sources plus the exact commands.
# Evidence - Problem class: concurrent-foreman-board-append-events-jsonl-race-recovery - Model: openrouter/deepseek/deepseek-v4.1-flash - Solved: 2026-09-25T22:38:33.552Z - Verification: solution produced by pi in sandbox; see signatures.json
{"description": "Two foreman sessions appending to the same git-tracked events.jsonl interleaved appends with duplicate ids; a shell-level repair (awk piping line content through printf|sh) then destroyed ~163 lines including committed history.", "environment": "", "language": "bash+python", "model": "openrouter/deepseek/deepseek-v4.1-flash", "problem_class": "concurrent-foreman-board-append-events-jsonl-race-recovery", "provider": "openrouter", "solved_at": "2026-09-25T22:38:33.552Z", "version": ""}