{"abstract":"Row addresses ignore required unpack padding.","category":"Raster memory layout","checks":4,"contract":"Round nonnegative row-byte length upward to a multiple of positive integer unpack alignment; aligned and empty rows stay unchanged.","contract_signature":"row_bytes, alignment","evaluation_group":"xg-pixel-unpack-alignment","failed_approach":"Unconditionally advancing to the next alignment block adds padding to already aligned rows.","family":"xg-pixel-unpack-alignment","id":"FA-10751","implementations":{"attempt":{"sha256":"706b2f96363d6441eafdfdff0e68d67786388f6974cf8dc128b61019a3f9a22f","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(row_bytes, alignment):\n    return (row_bytes//alignment+1)*alignment\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*(3, 4)), 4)\ncheck('fixture 2', solve(*(4, 4)), 4)\ncheck('fixture 3', solve(*(0, 4)), 0)\ncheck('fixture 4', solve(*(9, 8)), 16)\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":"62605d7e1ed2171264da05346e1facf1577f58bf5ad62af38a690bda2b133c05","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(row_bytes, alignment):\n    return row_bytes\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*(3, 4)), 4)\ncheck('fixture 2', solve(*(4, 4)), 4)\ncheck('fixture 3', solve(*(0, 4)), 0)\ncheck('fixture 4', solve(*(9, 8)), 16)\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":"xg-pixel-unpack-alignment","generated_at":"2026-09-29T14:38:41.885022+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic software graphics stage with explicit channel and coordinate conventions; no hardware, device profile or API behavior is inferred.","root_cause":"Row addresses ignore required unpack padding.","sha256":"71a416c9f16a7a464413095e1e364b08de306c380249cded536ddfc1d2ebd802","title":"Pixel unpack alignment · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":38.946,"exit_code":1,"observations":[{"actual":4,"check":"fixture 1","expected":4,"passed":true},{"actual":8,"check":"fixture 2","expected":4,"passed":false},{"actual":4,"check":"fixture 3","expected":0,"passed":false},{"actual":16,"check":"fixture 4","expected":16,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": 4, \"expected\": 4, \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": 8, \"expected\": 4, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": 4, \"expected\": 0, \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": 16, \"expected\": 16, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.303,"exit_code":1,"observations":[{"actual":3,"check":"fixture 1","expected":4,"passed":false},{"actual":4,"check":"fixture 2","expected":4,"passed":true},{"actual":0,"check":"fixture 3","expected":0,"passed":true},{"actual":9,"check":"fixture 4","expected":16,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": 3, \"expected\": 4, \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": 4, \"expected\": 4, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 9, \"expected\": 16, \"passed\": false}], \"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."}}