{"abstract":"A class-column reorder silently relabels target vectors.","category":"Training label alignment","checks":7,"contract":"Project each score row from source_classes order to target_classes order by class name; missing target classes receive 0.","contract_signature":"scores, source_classes, target_classes","evaluation_group":"training-label-alignment-named-score-column-projection","failed_approach":"Copying the first columns to the new vector width preserves shape but changes class meaning.","family":"w3-training-label-alignment-class-column-projection","id":"FA-97961","implementations":{"attempt":{"sha256":"57416a63e3b9bf18924a9da1e472f24fa5d840d902863f19010c18f4a36d8378","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(scores, source_classes, target_classes):\n    return [row+[0]*max(0,len(target_classes)-len(row)) for row in scores]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('swap named columns',solve([[N,N+1]],['cat','dog'],['dog','cat']),[[N+1,N]])\ncheck('new class zero',solve([[2,3]],['a','b'],['c','a']),[[0,2]])\ncheck('empty rows',solve([],['a'],['a','b']),[])\ncheck('single retained class',solve([[N]],['x'],['x']),[[N]])\ncheck('drop extra class',solve([[1,2,3]],['a','b','c'],['c']),[[3]])\ncheck('empty targets',solve([[1]],['a'],[]),[[]])\ncheck('multiple rows',solve([[1,2],[3,4]],['x','y'],['y']),[[2],[4]])\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":"4f601a3e9c88d1d6c6f98c3a448eb21378b546fbbb28f80a52095f35cc2d78d0","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(scores, source_classes, target_classes):\n    return [row[:len(target_classes)] for row in scores]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('swap named columns',solve([[N,N+1]],['cat','dog'],['dog','cat']),[[N+1,N]])\ncheck('new class zero',solve([[2,3]],['a','b'],['c','a']),[[0,2]])\ncheck('empty rows',solve([],['a'],['a','b']),[])\ncheck('single retained class',solve([[N]],['x'],['x']),[[N]])\ncheck('drop extra class',solve([[1,2,3]],['a','b','c'],['c']),[[3]])\ncheck('empty targets',solve([[1]],['a'],[]),[[]])\ncheck('multiple rows',solve([[1,2],[3,4]],['x','y'],['y']),[[2],[4]])\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":"Class names are unique; each score row matches source_classes width. 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-training-label-alignment-class-column-projection","generated_at":"2026-09-30T16:48:07.975853+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A small deterministic training-data operation makes label ownership and ordering explicit.","root_cause":"Scores are projected using numeric offsets while the destination class names have another order.","sha256":"e2b1adf8d2ca301b9ffec151e58cba2ef1b2e1c34c87c3659c5bc3b64aab917e","title":"A class-column reorder silently relabels target vectors · 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":26.913,"exit_code":1,"observations":[{"actual":[[1,2]],"check":"swap named columns","expected":[[2,1]],"passed":false},{"actual":[[2,3]],"check":"new class zero","expected":[[0,2]],"passed":false},{"actual":[],"check":"empty rows","expected":[],"passed":true},{"actual":[[1]],"check":"single retained class","expected":[[1]],"passed":true},{"actual":[[1,2,3]],"check":"drop extra class","expected":[[3]],"passed":false},{"actual":[[1]],"check":"empty targets","expected":[[]],"passed":false},{"actual":[[1,2],[3,4]],"check":"multiple rows","expected":[[2],[4]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"swap named columns\", \"actual\": [[1, 2]], \"expected\": [[2, 1]], \"passed\": false}, {\"check\": \"new class zero\", \"actual\": [[2, 3]], \"expected\": [[0, 2]], \"passed\": false}, {\"check\": \"empty rows\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"single retained class\", \"actual\": [[1]], \"expected\": [[1]], \"passed\": true}, {\"check\": \"drop extra class\", \"actual\": [[1, 2, 3]], \"expected\": [[3]], \"passed\": false}, {\"check\": \"empty targets\", \"actual\": [[1]], \"expected\": [[]], \"passed\": false}, {\"check\": \"multiple rows\", \"actual\": [[1, 2], [3, 4]], \"expected\": [[2], [4]], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":26.181,"exit_code":1,"observations":[{"actual":[[1,2]],"check":"swap named columns","expected":[[2,1]],"passed":false},{"actual":[[2,3]],"check":"new class zero","expected":[[0,2]],"passed":false},{"actual":[],"check":"empty rows","expected":[],"passed":true},{"actual":[[1]],"check":"single retained class","expected":[[1]],"passed":true},{"actual":[[1]],"check":"drop extra class","expected":[[3]],"passed":false},{"actual":[[]],"check":"empty targets","expected":[[]],"passed":true},{"actual":[[1],[3]],"check":"multiple rows","expected":[[2],[4]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"swap named columns\", \"actual\": [[1, 2]], \"expected\": [[2, 1]], \"passed\": false}, {\"check\": \"new class zero\", \"actual\": [[2, 3]], \"expected\": [[0, 2]], \"passed\": false}, {\"check\": \"empty rows\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"single retained class\", \"actual\": [[1]], \"expected\": [[1]], \"passed\": true}, {\"check\": \"drop extra class\", \"actual\": [[1]], \"expected\": [[3]], \"passed\": false}, {\"check\": \"empty targets\", \"actual\": [[]], \"expected\": [[]], \"passed\": true}, {\"check\": \"multiple rows\", \"actual\": [[1], [3]], \"expected\": [[2], [4]], \"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."}}