{"abstract":"An event with a later wall-clock reading is placed after an event that actually occurred later in UTC.","category":"Time representation","checks":7,"contract":"Given [identifier, ISO timestamp] records with explicit numeric offsets, return identifiers in increasing absolute-time order. Keep input order for ties. This models explicit fixed offsets only, not named-zone DST resolution.","evaluation_group":"model-1b761dff2541a9b4","failed_approach":"Parsing timestamps but discarding their timezone information still compares wall clocks from different offsets.","family":"time-offset-instant-order","id":"FA-306","implementations":{"attempt":{"sha256":"2c7fb19a50771c3a060a3bb13a561d86fe57b2a515e3adfe6ef557221ac408c8","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom datetime import datetime, timezone\nN = 1\nobservations = []\ndef solve(records):\n    return [record[0] for record in sorted(records, key=lambda record: datetime.fromisoformat(record[1]).replace(tzinfo=None))]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\noffset = N + 1\ncheck('positive offset reverses wall-clock order', solve([['east', f'2024-01-01T10:00:00+{offset:02d}:00'], ['utc', '2024-01-01T09:00:00+00:00']]), ['east', 'utc'])\ncheck('negative offset reverses wall-clock order', solve([['west', '2024-01-01T08:00:00-05:00'], ['utc', '2024-01-01T12:00:00+00:00']]), ['utc', 'west'])\ncheck('equal instants keep input order', solve([['first', '2024-01-01T10:00:00+02:00'], ['second', '2024-01-01T08:00:00+00:00']]), ['first', 'second'])\ncheck('offset crosses calendar date', solve([['next-local-day', '2024-01-02T00:00:00+14:00'], ['same-utc-day', '2024-01-01T23:00:00+00:00']]), ['next-local-day', 'same-utc-day'])\ncheck('fractional seconds retain order', solve([['later', '2024-01-01T00:00:00.002000+00:00'], ['earlier', '2024-01-01T00:00:00.001000+00:00']]), ['earlier', 'later'])\ncheck('single record', solve([['only', f'2024-01-0{N}T00:00:00+00:00']]), ['only'])\ncheck('no records', solve([]), [])\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":"185b2aa41d676c10b81bdeda9123bb920605ebc1167a01e51022257432b1e1dc","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom datetime import datetime, timezone\nN = 1\nobservations = []\ndef solve(records):\n    return [record[0] for record in sorted(records, key=lambda record: record[1])]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\noffset = N + 1\ncheck('positive offset reverses wall-clock order', solve([['east', f'2024-01-01T10:00:00+{offset:02d}:00'], ['utc', '2024-01-01T09:00:00+00:00']]), ['east', 'utc'])\ncheck('negative offset reverses wall-clock order', solve([['west', '2024-01-01T08:00:00-05:00'], ['utc', '2024-01-01T12:00:00+00:00']]), ['utc', 'west'])\ncheck('equal instants keep input order', solve([['first', '2024-01-01T10:00:00+02:00'], ['second', '2024-01-01T08:00:00+00:00']]), ['first', 'second'])\ncheck('offset crosses calendar date', solve([['next-local-day', '2024-01-02T00:00:00+14:00'], ['same-utc-day', '2024-01-01T23:00:00+00:00']]), ['next-local-day', 'same-utc-day'])\ncheck('fractional seconds retain order', solve([['later', '2024-01-01T00:00:00.002000+00:00'], ['earlier', '2024-01-01T00:00:00.001000+00:00']]), ['earlier', 'later'])\ncheck('single record', solve([['only', f'2024-01-0{N}T00:00:00+00:00']]), ['only'])\ncheck('no records', solve([]), [])\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":"1a8d37a19600895d654cba9ff5dd669da48c29ddf6c5e42bc6cbca5c90371654","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom datetime import datetime, timezone\nN = 1\nobservations = []\ndef solve(records):\n    return [record[0] for record in sorted(records, key=lambda record: datetime.fromisoformat(record[1]).astimezone(timezone.utc))]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\noffset = N + 1\ncheck('positive offset reverses wall-clock order', solve([['east', f'2024-01-01T10:00:00+{offset:02d}:00'], ['utc', '2024-01-01T09:00:00+00:00']]), ['east', 'utc'])\ncheck('negative offset reverses wall-clock order', solve([['west', '2024-01-01T08:00:00-05:00'], ['utc', '2024-01-01T12:00:00+00:00']]), ['utc', 'west'])\ncheck('equal instants keep input order', solve([['first', '2024-01-01T10:00:00+02:00'], ['second', '2024-01-01T08:00:00+00:00']]), ['first', 'second'])\ncheck('offset crosses calendar date', solve([['next-local-day', '2024-01-02T00:00:00+14:00'], ['same-utc-day', '2024-01-01T23:00:00+00:00']]), ['next-local-day', 'same-utc-day'])\ncheck('fractional seconds retain order', solve([['later', '2024-01-01T00:00:00.002000+00:00'], ['earlier', '2024-01-01T00:00:00.001000+00:00']]), ['earlier', 'later'])\ncheck('single record', solve([['only', f'2024-01-0{N}T00:00:00+00:00']]), ['only'])\ncheck('no records', solve([]), [])\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":"time-offset-instant-order","generated_at":"2026-09-29T14:36:52.069144+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Correlating logs from different offsets requires a common time basis. Text sorting is safe only under a much narrower normalized-format contract.","repair":"Parse each explicit offset and compare UTC instants, preserving input order for equal instants.","root_cause":"Timestamp text or timezone-stripped wall time is treated as the ordering key.","sha256":"0448bf1e33ccbf1d1bbcba01499cd1a18b8a424ce15e4971ebd210853d6787b4","title":"Sorting local timestamp text reverses the order of absolute instants · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":35.156,"exit_code":1,"observations":[{"actual":["utc","east"],"check":"positive offset reverses wall-clock order","expected":["east","utc"],"passed":false},{"actual":["west","utc"],"check":"negative offset reverses wall-clock order","expected":["utc","west"],"passed":false},{"actual":["second","first"],"check":"equal instants keep input order","expected":["first","second"],"passed":false},{"actual":["same-utc-day","next-local-day"],"check":"offset crosses calendar date","expected":["next-local-day","same-utc-day"],"passed":false},{"actual":["earlier","later"],"check":"fractional seconds retain order","expected":["earlier","later"],"passed":true},{"actual":["only"],"check":"single record","expected":["only"],"passed":true},{"actual":[],"check":"no records","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"positive offset reverses wall-clock order\", \"actual\": [\"utc\", \"east\"], \"expected\": [\"east\", \"utc\"], \"passed\": false}, {\"check\": \"negative offset reverses wall-clock order\", \"actual\": [\"west\", \"utc\"], \"expected\": [\"utc\", \"west\"], \"passed\": false}, {\"check\": \"equal instants keep input order\", \"actual\": [\"second\", \"first\"], \"expected\": [\"first\", \"second\"], \"passed\": false}, {\"check\": \"offset crosses calendar date\", \"actual\": [\"same-utc-day\", \"next-local-day\"], \"expected\": [\"next-local-day\", \"same-utc-day\"], \"passed\": false}, {\"check\": \"fractional seconds retain order\", \"actual\": [\"earlier\", \"later\"], \"expected\": [\"earlier\", \"later\"], \"passed\": true}, {\"check\": \"single record\", \"actual\": [\"only\"], \"expected\": [\"only\"], \"passed\": true}, {\"check\": \"no records\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":34.412,"exit_code":1,"observations":[{"actual":["utc","east"],"check":"positive offset reverses wall-clock order","expected":["east","utc"],"passed":false},{"actual":["west","utc"],"check":"negative offset reverses wall-clock order","expected":["utc","west"],"passed":false},{"actual":["second","first"],"check":"equal instants keep input order","expected":["first","second"],"passed":false},{"actual":["same-utc-day","next-local-day"],"check":"offset crosses calendar date","expected":["next-local-day","same-utc-day"],"passed":false},{"actual":["earlier","later"],"check":"fractional seconds retain order","expected":["earlier","later"],"passed":true},{"actual":["only"],"check":"single record","expected":["only"],"passed":true},{"actual":[],"check":"no records","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"positive offset reverses wall-clock order\", \"actual\": [\"utc\", \"east\"], \"expected\": [\"east\", \"utc\"], \"passed\": false}, {\"check\": \"negative offset reverses wall-clock order\", \"actual\": [\"west\", \"utc\"], \"expected\": [\"utc\", \"west\"], \"passed\": false}, {\"check\": \"equal instants keep input order\", \"actual\": [\"second\", \"first\"], \"expected\": [\"first\", \"second\"], \"passed\": false}, {\"check\": \"offset crosses calendar date\", \"actual\": [\"same-utc-day\", \"next-local-day\"], \"expected\": [\"next-local-day\", \"same-utc-day\"], \"passed\": false}, {\"check\": \"fractional seconds retain order\", \"actual\": [\"earlier\", \"later\"], \"expected\": [\"earlier\", \"later\"], \"passed\": true}, {\"check\": \"single record\", \"actual\": [\"only\"], \"expected\": [\"only\"], \"passed\": true}, {\"check\": \"no records\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":35.904,"exit_code":0,"observations":[{"actual":["east","utc"],"check":"positive offset reverses wall-clock order","expected":["east","utc"],"passed":true},{"actual":["utc","west"],"check":"negative offset reverses wall-clock order","expected":["utc","west"],"passed":true},{"actual":["first","second"],"check":"equal instants keep input order","expected":["first","second"],"passed":true},{"actual":["next-local-day","same-utc-day"],"check":"offset crosses calendar date","expected":["next-local-day","same-utc-day"],"passed":true},{"actual":["earlier","later"],"check":"fractional seconds retain order","expected":["earlier","later"],"passed":true},{"actual":["only"],"check":"single record","expected":["only"],"passed":true},{"actual":[],"check":"no records","expected":[],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"positive offset reverses wall-clock order\", \"actual\": [\"east\", \"utc\"], \"expected\": [\"east\", \"utc\"], \"passed\": true}, {\"check\": \"negative offset reverses wall-clock order\", \"actual\": [\"utc\", \"west\"], \"expected\": [\"utc\", \"west\"], \"passed\": true}, {\"check\": \"equal instants keep input order\", \"actual\": [\"first\", \"second\"], \"expected\": [\"first\", \"second\"], \"passed\": true}, {\"check\": \"offset crosses calendar date\", \"actual\": [\"next-local-day\", \"same-utc-day\"], \"expected\": [\"next-local-day\", \"same-utc-day\"], \"passed\": true}, {\"check\": \"fractional seconds retain order\", \"actual\": [\"earlier\", \"later\"], \"expected\": [\"earlier\", \"later\"], \"passed\": true}, {\"check\": \"single record\", \"actual\": [\"only\"], \"expected\": [\"only\"], \"passed\": true}, {\"check\": \"no records\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}