{"abstract":"A citation anchor is assigned to every overlapping chunk.","category":"Chunk citation alignment","checks":6,"contract":"Given chunks [start,end] and citation [s,e), return indices of chunks containing s, selecting the earliest only; chunk containment is start <= s < end.","contract_signature":"chunks, span","evaluation_group":"w3-cca-anchor_owner","failed_approach":"Keeping only chunks that contain the entire span drops valid citations split across chunk boundaries.","family":"w3-chunk-citation-alignment-citation-anchor","id":"FA-99676","implementations":{"attempt":{"sha256":"18ebcdd93a7af0dcac78ec86ab1108f7869405ed0d2af5a850476c0ddf7897de","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(chunks, span):\n    s,e=span\n    return [i for i,(a,b) in enumerate(chunks) if a<=s and e<=b][:1]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('overlap earliest',solve([[0,5],[3,8]],[4,7]),[0])\ncheck('anchor second',solve([[0,2],[2,5]],[2,4]),[1])\ncheck('at end excluded',solve([[0,2]],[2,3]),[])\ncheck('empty chunks',solve([],[0,1]),[])\ncheck('anchor despite tail crossing',solve([[0,3],[3,6]],[2,5]),[0])\ncheck('no containing start',solve([[0,2]],[4,5]),[])\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":"36d9c9083c5fb0ff37b13b338daa2f57b2400fb08d99770d661688bf76a55d54","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(chunks, span):\n    s,e=span\n    return [i for i,(a,b) in enumerate(chunks) if a<e and s<b]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('overlap earliest',solve([[0,5],[3,8]],[4,7]),[0])\ncheck('anchor second',solve([[0,2],[2,5]],[2,4]),[1])\ncheck('at end excluded',solve([[0,2]],[2,3]),[])\ncheck('empty chunks',solve([],[0,1]),[])\ncheck('anchor despite tail crossing',solve([[0,3],[3,6]],[2,5]),[0])\ncheck('no containing start',solve([[0,2]],[4,5]),[])\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 integer offsets and identifiers under the stated toy contract; this does not define a document format or production citation API. 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-chunk-citation-alignment-citation-anchor","generated_at":"2026-09-30T16:48:26.742010+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic citation bookkeeping model isolates source attribution from rendering and retrieval.","root_cause":"Overlap duplicates the same source anchor in stitched output.","sha256":"3786b9810824273e63e3cf5ac90c0b24901da9d1043fa39f4f9809ab2ec76862","title":"A citation anchor is assigned to every overlapping chunk · case 01","variant":1,"variant_policy":"The same explicitly authored fixtures repeat across all five numbered records; runtime N is unused. These records share one mechanism and must remain together in evaluation splits.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":27.198,"exit_code":1,"observations":[{"actual":[1],"check":"overlap earliest","expected":[0],"passed":false},{"actual":[1],"check":"anchor second","expected":[1],"passed":true},{"actual":[],"check":"at end excluded","expected":[],"passed":true},{"actual":[],"check":"empty chunks","expected":[],"passed":true},{"actual":[],"check":"anchor despite tail crossing","expected":[0],"passed":false},{"actual":[],"check":"no containing start","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"overlap earliest\", \"actual\": [1], \"expected\": [0], \"passed\": false}, {\"check\": \"anchor second\", \"actual\": [1], \"expected\": [1], \"passed\": true}, {\"check\": \"at end excluded\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty chunks\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"anchor despite tail crossing\", \"actual\": [], \"expected\": [0], \"passed\": false}, {\"check\": \"no containing start\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":27.264,"exit_code":1,"observations":[{"actual":[0,1],"check":"overlap earliest","expected":[0],"passed":false},{"actual":[1],"check":"anchor second","expected":[1],"passed":true},{"actual":[],"check":"at end excluded","expected":[],"passed":true},{"actual":[],"check":"empty chunks","expected":[],"passed":true},{"actual":[0,1],"check":"anchor despite tail crossing","expected":[0],"passed":false},{"actual":[],"check":"no containing start","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"overlap earliest\", \"actual\": [0, 1], \"expected\": [0], \"passed\": false}, {\"check\": \"anchor second\", \"actual\": [1], \"expected\": [1], \"passed\": true}, {\"check\": \"at end excluded\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty chunks\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"anchor despite tail crossing\", \"actual\": [0, 1], \"expected\": [0], \"passed\": false}, {\"check\": \"no containing start\", \"actual\": [], \"expected\": [], \"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."}}