{"abstract":"Shifted higher-order channels leak into lower byte values.","category":"Color encoding","checks":4,"contract":"Unpack a 32-bit unsigned big-endian RGBA integer into four bytes, masking each shifted field.","contract_signature":"word","evaluation_group":"xg-unpack-rgba-byte-mask","failed_approach":"Masking with reversed shifts yields ABGR instead of RGBA.","family":"xg-unpack-rgba-byte-mask","id":"FA-10601","implementations":{"attempt":{"sha256":"39e856bf5ae26023d14a57aacd32d827ba4200e78ef625391fcf81e28d3cda00","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(word):\n    return [(word>>shift)&255 for shift in (0,8,16,24)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*(16909060,)), [1, 2, 3, 4])\ncheck('fixture 2', solve(*(255,)), [0, 0, 0, 255])\ncheck('fixture 3', solve(*(4278190080,)), [255, 0, 0, 0])\ncheck('fixture 4', solve(*(0,)), [0, 0, 0, 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":"9068dd00ecbc5115004c35edd2f31fe704746ac8ddbb7535ada3d25f07dc42c8","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(word):\n    return [word>>shift for shift in (24,16,8,0)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*(16909060,)), [1, 2, 3, 4])\ncheck('fixture 2', solve(*(255,)), [0, 0, 0, 255])\ncheck('fixture 3', solve(*(4278190080,)), [255, 0, 0, 0])\ncheck('fixture 4', solve(*(0,)), [0, 0, 0, 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":"xg-unpack-rgba-byte-mask","generated_at":"2026-09-29T14:38:40.540260+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":"Shifted higher-order channels leak into lower byte values.","sha256":"8ed4c0071973f44be675215688fd5dbdde52b52968f63dd7da8ad44278d581a4","title":"Unpack rgba byte mask · 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":41.336,"exit_code":1,"observations":[{"actual":[4,3,2,1],"check":"fixture 1","expected":[1,2,3,4],"passed":false},{"actual":[255,0,0,0],"check":"fixture 2","expected":[0,0,0,255],"passed":false},{"actual":[0,0,0,255],"check":"fixture 3","expected":[255,0,0,0],"passed":false},{"actual":[0,0,0,0],"check":"fixture 4","expected":[0,0,0,0],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [4, 3, 2, 1], \"expected\": [1, 2, 3, 4], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [255, 0, 0, 0], \"expected\": [0, 0, 0, 255], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [0, 0, 0, 255], \"expected\": [255, 0, 0, 0], \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": [0, 0, 0, 0], \"expected\": [0, 0, 0, 0], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.565,"exit_code":1,"observations":[{"actual":[1,258,66051,16909060],"check":"fixture 1","expected":[1,2,3,4],"passed":false},{"actual":[0,0,0,255],"check":"fixture 2","expected":[0,0,0,255],"passed":true},{"actual":[255,65280,16711680,4278190080],"check":"fixture 3","expected":[255,0,0,0],"passed":false},{"actual":[0,0,0,0],"check":"fixture 4","expected":[0,0,0,0],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [1, 258, 66051, 16909060], \"expected\": [1, 2, 3, 4], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [0, 0, 0, 255], \"expected\": [0, 0, 0, 255], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [255, 65280, 16711680, 4278190080], \"expected\": [255, 0, 0, 0], \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": [0, 0, 0, 0], \"expected\": [0, 0, 0, 0], \"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."}}