{"abstract":"pair text budget is consumed by the first endpoint.","category":"Preference pair construction","checks":6,"contract":"Rows are [chosen,rejected]. Truncate each endpoint independently to the first limit characters; limit is nonnegative.","contract_signature":"rows, limit","evaluation_group":"preference-length-budget-endpoints","failed_approach":"Splitting the total budget in half truncates short chosen texts unnecessarily.","family":"w3-preference-pair-construction-length-budget-endpoints","id":"FA-100136","implementations":{"attempt":{"sha256":"dc5f1c6d2e064d2be7e01907b5e142e7000af0918a128c09f8e3e6b24638e208","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(rows, limit):\n    return [[r[0][:limit//2],r[1][:limit//2]] for r in rows]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('full budget each',solve([['chosen','rejected']],4),[['chos','reje']])\ncheck('zero budget',solve([['abc','xyz']],0),[['','']])\ncheck('empty rows',solve([],N),[])\ncheck('short text',solve([['a','xy']],5),[['a','xy']])\ncheck('empty rejected',solve([['abc','']],2),[['ab','']])\ncheck('exact boundary',solve([['abcd','wxyz']],4),[['abcd','wxyz']])\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":"38983b3beaf43730140cff8a2ac37f22fef5f189ef15dd960686d771ae585a2c","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(rows, limit):\n    return [[(r[0]+r[1])[:limit],(r[0]+r[1])[limit:2*limit]] for r in rows]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('full budget each',solve([['chosen','rejected']],4),[['chos','reje']])\ncheck('zero budget',solve([['abc','xyz']],0),[['','']])\ncheck('empty rows',solve([],N),[])\ncheck('short text',solve([['a','xy']],5),[['a','xy']])\ncheck('empty rejected',solve([['abc','']],2),[['ab','']])\ncheck('exact boundary',solve([['abcd','wxyz']],4),[['abcd','wxyz']])\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-length-budget-endpoints","generated_at":"2026-09-30T16:48:32.170476+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":"A shared truncation cursor leaves the rejected endpoint with only unused remainder.","sha256":"c447f95085a7ddab47c0db5a791fb059ff20bc2b473d8942b7d3240594256805","title":"Preference pairs: pair text budget is consumed by the first endpoint · 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":29.584,"exit_code":1,"observations":[{"actual":[["ch","re"]],"check":"full budget each","expected":[["chos","reje"]],"passed":false},{"actual":[["",""]],"check":"zero budget","expected":[["",""]],"passed":true},{"actual":[],"check":"empty rows","expected":[],"passed":true},{"actual":[["a","xy"]],"check":"short text","expected":[["a","xy"]],"passed":true},{"actual":[["a",""]],"check":"empty rejected","expected":[["ab",""]],"passed":false},{"actual":[["ab","wx"]],"check":"exact boundary","expected":[["abcd","wxyz"]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"full budget each\", \"actual\": [[\"ch\", \"re\"]], \"expected\": [[\"chos\", \"reje\"]], \"passed\": false}, {\"check\": \"zero budget\", \"actual\": [[\"\", \"\"]], \"expected\": [[\"\", \"\"]], \"passed\": true}, {\"check\": \"empty rows\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"short text\", \"actual\": [[\"a\", \"xy\"]], \"expected\": [[\"a\", \"xy\"]], \"passed\": true}, {\"check\": \"empty rejected\", \"actual\": [[\"a\", \"\"]], \"expected\": [[\"ab\", \"\"]], \"passed\": false}, {\"check\": \"exact boundary\", \"actual\": [[\"ab\", \"wx\"]], \"expected\": [[\"abcd\", \"wxyz\"]], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":29.551,"exit_code":1,"observations":[{"actual":[["chos","enre"]],"check":"full budget each","expected":[["chos","reje"]],"passed":false},{"actual":[["",""]],"check":"zero budget","expected":[["",""]],"passed":true},{"actual":[],"check":"empty rows","expected":[],"passed":true},{"actual":[["axy",""]],"check":"short text","expected":[["a","xy"]],"passed":false},{"actual":[["ab","c"]],"check":"empty rejected","expected":[["ab",""]],"passed":false},{"actual":[["abcd","wxyz"]],"check":"exact boundary","expected":[["abcd","wxyz"]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"full budget each\", \"actual\": [[\"chos\", \"enre\"]], \"expected\": [[\"chos\", \"reje\"]], \"passed\": false}, {\"check\": \"zero budget\", \"actual\": [[\"\", \"\"]], \"expected\": [[\"\", \"\"]], \"passed\": true}, {\"check\": \"empty rows\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"short text\", \"actual\": [[\"axy\", \"\"]], \"expected\": [[\"a\", \"xy\"]], \"passed\": false}, {\"check\": \"empty rejected\", \"actual\": [[\"ab\", \"c\"]], \"expected\": [[\"ab\", \"\"]], \"passed\": false}, {\"check\": \"exact boundary\", \"actual\": [[\"abcd\", \"wxyz\"]], \"expected\": [[\"abcd\", \"wxyz\"]], \"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."}}