{"abstract":"Two quality renditions share a sequence number and collide in the segment cache.","category":"Streaming segment lifecycle","checks":4,"contract":"Return the complete local download identity [rendition ID,absolute sequence,optional partial-segment index].","evaluation_group":"xmed-segment-cache-key-includes-rendition","failed_approach":"Adding rendition but omitting part identity collapses distinct partial segments.","family":"xmed-segment-cache-key-includes-rendition","id":"FA-11141","implementations":{"attempt":{"sha256":"4deae4f90f202b8331a905bebb7251920e8c50163998662dcc5f70fe0882672d","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(rendition, sequence, part):\n    return [rendition,sequence]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*('low', 7, 0)),['low', 7, 0])\ncheck('fixture 2',solve(*('high', 7, 0)),['high', 7, 0])\ncheck('fixture 3',solve(*('low', 7, 1)),['low', 7, 1])\ncheck('fixture 4',solve(*('low', 0, None)),['low', 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":"8630be1fb8888467ced251e1b94e5edacf5103106c70a58a2057d4e6cc33a7e4","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(rendition, sequence, part):\n    return [sequence,part]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*('low', 7, 0)),['low', 7, 0])\ncheck('fixture 2',solve(*('high', 7, 0)),['high', 7, 0])\ncheck('fixture 3',solve(*('low', 7, 1)),['low', 7, 1])\ncheck('fixture 4',solve(*('low', 0, None)),['low', 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":"175269b0fb0045c5784640c98ff0046d38707c536d99bd7ec6093f1077b99e70","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(rendition, sequence, part):\n    return [rendition,sequence,part]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*('low', 7, 0)),['low', 7, 0])\ncheck('fixture 2',solve(*('high', 7, 0)),['high', 7, 0])\ncheck('fixture 3',solve(*('low', 7, 1)),['low', 7, 1])\ncheck('fixture 4',solve(*('low', 0, None)),['low', 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-segment-cache-key-includes-rendition","generated_at":"2026-09-29T14:38:45.355901+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: Return the complete local download identity [rendition ID,absolute sequence,optional partial-segment index].","root_cause":"Two quality renditions share a sequence number and collide in the segment cache.","sha256":"e20fbb01a12b11b54d1a25ecd4b3b86468403190ea1ed6b3aebba02a918a7b85","title":"Segment cache key includes rendition · 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":37.825,"exit_code":1,"observations":[{"actual":["low",7],"check":"fixture 1","expected":["low",7,0],"passed":false},{"actual":["high",7],"check":"fixture 2","expected":["high",7,0],"passed":false},{"actual":["low",7],"check":"fixture 3","expected":["low",7,1],"passed":false},{"actual":["low",0],"check":"fixture 4","expected":["low",0,null],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [\"low\", 7], \"expected\": [\"low\", 7, 0], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [\"high\", 7], \"expected\": [\"high\", 7, 0], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [\"low\", 7], \"expected\": [\"low\", 7, 1], \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": [\"low\", 0], \"expected\": [\"low\", 0, null], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":36.969,"exit_code":1,"observations":[{"actual":[7,0],"check":"fixture 1","expected":["low",7,0],"passed":false},{"actual":[7,0],"check":"fixture 2","expected":["high",7,0],"passed":false},{"actual":[7,1],"check":"fixture 3","expected":["low",7,1],"passed":false},{"actual":[0,null],"check":"fixture 4","expected":["low",0,null],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [7, 0], \"expected\": [\"low\", 7, 0], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [7, 0], \"expected\": [\"high\", 7, 0], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [7, 1], \"expected\": [\"low\", 7, 1], \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": [0, null], \"expected\": [\"low\", 0, null], \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":37.594,"exit_code":0,"observations":[{"actual":["low",7,0],"check":"fixture 1","expected":["low",7,0],"passed":true},{"actual":["high",7,0],"check":"fixture 2","expected":["high",7,0],"passed":true},{"actual":["low",7,1],"check":"fixture 3","expected":["low",7,1],"passed":true},{"actual":["low",0,null],"check":"fixture 4","expected":["low",0,null],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [\"low\", 7, 0], \"expected\": [\"low\", 7, 0], \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": [\"high\", 7, 0], \"expected\": [\"high\", 7, 0], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [\"low\", 7, 1], \"expected\": [\"low\", 7, 1], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [\"low\", 0, null], \"expected\": [\"low\", 0, null], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}