{"abstract":"A seek is accepted inside an unbuffered gap.","category":"Media timeline seeking","checks":4,"contract":"Ranges are sorted disjoint nonempty half-open buffered intervals. Return target when buffered, otherwise the next range start; return None beyond all data.","evaluation_group":"xmed-seek-buffer-gap-next-available","failed_approach":"Always jumping to range start moves an already-buffered target backward.","family":"xmed-seek-buffer-gap-next-available","id":"FA-11231","implementations":{"attempt":{"sha256":"a1e115d37b2735ddfe7b4e0092ae29e38452ae142767734a4722a1dbab49a598","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(ranges, target):\n    return next((start for start,end in ranges if end>target),None)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([[0, 4], [6, 10]], 5)),6)\ncheck('fixture 2',solve(*([[0, 4], [6, 10]], 2)),2)\ncheck('fixture 3',solve(*([[0, 4]], 4)),None)\ncheck('fixture 4',solve(*([], 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":"dc56322a5ed2442616d23f1e658545ae673a17fe0755b3e7d8a335b8d33a007a","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(ranges, target):\n    return target if ranges else None\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([[0, 4], [6, 10]], 5)),6)\ncheck('fixture 2',solve(*([[0, 4], [6, 10]], 2)),2)\ncheck('fixture 3',solve(*([[0, 4]], 4)),None)\ncheck('fixture 4',solve(*([], 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"},"fixed":{"sha256":"e1d82951241d98feb76c2d5e8c15d24b43a305417963577e0f5f63f5a45816e5","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(ranges, target):\n    return next((max(start,target) for start,end in ranges if end>target),None)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([[0, 4], [6, 10]], 5)),6)\ncheck('fixture 2',solve(*([[0, 4], [6, 10]], 2)),2)\ncheck('fixture 3',solve(*([[0, 4]], 4)),None)\ncheck('fixture 4',solve(*([], 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":" 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":"xmed-seek-buffer-gap-next-available","generated_at":"2026-09-29T14:38:46.135023+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic local media controller stage; metadata and downloaded data are supplied explicitly. No external player, service or codec is required.","repair":"Preserve the media contract: Ranges are sorted disjoint nonempty half-open buffered intervals. Return target when buffered, otherwise the next range start; return None beyond all data.","root_cause":"A seek is accepted inside an unbuffered gap.","sha256":"e6deed4912a458c997c56e30a7ed4cb277f7392a7425baed82760acd8da3995d","title":"Seek buffer gap next available · case 01","variant":1,"variant_policy":"The five numbered cases rerun the same authored boundary fixtures; they are reproducibility runs, not independent input variants.","verification":{"attempt":{"elapsed_ms":39.814,"exit_code":1,"observations":[{"actual":6,"check":"fixture 1","expected":6,"passed":true},{"actual":0,"check":"fixture 2","expected":2,"passed":false},{"actual":null,"check":"fixture 3","expected":null,"passed":true},{"actual":null,"check":"fixture 4","expected":null,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": 6, \"expected\": 6, \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": 0, \"expected\": 2, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": null, \"expected\": null, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":37.236,"exit_code":1,"observations":[{"actual":5,"check":"fixture 1","expected":6,"passed":false},{"actual":2,"check":"fixture 2","expected":2,"passed":true},{"actual":4,"check":"fixture 3","expected":null,"passed":false},{"actual":null,"check":"fixture 4","expected":null,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": 5, \"expected\": 6, \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": 2, \"expected\": 2, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": 4, \"expected\": null, \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": null, \"expected\": null, \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":36.075,"exit_code":0,"observations":[{"actual":6,"check":"fixture 1","expected":6,"passed":true},{"actual":2,"check":"fixture 2","expected":2,"passed":true},{"actual":null,"check":"fixture 3","expected":null,"passed":true},{"actual":null,"check":"fixture 4","expected":null,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": 6, \"expected\": 6, \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": 2, \"expected\": 2, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": null, \"expected\": null, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}