{"abstract":"Citation starts before the retained window.","category":"Chunk citation alignment","checks":6,"contract":"Given window [b,b+L) and citation [s,e), return their half-open intersection or None for empty intersection.","contract_signature":"base, span, length","evaluation_group":"w3-cca-truncate_start","failed_approach":"Moving an earlier start to the window boundary but retaining the old end leaks text beyond the window.","family":"w3-chunk-citation-alignment-truncate-start","id":"FA-99656","implementations":{"attempt":{"sha256":"1c4c83f6fee96f835d14891bbd89cb8feb18e099577e51163d47830a1a8fe50f","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(base, span, length):\n    s,e=span\n    return [max(s,base),e] if e>base else None\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('clip left and right',solve(N,[N-3,N+8],5),[N,N+5])\ncheck('inside window',solve(N,[N+1,N+3],5),[N+1,N+3])\ncheck('before window',solve(N,[N-4,N-1],5),None)\ncheck('after window',solve(N,[N+6,N+8],5),None)\ncheck('touch edge',solve(N,[N-2,N],5),None)\ncheck('zero window',solve(N,[N,N+1],0),None)\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":"fa86c6e327f0802417d9eaec3188a495ff541825fbb6eac53f5aaaa18c7e09f4","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(base, span, length):\n    s,e=span\n    return [s,e]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('clip left and right',solve(N,[N-3,N+8],5),[N,N+5])\ncheck('inside window',solve(N,[N+1,N+3],5),[N+1,N+3])\ncheck('before window',solve(N,[N-4,N-1],5),None)\ncheck('after window',solve(N,[N+6,N+8],5),None)\ncheck('touch edge',solve(N,[N-2,N],5),None)\ncheck('zero window',solve(N,[N,N+1],0),None)\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-truncate-start","generated_at":"2026-09-30T16:48:26.712091+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":"The clipped excerpt start is not applied to citations.","sha256":"b10903eb1809cbf96fd32d7b8328cef9005eb6bffbdd2998302b47ac8ed1efba","title":"Citation starts before the retained window · 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":27.113,"exit_code":1,"observations":[{"actual":[1,9],"check":"clip left and right","expected":[1,6],"passed":false},{"actual":[2,4],"check":"inside window","expected":[2,4],"passed":true},{"actual":null,"check":"before window","expected":null,"passed":true},{"actual":[7,9],"check":"after window","expected":null,"passed":false},{"actual":null,"check":"touch edge","expected":null,"passed":true},{"actual":[1,2],"check":"zero window","expected":null,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"clip left and right\", \"actual\": [1, 9], \"expected\": [1, 6], \"passed\": false}, {\"check\": \"inside window\", \"actual\": [2, 4], \"expected\": [2, 4], \"passed\": true}, {\"check\": \"before window\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"after window\", \"actual\": [7, 9], \"expected\": null, \"passed\": false}, {\"check\": \"touch edge\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"zero window\", \"actual\": [1, 2], \"expected\": null, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":27.057,"exit_code":1,"observations":[{"actual":[-2,9],"check":"clip left and right","expected":[1,6],"passed":false},{"actual":[2,4],"check":"inside window","expected":[2,4],"passed":true},{"actual":[-3,0],"check":"before window","expected":null,"passed":false},{"actual":[7,9],"check":"after window","expected":null,"passed":false},{"actual":[-1,1],"check":"touch edge","expected":null,"passed":false},{"actual":[1,2],"check":"zero window","expected":null,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"clip left and right\", \"actual\": [-2, 9], \"expected\": [1, 6], \"passed\": false}, {\"check\": \"inside window\", \"actual\": [2, 4], \"expected\": [2, 4], \"passed\": true}, {\"check\": \"before window\", \"actual\": [-3, 0], \"expected\": null, \"passed\": false}, {\"check\": \"after window\", \"actual\": [7, 9], \"expected\": null, \"passed\": false}, {\"check\": \"touch edge\", \"actual\": [-1, 1], \"expected\": null, \"passed\": false}, {\"check\": \"zero window\", \"actual\": [1, 2], \"expected\": null, \"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."}}