{"abstract":"sub-threshold rating gaps are accepted.","category":"Preference pair construction","checks":6,"contract":"Rows are [chosen,rejected,chosen_score,rejected_score]. Return endpoints only when the gap is at least margin.","contract_signature":"rows, margin","evaluation_group":"preference-margin-threshold","failed_approach":"Using a strict greater-than comparison incorrectly rejects a gap exactly at the margin.","family":"w3-preference-pair-construction-margin-threshold","id":"FA-100071","implementations":{"attempt":{"sha256":"21df564e0da17b152731fd3c8f72489ffcfe05bf85df81f0f67cb260319161c1","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(rows, margin):\n    return [[r[0],r[1]] for r in rows if r[2]-r[3]>margin]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('below margin',solve([['a','b',N+1,N]],2),[])\ncheck('exact margin',solve([['a','b',N+2,N]],2),[['a','b']])\ncheck('above margin',solve([['a','b',N+3,N]],2),[['a','b']])\ncheck('tie',solve([['a','b',N,N]],1),[])\ncheck('empty',solve([],N),[])\ncheck('zero margin strict preference',solve([['a','b',1,0]],0),[['a','b']])\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":"137330ef27d97a5475393454c0dfde8ce6aa8a8e2c84f8a7cd4b7f7a2e38ed0d","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(rows, margin):\n    return [[r[0],r[1]] for r in rows if r[2]>r[3]]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('below margin',solve([['a','b',N+1,N]],2),[])\ncheck('exact margin',solve([['a','b',N+2,N]],2),[['a','b']])\ncheck('above margin',solve([['a','b',N+3,N]],2),[['a','b']])\ncheck('tie',solve([['a','b',N,N]],1),[])\ncheck('empty',solve([],N),[])\ncheck('zero margin strict preference',solve([['a','b',1,0]],0),[['a','b']])\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":"These are explicit toy record contracts; they do not claim compatibility with a trainer or improved model behavior. 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-preference-pair-construction-margin-threshold","generated_at":"2026-09-30T16:48:31.261611+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A small deterministic preference-data transform makes pair semantics inspectable without a training framework.","root_cause":"Any positive rating difference is accepted even when the task requires a minimum margin.","sha256":"89d32634eb69c9378462b947cf32419c69cc8cc1283ef1316be56c4f9806820b","title":"Preference pairs: sub-threshold rating gaps are accepted · 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":28.78,"exit_code":1,"observations":[{"actual":[],"check":"below margin","expected":[],"passed":true},{"actual":[],"check":"exact margin","expected":[["a","b"]],"passed":false},{"actual":[["a","b"]],"check":"above margin","expected":[["a","b"]],"passed":true},{"actual":[],"check":"tie","expected":[],"passed":true},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":[["a","b"]],"check":"zero margin strict preference","expected":[["a","b"]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"below margin\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"exact margin\", \"actual\": [], \"expected\": [[\"a\", \"b\"]], \"passed\": false}, {\"check\": \"above margin\", \"actual\": [[\"a\", \"b\"]], \"expected\": [[\"a\", \"b\"]], \"passed\": true}, {\"check\": \"tie\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"zero margin strict preference\", \"actual\": [[\"a\", \"b\"]], \"expected\": [[\"a\", \"b\"]], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":27.348,"exit_code":1,"observations":[{"actual":[["a","b"]],"check":"below margin","expected":[],"passed":false},{"actual":[["a","b"]],"check":"exact margin","expected":[["a","b"]],"passed":true},{"actual":[["a","b"]],"check":"above margin","expected":[["a","b"]],"passed":true},{"actual":[],"check":"tie","expected":[],"passed":true},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":[["a","b"]],"check":"zero margin strict preference","expected":[["a","b"]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"below margin\", \"actual\": [[\"a\", \"b\"]], \"expected\": [], \"passed\": false}, {\"check\": \"exact margin\", \"actual\": [[\"a\", \"b\"]], \"expected\": [[\"a\", \"b\"]], \"passed\": true}, {\"check\": \"above margin\", \"actual\": [[\"a\", \"b\"]], \"expected\": [[\"a\", \"b\"]], \"passed\": true}, {\"check\": \"tie\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"zero margin strict preference\", \"actual\": [[\"a\", \"b\"]], \"expected\": [[\"a\", \"b\"]], \"passed\": true}], \"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."}}