{"abstract":"Quality switching leaves obsolete old-rendition downloads queued.","category":"Streaming segment lifecycle","checks":4,"contract":"Pending entries are [rendition,sequence]. A switch replaces only pending work from the old rendition; unrelated audio/track work remains.","contract_signature":"pending, old_rendition, replacement","evaluation_group":"xmed-rendition-switch-discards-old-pending","failed_approach":"Replacing the entire queue cancels unrelated media tracks.","family":"xmed-rendition-switch-discards-old-pending","id":"FA-11191","implementations":{"attempt":{"sha256":"4a6ed85f757056cece18aff8ef6c37565caace664681ed379acc120959cda78b","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(pending, old_rendition, replacement):\n    return list(replacement)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([['low', 1], ['audio', 1]], 'low', [['high', 1]])),[['audio', 1], ['high', 1]])\ncheck('fixture 2',solve(*([['low', 1]], 'low', [])),[])\ncheck('fixture 3',solve(*([], 'low', [['high', 2]])),[['high', 2]])\ncheck('fixture 4',solve(*([['audio', 2]], 'low', [])),[['audio', 2]])\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":"b3aacd901cea02660e23ee7561860397d94a121db63ad1280e138f5300c9fbf0","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(pending, old_rendition, replacement):\n    return list(pending)+list(replacement)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([['low', 1], ['audio', 1]], 'low', [['high', 1]])),[['audio', 1], ['high', 1]])\ncheck('fixture 2',solve(*([['low', 1]], 'low', [])),[])\ncheck('fixture 3',solve(*([], 'low', [['high', 2]])),[['high', 2]])\ncheck('fixture 4',solve(*([['audio', 2]], 'low', [])),[['audio', 2]])\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-rendition-switch-discards-old-pending","generated_at":"2026-09-29T14:38:45.683577+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":"Quality switching leaves obsolete old-rendition downloads queued.","sha256":"ccb3e42f0898ce6078d10aa698d1227386bfe6615daf0d404803ecb6da80abfa","title":"Rendition switch discards old pending · 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":37.826,"exit_code":1,"observations":[{"actual":[["high",1]],"check":"fixture 1","expected":[["audio",1],["high",1]],"passed":false},{"actual":[],"check":"fixture 2","expected":[],"passed":true},{"actual":[["high",2]],"check":"fixture 3","expected":[["high",2]],"passed":true},{"actual":[],"check":"fixture 4","expected":[["audio",2]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [[\"high\", 1]], \"expected\": [[\"audio\", 1], [\"high\", 1]], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [[\"high\", 2]], \"expected\": [[\"high\", 2]], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [], \"expected\": [[\"audio\", 2]], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.5,"exit_code":1,"observations":[{"actual":[["low",1],["audio",1],["high",1]],"check":"fixture 1","expected":[["audio",1],["high",1]],"passed":false},{"actual":[["low",1]],"check":"fixture 2","expected":[],"passed":false},{"actual":[["high",2]],"check":"fixture 3","expected":[["high",2]],"passed":true},{"actual":[["audio",2]],"check":"fixture 4","expected":[["audio",2]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [[\"low\", 1], [\"audio\", 1], [\"high\", 1]], \"expected\": [[\"audio\", 1], [\"high\", 1]], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [[\"low\", 1]], \"expected\": [], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [[\"high\", 2]], \"expected\": [[\"high\", 2]], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [[\"audio\", 2]], \"expected\": [[\"audio\", 2]], \"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."}}