{"abstract":"equal event times follow input order instead of record ID order.","category":"Dataset split isolation","checks":7,"contract":"Rows [id,time] have unique string IDs; return IDs in chronological order, breaking time ties by full lexical ID.","contract_signature":"rows","evaluation_group":"ds-timestamp-tie","failed_approach":"Comparing only the first character of each ID leaves same-prefix ties in input order.","family":"w3-dataset-split-isolation-timestamp-tie-break","id":"FA-97901","implementations":{"attempt":{"sha256":"2a03c83bd89ef3d2a8e6943e840c2a7b3f64dc5ff712aae752542ca5ed5da080","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(rows):\n    return [i for i,t in sorted(rows,key=lambda r:(r[1],r[0][0]))]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('tie order',solve([['b',N],['a',N]]),['a','b'])\ncheck('chronology',solve([['b',N+1],['a',N]]),['a','b'])\ncheck('empty',solve([]),[])\ncheck('singleton',solve([['x',N]]),['x'])\ncheck('mixed ties',solve([['c',N+1],['b',N],['a',N]]),['a','b','c'])\ncheck('same prefix ties',solve([['ay',N],['ax',N]]),['ax','ay'])\ncheck('duplicate times',solve([['z',0],['a',0],['m',0]]),['a','m','z'])\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":"e65a5c58ed0a739587822bdae61dee20beaf7ab0d05b888a295090236f003dde","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(rows):\n    return [i for i,t in sorted(rows,key=lambda r:r[1])]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('tie order',solve([['b',N],['a',N]]),['a','b'])\ncheck('chronology',solve([['b',N+1],['a',N]]),['a','b'])\ncheck('empty',solve([]),[])\ncheck('singleton',solve([['x',N]]),['x'])\ncheck('mixed ties',solve([['c',N+1],['b',N],['a',N]]),['a','b','c'])\ncheck('same prefix ties',solve([['ay',N],['ax',N]]),['ax','ay'])\ncheck('duplicate times',solve([['z',0],['a',0],['m',0]]),['a','m','z'])\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":"Inputs are small in-memory records with self-contained contracts; no claim is made about production sampling quality. 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":"w3-dataset-split-isolation-timestamp-tie-break","generated_at":"2026-09-30T16:48:07.116958+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This toy split allocator makes membership rules explicit for reproducible evaluation fixtures.","root_cause":"Sorting only by timestamp preserves the incoming order for equal-time records, so the tie rule is not based on ID.","sha256":"3ca9fa36c2bcd8cf116bd5f11722df939329bfffe2e064c97d9009fe5552ee5f","title":"Dataset split: equal event times follow input order instead of record ID order · case 01","variant":1,"variant_policy":"The fixture code references N, supplied as 1 through 5. Fixed boundary checks may repeat. These records share one mechanism and must remain together in evaluation splits.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":27.548,"exit_code":1,"observations":[{"actual":["a","b"],"check":"tie order","expected":["a","b"],"passed":true},{"actual":["a","b"],"check":"chronology","expected":["a","b"],"passed":true},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":["x"],"check":"singleton","expected":["x"],"passed":true},{"actual":["a","b","c"],"check":"mixed ties","expected":["a","b","c"],"passed":true},{"actual":["ay","ax"],"check":"same prefix ties","expected":["ax","ay"],"passed":false},{"actual":["a","m","z"],"check":"duplicate times","expected":["a","m","z"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"tie order\", \"actual\": [\"a\", \"b\"], \"expected\": [\"a\", \"b\"], \"passed\": true}, {\"check\": \"chronology\", \"actual\": [\"a\", \"b\"], \"expected\": [\"a\", \"b\"], \"passed\": true}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"singleton\", \"actual\": [\"x\"], \"expected\": [\"x\"], \"passed\": true}, {\"check\": \"mixed ties\", \"actual\": [\"a\", \"b\", \"c\"], \"expected\": [\"a\", \"b\", \"c\"], \"passed\": true}, {\"check\": \"same prefix ties\", \"actual\": [\"ay\", \"ax\"], \"expected\": [\"ax\", \"ay\"], \"passed\": false}, {\"check\": \"duplicate times\", \"actual\": [\"a\", \"m\", \"z\"], \"expected\": [\"a\", \"m\", \"z\"], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":26.821,"exit_code":1,"observations":[{"actual":["b","a"],"check":"tie order","expected":["a","b"],"passed":false},{"actual":["a","b"],"check":"chronology","expected":["a","b"],"passed":true},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":["x"],"check":"singleton","expected":["x"],"passed":true},{"actual":["b","a","c"],"check":"mixed ties","expected":["a","b","c"],"passed":false},{"actual":["ay","ax"],"check":"same prefix ties","expected":["ax","ay"],"passed":false},{"actual":["z","a","m"],"check":"duplicate times","expected":["a","m","z"],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"tie order\", \"actual\": [\"b\", \"a\"], \"expected\": [\"a\", \"b\"], \"passed\": false}, {\"check\": \"chronology\", \"actual\": [\"a\", \"b\"], \"expected\": [\"a\", \"b\"], \"passed\": true}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"singleton\", \"actual\": [\"x\"], \"expected\": [\"x\"], \"passed\": true}, {\"check\": \"mixed ties\", \"actual\": [\"b\", \"a\", \"c\"], \"expected\": [\"a\", \"b\", \"c\"], \"passed\": false}, {\"check\": \"same prefix ties\", \"actual\": [\"ay\", \"ax\"], \"expected\": [\"ax\", \"ay\"], \"passed\": false}, {\"check\": \"duplicate times\", \"actual\": [\"z\", \"a\", \"m\"], \"expected\": [\"a\", \"m\", \"z\"], \"passed\": false}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}