{"abstract":"Truncating the tail retains stale buffered audio and drops newest input.","category":"Audio frame buffers","checks":4,"contract":"Append mono samples and retain the newest at most nonnegative capacity samples for a drop-oldest real-time buffer.","evaluation_group":"xaud-overrun-drops-oldest-frames","failed_approach":"Replacing the buffer with only incoming audio discards still-useful old samples before capacity is reached.","family":"xaud-overrun-drops-oldest-frames","id":"FA-10881","implementations":{"attempt":{"sha256":"fd71ce966e1bdc64fd34d224bc0efa492e49a650844da08b07bd93dec7212267","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(buffer, incoming, capacity):\n    return list(incoming[-capacity:]) if capacity else []\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([1, 2], [3, 4], 3)),[2, 3, 4])\ncheck('fixture 2',solve(*([1], [2], 3)),[1, 2])\ncheck('fixture 3',solve(*([], [1, 2], 1)),[2])\ncheck('fixture 4',solve(*([1], [2], 0)),[])\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":"cc171a3a2a3c4c72c734d0d8ef734d8d0f4c6b0e5f703ab2eb26313d70e200d0","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(buffer, incoming, capacity):\n    return (list(buffer)+list(incoming))[:capacity]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([1, 2], [3, 4], 3)),[2, 3, 4])\ncheck('fixture 2',solve(*([1], [2], 3)),[1, 2])\ncheck('fixture 3',solve(*([], [1, 2], 1)),[2])\ncheck('fixture 4',solve(*([1], [2], 0)),[])\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":"d961728abc99b77e5a70e112d3bee639cd6f127f33e0d6941ec24433aa6e82bb","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(buffer, incoming, capacity):\n    return (list(buffer)+list(incoming))[-capacity:] if capacity else []\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([1, 2], [3, 4], 3)),[2, 3, 4])\ncheck('fixture 2',solve(*([1], [2], 3)),[1, 2])\ncheck('fixture 3',solve(*([], [1, 2], 1)),[2])\ncheck('fixture 4',solve(*([1], [2], 0)),[])\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":"xaud-overrun-drops-oldest-frames","generated_at":"2026-09-29T14:38:43.109261+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A pure Python local audio pipeline stage with explicit sample formats and frame conventions; no real-time device or signal-spectrum claims.","repair":"Apply the explicit PCM/playback contract: Append mono samples and retain the newest at most nonnegative capacity samples for a drop-oldest real-time buffer.","root_cause":"Truncating the tail retains stale buffered audio and drops newest input.","sha256":"0c131fecd7be182019ad9b0e92610fca26343ef0851c36470110f757755ebe78","title":"Overrun drops oldest frames · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":40.344,"exit_code":1,"observations":[{"actual":[3,4],"check":"fixture 1","expected":[2,3,4],"passed":false},{"actual":[2],"check":"fixture 2","expected":[1,2],"passed":false},{"actual":[2],"check":"fixture 3","expected":[2],"passed":true},{"actual":[],"check":"fixture 4","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [3, 4], \"expected\": [2, 3, 4], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [2], \"expected\": [1, 2], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [2], \"expected\": [2], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.062,"exit_code":1,"observations":[{"actual":[1,2,3],"check":"fixture 1","expected":[2,3,4],"passed":false},{"actual":[1,2],"check":"fixture 2","expected":[1,2],"passed":true},{"actual":[1],"check":"fixture 3","expected":[2],"passed":false},{"actual":[],"check":"fixture 4","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [1, 2, 3], \"expected\": [2, 3, 4], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [1, 2], \"expected\": [1, 2], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [1], \"expected\": [2], \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":40.142,"exit_code":0,"observations":[{"actual":[2,3,4],"check":"fixture 1","expected":[2,3,4],"passed":true},{"actual":[1,2],"check":"fixture 2","expected":[1,2],"passed":true},{"actual":[2],"check":"fixture 3","expected":[2],"passed":true},{"actual":[],"check":"fixture 4","expected":[],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [2, 3, 4], \"expected\": [2, 3, 4], \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": [1, 2], \"expected\": [1, 2], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [2], \"expected\": [2], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}