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FA-51371 / Raster clipping / Open access

Opaque occlusion clip: empty records · case 01

Fully clipped or occluded draws lose their explicit empty visibility records.

Verified by executionVariant 1 · 11 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Fully clipped or occluded draws lose their explicit empty visibility records.

THE FAILURE

Fully clipped or occluded draws lose their explicit empty visibility records.

Unsuccessful approach: Keeping empty opaque records still drops fully clipped transparent draws.

Case contract

Draws are supplied back to front as ID, coverage set, opaque flag, clip set and sample-write-enable set. Visibility traverses front to back, subtracting only front opaque written samples. Transparent draws remain visible but do not occlude. Return every draw in original order, including empty visibility, labeled by ID. Repeated IDs are distinct draws. All coverage is finite-target bounded.

Why this case matters

Raster clip state can leak coverage across draws even when every individual region is valid.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(commands, size):
    full=set(range(size))
    out=[]
    for draws in commands:
        occluded=set()
        visible=[]
        for key,coverage,opaque,clip,writes in reversed(draws):
            effective=set(coverage)&set(clip)&set(writes)&full
            remaining=effective-occluded
            if remaining: visible.append([key,sorted(remaining)])
            if opaque: occluded |= effective
        out.append(list(reversed(visible)))
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
if N == 1:
    check('explicit sequence 0', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [1], True, [1], [1]]]], 4), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 1', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], False, [0, 1], [0, 1]]]], 4), [[['back', [0, 1]], ['front', [0, 1]]]])
    check('explicit sequence 2', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0], [0, 1]]]], 4), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 3', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0, 1], [0]]]], 4), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 4', solve([[['back', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 4), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 5', solve([[['back', [0, 1, 2], True, [0, 1, 2], [0, 1, 2]], ['middle', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 4), [[['back', [2]], ['middle', [0]], ['front', [1]]]])
    check('explicit sequence 6', solve([[['z', [0], False, [0], [0]], ['a', [1], False, [1], [1]]]], 4), [[['z', [0]], ['a', [1]]]])
    check('explicit sequence 7', solve([[['a', [0], False, [], [0]], ['b', [1], True, [1], [1]]]], 4), [[['a', []], ['b', [1]]]])
    check('explicit sequence 8', solve([[['same', [0], False, [0], [0]], ['same', [1], False, [1], [1]]]], 4), [[['same', [0]], ['same', [1]]]])
    check('explicit sequence 9', solve([[['a', [0], True, [0], []]]], 4), [[['a', []]]])
    check('explicit sequence 10', solve([[['a', [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], True, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]]]], 4), [[['a', [0, 1, 2, 3]]]])
if N == 2:
    check('explicit sequence 0', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [1], True, [1], [1]]]], 5), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 1', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], False, [0, 1], [0, 1]]]], 5), [[['back', [0, 1]], ['front', [0, 1]]]])
    check('explicit sequence 2', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0], [0, 1]]]], 5), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 3', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0, 1], [0]]]], 5), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 4', solve([[['back', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 5), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 5', solve([[['back', [0, 1, 2], True, [0, 1, 2], [0, 1, 2]], ['middle', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 5), [[['back', [2]], ['middle', [0]], ['front', [1]]]])
    check('explicit sequence 6', solve([[['z', [0], False, [0], [0]], ['a', [1], False, [1], [1]]]], 5), [[['z', [0]], ['a', [1]]]])
    check('explicit sequence 7', solve([[['a', [0], False, [], [0]], ['b', [1], True, [1], [1]]]], 5), [[['a', []], ['b', [1]]]])
    check('explicit sequence 8', solve([[['same', [0], False, [0], [0]], ['same', [1], False, [1], [1]]]], 5), [[['same', [0]], ['same', [1]]]])
    check('explicit sequence 9', solve([[['a', [0], True, [0], []]]], 5), [[['a', []]]])
    check('explicit sequence 10', solve([[['a', [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], True, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]]]], 5), [[['a', [0, 1, 2, 3, 4]]]])
if N == 3:
    check('explicit sequence 0', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [1], True, [1], [1]]]], 6), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 1', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], False, [0, 1], [0, 1]]]], 6), [[['back', [0, 1]], ['front', [0, 1]]]])
    check('explicit sequence 2', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0], [0, 1]]]], 6), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 3', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0, 1], [0]]]], 6), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 4', solve([[['back', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 6), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 5', solve([[['back', [0, 1, 2], True, [0, 1, 2], [0, 1, 2]], ['middle', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 6), [[['back', [2]], ['middle', [0]], ['front', [1]]]])
    check('explicit sequence 6', solve([[['z', [0], False, [0], [0]], ['a', [1], False, [1], [1]]]], 6), [[['z', [0]], ['a', [1]]]])
    check('explicit sequence 7', solve([[['a', [0], False, [], [0]], ['b', [1], True, [1], [1]]]], 6), [[['a', []], ['b', [1]]]])
    check('explicit sequence 8', solve([[['same', [0], False, [0], [0]], ['same', [1], False, [1], [1]]]], 6), [[['same', [0]], ['same', [1]]]])
    check('explicit sequence 9', solve([[['a', [0], True, [0], []]]], 6), [[['a', []]]])
    check('explicit sequence 10', solve([[['a', [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], True, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]]]], 6), [[['a', [0, 1, 2, 3, 4, 5]]]])
if N == 4:
    check('explicit sequence 0', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [1], True, [1], [1]]]], 7), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 1', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], False, [0, 1], [0, 1]]]], 7), [[['back', [0, 1]], ['front', [0, 1]]]])
    check('explicit sequence 2', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0], [0, 1]]]], 7), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 3', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0, 1], [0]]]], 7), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 4', solve([[['back', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 7), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 5', solve([[['back', [0, 1, 2], True, [0, 1, 2], [0, 1, 2]], ['middle', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 7), [[['back', [2]], ['middle', [0]], ['front', [1]]]])
    check('explicit sequence 6', solve([[['z', [0], False, [0], [0]], ['a', [1], False, [1], [1]]]], 7), [[['z', [0]], ['a', [1]]]])
    check('explicit sequence 7', solve([[['a', [0], False, [], [0]], ['b', [1], True, [1], [1]]]], 7), [[['a', []], ['b', [1]]]])
    check('explicit sequence 8', solve([[['same', [0], False, [0], [0]], ['same', [1], False, [1], [1]]]], 7), [[['same', [0]], ['same', [1]]]])
    check('explicit sequence 9', solve([[['a', [0], True, [0], []]]], 7), [[['a', []]]])
    check('explicit sequence 10', solve([[['a', [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], True, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]]]], 7), [[['a', [0, 1, 2, 3, 4, 5, 6]]]])
if N == 5:
    check('explicit sequence 0', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [1], True, [1], [1]]]], 8), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 1', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], False, [0, 1], [0, 1]]]], 8), [[['back', [0, 1]], ['front', [0, 1]]]])
    check('explicit sequence 2', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0], [0, 1]]]], 8), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 3', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0, 1], [0]]]], 8), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 4', solve([[['back', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 8), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 5', solve([[['back', [0, 1, 2], True, [0, 1, 2], [0, 1, 2]], ['middle', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 8), [[['back', [2]], ['middle', [0]], ['front', [1]]]])
    check('explicit sequence 6', solve([[['z', [0], False, [0], [0]], ['a', [1], False, [1], [1]]]], 8), [[['z', [0]], ['a', [1]]]])
    check('explicit sequence 7', solve([[['a', [0], False, [], [0]], ['b', [1], True, [1], [1]]]], 8), [[['a', []], ['b', [1]]]])
    check('explicit sequence 8', solve([[['same', [0], False, [0], [0]], ['same', [1], False, [1], [1]]]], 8), [[['same', [0]], ['same', [1]]]])
    check('explicit sequence 9', solve([[['a', [0], True, [0], []]]], 8), [[['a', []]]])
    check('explicit sequence 10', solve([[['a', [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], True, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]]]], 8), [[['a', [0, 1, 2, 3, 4, 5, 6, 7]]]])
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 fixtureActualExpectedOutcome
explicit sequence 0[[['back', [0]], ['front', [1]]]][[['back', [0]], ['front', [1]]]]Passed
explicit sequence 1[[['back', [0, 1]], ['front', [0, 1]]]][[['back', [0, 1]], ['front', [0, 1]]]]Passed
explicit sequence 2[[['back', [1]], ['front', [0]]]][[['back', [1]], ['front', [0]]]]Passed
explicit sequence 3[[['back', [1]], ['front', [0]]]][[['back', [1]], ['front', [0]]]]Passed
explicit sequence 4[[['back', [0]], ['front', [1]]]][[['back', [0]], ['front', [1]]]]Passed
explicit sequence 5[[['back', [2]], ['middle', [0]], ['front', [1]]]][[['back', [2]], ['middle', [0]], ['front', [1]]]]Passed
explicit sequence 6[[['z', [0]], ['a', [1]]]][[['z', [0]], ['a', [1]]]]Passed
explicit sequence 7[[['b', [1]]]][[['a', []], ['b', [1]]]]Failed
explicit sequence 8[[['same', [0]], ['same', [1]]]][[['same', [0]], ['same', [1]]]]Passed
explicit sequence 9[[]][[['a', []]]]Failed
explicit sequence 10[[['a', [0, 1, 2, 3]]]][[['a', [0, 1, 2, 3]]]]Passed

SHA-256 / 780236a11544a00214a38dbbd115711646d8081728aa6beaaf7f92bd1625d5e5

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(commands, size):
    full=set(range(size))
    out=[]
    for draws in commands:
        occluded=set()
        visible=[]
        for key,coverage,opaque,clip,writes in reversed(draws):
            effective=set(coverage)&set(clip)&set(writes)&full
            remaining=effective-occluded
            if remaining or opaque: visible.append([key,sorted(remaining)])
            if opaque: occluded |= effective
        out.append(list(reversed(visible)))
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
if N == 1:
    check('explicit sequence 0', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [1], True, [1], [1]]]], 4), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 1', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], False, [0, 1], [0, 1]]]], 4), [[['back', [0, 1]], ['front', [0, 1]]]])
    check('explicit sequence 2', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0], [0, 1]]]], 4), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 3', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0, 1], [0]]]], 4), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 4', solve([[['back', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 4), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 5', solve([[['back', [0, 1, 2], True, [0, 1, 2], [0, 1, 2]], ['middle', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 4), [[['back', [2]], ['middle', [0]], ['front', [1]]]])
    check('explicit sequence 6', solve([[['z', [0], False, [0], [0]], ['a', [1], False, [1], [1]]]], 4), [[['z', [0]], ['a', [1]]]])
    check('explicit sequence 7', solve([[['a', [0], False, [], [0]], ['b', [1], True, [1], [1]]]], 4), [[['a', []], ['b', [1]]]])
    check('explicit sequence 8', solve([[['same', [0], False, [0], [0]], ['same', [1], False, [1], [1]]]], 4), [[['same', [0]], ['same', [1]]]])
    check('explicit sequence 9', solve([[['a', [0], True, [0], []]]], 4), [[['a', []]]])
    check('explicit sequence 10', solve([[['a', [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], True, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]]]], 4), [[['a', [0, 1, 2, 3]]]])
if N == 2:
    check('explicit sequence 0', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [1], True, [1], [1]]]], 5), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 1', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], False, [0, 1], [0, 1]]]], 5), [[['back', [0, 1]], ['front', [0, 1]]]])
    check('explicit sequence 2', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0], [0, 1]]]], 5), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 3', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0, 1], [0]]]], 5), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 4', solve([[['back', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 5), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 5', solve([[['back', [0, 1, 2], True, [0, 1, 2], [0, 1, 2]], ['middle', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 5), [[['back', [2]], ['middle', [0]], ['front', [1]]]])
    check('explicit sequence 6', solve([[['z', [0], False, [0], [0]], ['a', [1], False, [1], [1]]]], 5), [[['z', [0]], ['a', [1]]]])
    check('explicit sequence 7', solve([[['a', [0], False, [], [0]], ['b', [1], True, [1], [1]]]], 5), [[['a', []], ['b', [1]]]])
    check('explicit sequence 8', solve([[['same', [0], False, [0], [0]], ['same', [1], False, [1], [1]]]], 5), [[['same', [0]], ['same', [1]]]])
    check('explicit sequence 9', solve([[['a', [0], True, [0], []]]], 5), [[['a', []]]])
    check('explicit sequence 10', solve([[['a', [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], True, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]]]], 5), [[['a', [0, 1, 2, 3, 4]]]])
if N == 3:
    check('explicit sequence 0', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [1], True, [1], [1]]]], 6), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 1', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], False, [0, 1], [0, 1]]]], 6), [[['back', [0, 1]], ['front', [0, 1]]]])
    check('explicit sequence 2', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0], [0, 1]]]], 6), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 3', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0, 1], [0]]]], 6), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 4', solve([[['back', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 6), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 5', solve([[['back', [0, 1, 2], True, [0, 1, 2], [0, 1, 2]], ['middle', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 6), [[['back', [2]], ['middle', [0]], ['front', [1]]]])
    check('explicit sequence 6', solve([[['z', [0], False, [0], [0]], ['a', [1], False, [1], [1]]]], 6), [[['z', [0]], ['a', [1]]]])
    check('explicit sequence 7', solve([[['a', [0], False, [], [0]], ['b', [1], True, [1], [1]]]], 6), [[['a', []], ['b', [1]]]])
    check('explicit sequence 8', solve([[['same', [0], False, [0], [0]], ['same', [1], False, [1], [1]]]], 6), [[['same', [0]], ['same', [1]]]])
    check('explicit sequence 9', solve([[['a', [0], True, [0], []]]], 6), [[['a', []]]])
    check('explicit sequence 10', solve([[['a', [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], True, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]]]], 6), [[['a', [0, 1, 2, 3, 4, 5]]]])
if N == 4:
    check('explicit sequence 0', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [1], True, [1], [1]]]], 7), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 1', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], False, [0, 1], [0, 1]]]], 7), [[['back', [0, 1]], ['front', [0, 1]]]])
    check('explicit sequence 2', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0], [0, 1]]]], 7), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 3', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0, 1], [0]]]], 7), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 4', solve([[['back', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 7), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 5', solve([[['back', [0, 1, 2], True, [0, 1, 2], [0, 1, 2]], ['middle', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 7), [[['back', [2]], ['middle', [0]], ['front', [1]]]])
    check('explicit sequence 6', solve([[['z', [0], False, [0], [0]], ['a', [1], False, [1], [1]]]], 7), [[['z', [0]], ['a', [1]]]])
    check('explicit sequence 7', solve([[['a', [0], False, [], [0]], ['b', [1], True, [1], [1]]]], 7), [[['a', []], ['b', [1]]]])
    check('explicit sequence 8', solve([[['same', [0], False, [0], [0]], ['same', [1], False, [1], [1]]]], 7), [[['same', [0]], ['same', [1]]]])
    check('explicit sequence 9', solve([[['a', [0], True, [0], []]]], 7), [[['a', []]]])
    check('explicit sequence 10', solve([[['a', [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], True, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]]]], 7), [[['a', [0, 1, 2, 3, 4, 5, 6]]]])
if N == 5:
    check('explicit sequence 0', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [1], True, [1], [1]]]], 8), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 1', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], False, [0, 1], [0, 1]]]], 8), [[['back', [0, 1]], ['front', [0, 1]]]])
    check('explicit sequence 2', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0], [0, 1]]]], 8), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 3', solve([[['back', [0, 1], True, [0, 1], [0, 1]], ['front', [0, 1], True, [0, 1], [0]]]], 8), [[['back', [1]], ['front', [0]]]])
    check('explicit sequence 4', solve([[['back', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 8), [[['back', [0]], ['front', [1]]]])
    check('explicit sequence 5', solve([[['back', [0, 1, 2], True, [0, 1, 2], [0, 1, 2]], ['middle', [0], True, [0], [0]], ['front', [1], True, [1], [1]]]], 8), [[['back', [2]], ['middle', [0]], ['front', [1]]]])
    check('explicit sequence 6', solve([[['z', [0], False, [0], [0]], ['a', [1], False, [1], [1]]]], 8), [[['z', [0]], ['a', [1]]]])
    check('explicit sequence 7', solve([[['a', [0], False, [], [0]], ['b', [1], True, [1], [1]]]], 8), [[['a', []], ['b', [1]]]])
    check('explicit sequence 8', solve([[['same', [0], False, [0], [0]], ['same', [1], False, [1], [1]]]], 8), [[['same', [0]], ['same', [1]]]])
    check('explicit sequence 9', solve([[['a', [0], True, [0], []]]], 8), [[['a', []]]])
    check('explicit sequence 10', solve([[['a', [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], True, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]]]], 8), [[['a', [0, 1, 2, 3, 4, 5, 6, 7]]]])
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 fixtureActualExpectedOutcome
explicit sequence 0[[['back', [0]], ['front', [1]]]][[['back', [0]], ['front', [1]]]]Passed
explicit sequence 1[[['back', [0, 1]], ['front', [0, 1]]]][[['back', [0, 1]], ['front', [0, 1]]]]Passed
explicit sequence 2[[['back', [1]], ['front', [0]]]][[['back', [1]], ['front', [0]]]]Passed
explicit sequence 3[[['back', [1]], ['front', [0]]]][[['back', [1]], ['front', [0]]]]Passed
explicit sequence 4[[['back', [0]], ['front', [1]]]][[['back', [0]], ['front', [1]]]]Passed
explicit sequence 5[[['back', [2]], ['middle', [0]], ['front', [1]]]][[['back', [2]], ['middle', [0]], ['front', [1]]]]Passed
explicit sequence 6[[['z', [0]], ['a', [1]]]][[['z', [0]], ['a', [1]]]]Passed
explicit sequence 7[[['b', [1]]]][[['a', []], ['b', [1]]]]Failed
explicit sequence 8[[['same', [0]], ['same', [1]]]][[['same', [0]], ['same', [1]]]]Passed
explicit sequence 9[[['a', []]]][[['a', []]]]Passed
explicit sequence 10[[['a', [0, 1, 2, 3]]]][[['a', [0, 1, 2, 3]]]]Passed

SHA-256 / c18f6a61abd99cd6b2c31c4fd0eef0a9b1b2f4148827e437f0bf974a8889c9a6

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 11 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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Verification & scope

Finite one-dimensional integer sample sets model coverage state only; no geometric intersection, memory layout, GPU or graphics-standard conformance is claimed. 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 2026-09-29T14:45:18.326999+00:00.

Case digest / 78f95cc5139c40afe50ac4935c25bcdeeefb238b0ac86709e3d1d54713e8a45d