{"abstract":"An entry remains visible at precisely its expiration instant.","category":"Caching","checks":3,"contract":"Treat the valid interval as insertion time inclusive and expiration time exclusive.","evaluation_group":"model-cb10a90c54731159","failed_approach":"Subtracting one tick expires values before their actual deadline.","family":"ttl-boundary","id":"FA-006","implementations":{"attempt":{"sha256":"041030b16cdb07eb54d70503580e94633ea6ab5c956a68b63252a8f17c20377c","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(value, now, expires):\n    return value if now < expires - 1 else None\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('exact expiration', solve('record', N, N), None)\ncheck('last valid half tick', solve('record', N-0.5, N), 'record')\ncheck('past deadline', solve('record', N+1, N), None)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"f913cbdf9831d939d8dc0c0506d685ddb6628c67bb964c788fa18ac6bd2f70dd","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(value, now, expires):\n    return value if now <= expires else None\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('exact expiration', solve('record', N, N), None)\ncheck('last valid half tick', solve('record', N-0.5, N), 'record')\ncheck('past deadline', solve('record', N+1, N), None)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"fixed":{"sha256":"32628d76a52605e8ff3d5b61888981c4953bc5e4383a5f21cfe1911e8337de30","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(value, now, expires):\n    return value if now < expires else None\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('exact expiration', solve('record', N, N), None)\ncheck('last valid half tick', solve('record', N-0.5, N), 'record')\ncheck('past deadline', solve('record', N+1, N), None)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":" This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"ttl-boundary","generated_at":"2026-09-29T14:36:49.844634+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A compact reasoning and repair task with executable evidence.","repair":"Treat the valid interval as insertion time inclusive and expiration time exclusive.","root_cause":"The expiration comparison treats the deadline as an inclusive valid instant.","sha256":"2945a1c4c96085530fcadb1a4d493c4c79a2df79c99c40d429dc8b71c13bd947","title":"An expired cache entry survives its deadline · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":31.327,"exit_code":1,"observations":[{"actual":null,"check":"exact expiration","expected":null,"passed":true},{"actual":null,"check":"last valid half tick","expected":"record","passed":false},{"actual":null,"check":"past deadline","expected":null,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"exact expiration\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"last valid half tick\", \"actual\": null, \"expected\": \"record\", \"passed\": false}, {\"check\": \"past deadline\", \"actual\": null, \"expected\": null, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":36.091,"exit_code":1,"observations":[{"actual":"record","check":"exact expiration","expected":null,"passed":false},{"actual":"record","check":"last valid half tick","expected":"record","passed":true},{"actual":null,"check":"past deadline","expected":null,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"exact expiration\", \"actual\": \"record\", \"expected\": null, \"passed\": false}, {\"check\": \"last valid half tick\", \"actual\": \"record\", \"expected\": \"record\", \"passed\": true}, {\"check\": \"past deadline\", \"actual\": null, \"expected\": null, \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":34.055,"exit_code":0,"observations":[{"actual":null,"check":"exact expiration","expected":null,"passed":true},{"actual":"record","check":"last valid half tick","expected":"record","passed":true},{"actual":null,"check":"past deadline","expected":null,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"exact expiration\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"last valid half tick\", \"actual\": \"record\", \"expected\": \"record\", \"passed\": true}, {\"check\": \"past deadline\", \"actual\": null, \"expected\": null, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}