FA-10596 / Color encoding / Open access
Pack rgba big endian word · case 01
Packing assumes little-endian channel significance instead of the stated integer layout.
ROOT CAUSE
Packing assumes little-endian channel significance instead of the stated integer layout.
VERIFIED REPAIR
Use the stage contract: Pack four integer bytes RGBA into an unsigned word with red as most significant byte and alpha as least significant byte.
Unsuccessful approach: Correcting RGB byte order still discards alpha.
Case contract
Pack four integer bytes RGBA into an unsigned word with red as most significant byte and alpha as least significant byte.
Why this case matters
A deterministic software graphics stage with explicit channel and coordinate conventions; no hardware, device profile or API behavior is inferred.
1 / The failure
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(rgba):
return (rgba[3]<<24)|(rgba[2]<<16)|(rgba[1]<<8)|rgba[0]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve(*([1, 2, 3, 4],)), 16909060)
check('fixture 2', solve(*([0, 0, 0, 255],)), 255)
check('fixture 3', solve(*([255, 0, 0, 0],)), 4278190080)
check('fixture 4', solve(*([0, 0, 0, 0],)), 0)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
| Boundary fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1 | 67305985 | 16909060 | Failed |
| fixture 2 | 4278190080 | 255 | Failed |
| fixture 3 | 255 | 4278190080 | Failed |
| fixture 4 | 0 | 0 | Passed |
SHA-256 / 3d71728d3211febd8faeef4c55c548472f14698867d499758f2b9a7ca475fe37
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(rgba):
return (rgba[0]<<24)|(rgba[1]<<16)|(rgba[2]<<8)
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve(*([1, 2, 3, 4],)), 16909060)
check('fixture 2', solve(*([0, 0, 0, 255],)), 255)
check('fixture 3', solve(*([255, 0, 0, 0],)), 4278190080)
check('fixture 4', solve(*([0, 0, 0, 0],)), 0)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
| Boundary fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1 | 16909056 | 16909060 | Failed |
| fixture 2 | 0 | 255 | Failed |
| fixture 3 | 4278190080 | 4278190080 | Passed |
| fixture 4 | 0 | 0 | Passed |
SHA-256 / 4a762fba071c64533cd7d857c91f1bac926597e8d3e559e13886b6fca41713ed
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(rgba):
return (rgba[0]<<24)|(rgba[1]<<16)|(rgba[2]<<8)|rgba[3]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve(*([1, 2, 3, 4],)), 16909060)
check('fixture 2', solve(*([0, 0, 0, 255],)), 255)
check('fixture 3', solve(*([255, 0, 0, 0],)), 4278190080)
check('fixture 4', solve(*([0, 0, 0, 0],)), 0)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
| Boundary fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1 | 16909060 | 16909060 | Passed |
| fixture 2 | 255 | 255 | Passed |
| fixture 3 | 4278190080 | 4278190080 | Passed |
| fixture 4 | 0 | 0 | Passed |
SHA-256 / 838cb374cf9d1b18e032016790eb910dfa143f8284911a6d9fae7fbaa1727c8b
Verification & scope
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.
Observations recorded using Python 3.12.14 at 2026-09-29T14:38:40.506231+00:00.
Case digest / 4b9393ee1ddab13b697056d9d54866bf9f5ff2ea6b1310bfa4747c70818ce07e