{"abstract":"Live playback starts at the unstable edge instead of behind the holdback.","category":"Media timeline seeking","checks":4,"contract":"For this contiguous live-window policy, return latest end minus nonnegative holdback clamped to earliest start; empty ranges return None. No gap correction is included.","contract_signature":"ranges, holdback","evaluation_group":"xmed-live-edge-minus-holdback","failed_approach":"Unclamped holdback can select a time before retained media.","family":"xmed-live-edge-minus-holdback","id":"FA-11236","implementations":{"attempt":{"sha256":"a9a90a966daec0e54483490779f015964c201efab98235d154032bfdb12121d5","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(ranges, holdback):\n    return ranges[-1][1]-holdback 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(*([[10, 20]], 3)),17)\ncheck('fixture 2',solve(*([[10, 20]], 30)),10)\ncheck('fixture 3',solve(*([], 3)),None)\ncheck('fixture 4',solve(*([[0, 10]], 0)),10)\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":"1665b45824e62a89bcfdeeb67798f2922ffa25e32dce861b2b2305e7ccc37fd2","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(ranges, holdback):\n    return ranges[-1][1] 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(*([[10, 20]], 3)),17)\ncheck('fixture 2',solve(*([[10, 20]], 30)),10)\ncheck('fixture 3',solve(*([], 3)),None)\ncheck('fixture 4',solve(*([[0, 10]], 0)),10)\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-live-edge-minus-holdback","generated_at":"2026-09-29T14:38:46.174693+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.","root_cause":"Live playback starts at the unstable edge instead of behind the holdback.","sha256":"1e8ec67bcde7aeb8194cdec52b79c4a72056514ce3bc6f7892b20fe57834ca99","title":"Live edge minus holdback · case 01","variant":1,"variant_policy":"The five numbered cases rerun the same authored boundary fixtures; they are reproducibility runs, not independent input variants.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":38.235,"exit_code":1,"observations":[{"actual":17,"check":"fixture 1","expected":17,"passed":true},{"actual":-10,"check":"fixture 2","expected":10,"passed":false},{"actual":null,"check":"fixture 3","expected":null,"passed":true},{"actual":10,"check":"fixture 4","expected":10,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": 17, \"expected\": 17, \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": -10, \"expected\": 10, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 10, \"expected\": 10, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":37.441,"exit_code":1,"observations":[{"actual":20,"check":"fixture 1","expected":17,"passed":false},{"actual":20,"check":"fixture 2","expected":10,"passed":false},{"actual":null,"check":"fixture 3","expected":null,"passed":true},{"actual":10,"check":"fixture 4","expected":10,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": 20, \"expected\": 17, \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": 20, \"expected\": 10, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 10, \"expected\": 10, \"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."}}