FA-10746 / Raster memory layout / Open access
Subimage row offset · case 01
The horizontal subimage origin is ignored.
ROOT CAUSE
The horizontal subimage origin is ignored.
VERIFIED REPAIR
Use the stage contract: Extract an in-bounds nonnegative integer rectangular subimage from rectangular row storage, retaining selected row and column offsets.
Unsuccessful approach: Correcting columns while dropping the vertical origin reads the wrong scanlines.
Case contract
Extract an in-bounds nonnegative integer rectangular subimage from rectangular row storage, retaining selected row and column offsets.
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(rows, x, y, width, height):
return [list(row[:width]) for row in rows[y:y+height]]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve(*([[1, 2, 3], [4, 5, 6], [7, 8, 9]], 1, 1, 2, 2)), [[5, 6], [8, 9]])
check('fixture 2', solve(*([[1, 2], [3, 4]], 0, 0, 1, 1)), [[1]])
check('fixture 3', solve(*([[1, 2]], 1, 0, 1, 1)), [[2]])
check('fixture 4', solve(*([[1]], 0, 0, 0, 1)), [[]])
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 | [[4, 5], [7, 8]] | [[5, 6], [8, 9]] | Failed |
| fixture 2 | [[1]] | [[1]] | Passed |
| fixture 3 | [[1]] | [[2]] | Failed |
| fixture 4 | [[]] | [[]] | Passed |
SHA-256 / 1faa8efc320175d9748f26108ee649a5e29e894a514ca99610cc0d14007a17e1
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(rows, x, y, width, height):
return [list(row[x:x+width]) for row in rows[:height]]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve(*([[1, 2, 3], [4, 5, 6], [7, 8, 9]], 1, 1, 2, 2)), [[5, 6], [8, 9]])
check('fixture 2', solve(*([[1, 2], [3, 4]], 0, 0, 1, 1)), [[1]])
check('fixture 3', solve(*([[1, 2]], 1, 0, 1, 1)), [[2]])
check('fixture 4', solve(*([[1]], 0, 0, 0, 1)), [[]])
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 | [[2, 3], [5, 6]] | [[5, 6], [8, 9]] | Failed |
| fixture 2 | [[1]] | [[1]] | Passed |
| fixture 3 | [[2]] | [[2]] | Passed |
| fixture 4 | [[]] | [[]] | Passed |
SHA-256 / 147ede46717469fc1cf41f13f2d48e98ad1bdba78df11650771d3852c90de123
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(rows, x, y, width, height):
return [list(row[x:x+width]) for row in rows[y:y+height]]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve(*([[1, 2, 3], [4, 5, 6], [7, 8, 9]], 1, 1, 2, 2)), [[5, 6], [8, 9]])
check('fixture 2', solve(*([[1, 2], [3, 4]], 0, 0, 1, 1)), [[1]])
check('fixture 3', solve(*([[1, 2]], 1, 0, 1, 1)), [[2]])
check('fixture 4', solve(*([[1]], 0, 0, 0, 1)), [[]])
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 | [[5, 6], [8, 9]] | [[5, 6], [8, 9]] | Passed |
| fixture 2 | [[1]] | [[1]] | Passed |
| fixture 3 | [[2]] | [[2]] | Passed |
| fixture 4 | [[]] | [[]] | Passed |
SHA-256 / c43a6d9b684b7d47d4a56144ae0e9a24203e9c3ac35c9c361a4fb6a2dde4c788
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 2026-09-29T14:38:41.839179+00:00.
Case digest / 421fcbbc3ff636db4d7c6f9232544192ebf1f7e30bb2eabf29e23a1931e37f2b