{"abstract":"A device callback returns fewer samples than the hardware requested.","category":"Audio frame buffers","checks":4,"contract":"Produce exactly nonnegative requested mono signed-PCM samples, filling a shortage with zero and excluding surplus.","evaluation_group":"xaud-underrun-zero-fill","failed_approach":"Padding without trimming supplies excess samples on non-underrun callbacks.","family":"xaud-underrun-zero-fill","id":"FA-10876","implementations":{"attempt":{"sha256":"e26a797e0a0421521a8ded74b7d25d30cbec11982f241663f1d1f8b16dcebff9","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(available, requested):\n    return list(available)+[0]*max(0,requested-len(available))\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([1], 3)),[1, 0, 0])\ncheck('fixture 2',solve(*([1, 2, 3], 2)),[1, 2])\ncheck('fixture 3',solve(*([], 2)),[0, 0])\ncheck('fixture 4',solve(*([1], 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":"78adc35af967f66873183bc1d455f07148b45d4ac76d8d9b54d7c9d388ebb325","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(available, requested):\n    return list(available[:requested])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([1], 3)),[1, 0, 0])\ncheck('fixture 2',solve(*([1, 2, 3], 2)),[1, 2])\ncheck('fixture 3',solve(*([], 2)),[0, 0])\ncheck('fixture 4',solve(*([1], 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":"487bd1356c02756686cceaf7a29c355e973acf09f3d2f5b6b27dc6ecc12aaa1a","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(available, requested):\n    return list(available[:requested])+[0]*max(0,requested-len(available))\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([1], 3)),[1, 0, 0])\ncheck('fixture 2',solve(*([1, 2, 3], 2)),[1, 2])\ncheck('fixture 3',solve(*([], 2)),[0, 0])\ncheck('fixture 4',solve(*([1], 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-underrun-zero-fill","generated_at":"2026-09-29T14:38:43.067097+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: Produce exactly nonnegative requested mono signed-PCM samples, filling a shortage with zero and excluding surplus.","root_cause":"A device callback returns fewer samples than the hardware requested.","sha256":"394e507a0602d277b85c3af82b9d9a7eb7873d656ab15fbf97849023cb1fd99e","title":"Underrun zero fill · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":41.6,"exit_code":1,"observations":[{"actual":[1,0,0],"check":"fixture 1","expected":[1,0,0],"passed":true},{"actual":[1,2,3],"check":"fixture 2","expected":[1,2],"passed":false},{"actual":[0,0],"check":"fixture 3","expected":[0,0],"passed":true},{"actual":[1],"check":"fixture 4","expected":[],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [1, 0, 0], \"expected\": [1, 0, 0], \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": [1, 2, 3], \"expected\": [1, 2], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [0, 0], \"expected\": [0, 0], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [1], \"expected\": [], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.962,"exit_code":1,"observations":[{"actual":[1],"check":"fixture 1","expected":[1,0,0],"passed":false},{"actual":[1,2],"check":"fixture 2","expected":[1,2],"passed":true},{"actual":[],"check":"fixture 3","expected":[0,0],"passed":false},{"actual":[],"check":"fixture 4","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [1], \"expected\": [1, 0, 0], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [1, 2], \"expected\": [1, 2], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [], \"expected\": [0, 0], \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":40.88,"exit_code":0,"observations":[{"actual":[1,0,0],"check":"fixture 1","expected":[1,0,0],"passed":true},{"actual":[1,2],"check":"fixture 2","expected":[1,2],"passed":true},{"actual":[0,0],"check":"fixture 3","expected":[0,0],"passed":true},{"actual":[],"check":"fixture 4","expected":[],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [1, 0, 0], \"expected\": [1, 0, 0], \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": [1, 2], \"expected\": [1, 2], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [0, 0], \"expected\": [0, 0], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}