{"abstract":"Merged chunk offsets ignore inserted separator lengths.","category":"Chunk citation alignment","checks":6,"contract":"Given chunk lengths and a constant separator length, return each chunk start in the joined text; no leading separator.","contract_signature":"lengths, separator","evaluation_group":"w3-cca-prefix_sum","failed_approach":"Adding one separator per chunk also counts a nonexistent separator before the first chunk.","family":"w3-chunk-citation-alignment-offset-prefix-sum","id":"FA-99701","implementations":{"attempt":{"sha256":"7129b38fdb1ed2ee4d99850c4736dc34673256bc7708678ead73586b47d90b81","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(lengths, separator):\n    starts=[]\n    pos=0\n    for length in lengths:\n     pos+=separator\n     starts.append(pos)\n     pos+=length\n    return starts\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('two chunks',solve([N,3],2),[0,N+2])\ncheck('three chunks',solve([1,2,3],1),[0,2,5])\ncheck('empty',solve([],4),[])\ncheck('one chunk',solve([N],5),[0])\ncheck('zero separator',solve([2,4],0),[0,2])\ncheck('zero length chunk',solve([0,2],3),[0,3])\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":"e25e1f09e70df2c685f579aa1e43f5e15e0a81ded7ccc6ef5b45324f529077cb","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(lengths, separator):\n    starts=[]\n    pos=0\n    for length in lengths:\n     starts.append(pos)\n     pos+=length\n    return starts\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('two chunks',solve([N,3],2),[0,N+2])\ncheck('three chunks',solve([1,2,3],1),[0,2,5])\ncheck('empty',solve([],4),[])\ncheck('one chunk',solve([N],5),[0])\ncheck('zero separator',solve([2,4],0),[0,2])\ncheck('zero length chunk',solve([0,2],3),[0,3])\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-offset-prefix-sum","generated_at":"2026-09-30T16:48:27.159076+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":"Chunk starts are accumulated using content lengths alone.","sha256":"d641ba27c7c654081453cba5c99698dcd261b734e3cf1ef07750ea8c31cf3785","title":"Merged chunk offsets ignore inserted separator lengths · 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":28.483,"exit_code":1,"observations":[{"actual":[2,5],"check":"two chunks","expected":[0,3],"passed":false},{"actual":[1,3,6],"check":"three chunks","expected":[0,2,5],"passed":false},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":[5],"check":"one chunk","expected":[0],"passed":false},{"actual":[0,2],"check":"zero separator","expected":[0,2],"passed":true},{"actual":[3,6],"check":"zero length chunk","expected":[0,3],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"two chunks\", \"actual\": [2, 5], \"expected\": [0, 3], \"passed\": false}, {\"check\": \"three chunks\", \"actual\": [1, 3, 6], \"expected\": [0, 2, 5], \"passed\": false}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"one chunk\", \"actual\": [5], \"expected\": [0], \"passed\": false}, {\"check\": \"zero separator\", \"actual\": [0, 2], \"expected\": [0, 2], \"passed\": true}, {\"check\": \"zero length chunk\", \"actual\": [3, 6], \"expected\": [0, 3], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":27.779,"exit_code":1,"observations":[{"actual":[0,1],"check":"two chunks","expected":[0,3],"passed":false},{"actual":[0,1,3],"check":"three chunks","expected":[0,2,5],"passed":false},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":[0],"check":"one chunk","expected":[0],"passed":true},{"actual":[0,2],"check":"zero separator","expected":[0,2],"passed":true},{"actual":[0,0],"check":"zero length chunk","expected":[0,3],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"two chunks\", \"actual\": [0, 1], \"expected\": [0, 3], \"passed\": false}, {\"check\": \"three chunks\", \"actual\": [0, 1, 3], \"expected\": [0, 2, 5], \"passed\": false}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"one chunk\", \"actual\": [0], \"expected\": [0], \"passed\": true}, {\"check\": \"zero separator\", \"actual\": [0, 2], \"expected\": [0, 2], \"passed\": true}, {\"check\": \"zero length chunk\", \"actual\": [0, 0], \"expected\": [0, 3], \"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."}}