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FA-50496 / Raster clipping / Open access

Clip mask cache: cache key global · case 01

Cache population reads the first defined mask instead of the active mask.

Verified by executionVariant 1 · 9 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Cache population reads the first defined mask instead of the active mask.

THE FAILURE

Cache population reads the first defined mask instead of the active mask.

Unsuccessful approach: Keying cache lookup correctly but treating undefined masks as full loses fail-closed behavior.

Case contract

Cache entries store copied coverage and source revisions. Draw recomputes after mask edits. Disable returns full coverage without overwriting cached mask. Rebinding to another name cannot reuse the old name; clearing definitions removes stale entries. Missing definitions clip empty.

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))
    defs={}
    revs={}
    cache={}
    active=None
    enabled=True
    out=[]
    for cmd in commands:
        op=cmd[0]
        if op=='set':
            defs[cmd[1]]=set(cmd[2]) & full
            revs[cmd[1]]=revs.get(cmd[1],0)+1
        elif op=='bind': active=cmd[1]
        elif op=='drop':
            defs.pop(cmd[1],None)
            cache.pop(cmd[1],None)
        elif op=='invalidate': cache.pop(cmd[1],None)
        elif op=='clear': defs.clear(); cache.clear()
        elif op=='disable': enabled=False
        elif op=='enable': enabled=True
        elif op=='draw':
            revision=revs.get(active,0)
            if active not in cache or cache[active][0]!=revision:
                cache[active]=(revision,set(next(iter(defs.values()),set())))
            out.append(sorted(cache[active][1] if enabled else full))
    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([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['set', 'a', [1]], ['draw']], 4), [[0], [1]])
    check('explicit sequence 1', solve([['set', 'a', [0]], ['set', 'b', [2]], ['bind', 'b'], ['draw']], 4), [[2]])
    check('explicit sequence 2', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 4), [[0], []])
    check('explicit sequence 3', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['clear'], ['draw']], 4), [[0], []])
    check('explicit sequence 4', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['disable'], ['draw'], ['enable'], ['draw']], 4), [[0], [0, 1, 2, 3], [0]])
    check('explicit sequence 5', solve([['bind', 'missing'], ['draw']], 4), [[]])
    check('explicit sequence 6', solve([['set', 'a', [0, 99]], ['bind', 'a'], ['draw'], ['invalidate', 'a'], ['draw']], 4), [[0], [0]])
    check('explicit sequence 7', solve([['set', 'a', []], ['bind', 'a'], ['draw']], 4), [[]])
    check('explicit sequence 8', solve([['set', 'a', [0]], ['set', 'b', [1]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 4), [[0], []])
if N == 2:
    check('explicit sequence 0', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['set', 'a', [1]], ['draw']], 5), [[0], [1]])
    check('explicit sequence 1', solve([['set', 'a', [0]], ['set', 'b', [2]], ['bind', 'b'], ['draw']], 5), [[2]])
    check('explicit sequence 2', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 5), [[0], []])
    check('explicit sequence 3', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['clear'], ['draw']], 5), [[0], []])
    check('explicit sequence 4', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['disable'], ['draw'], ['enable'], ['draw']], 5), [[0], [0, 1, 2, 3, 4], [0]])
    check('explicit sequence 5', solve([['bind', 'missing'], ['draw']], 5), [[]])
    check('explicit sequence 6', solve([['set', 'a', [0, 99]], ['bind', 'a'], ['draw'], ['invalidate', 'a'], ['draw']], 5), [[0], [0]])
    check('explicit sequence 7', solve([['set', 'a', []], ['bind', 'a'], ['draw']], 5), [[]])
    check('explicit sequence 8', solve([['set', 'a', [0]], ['set', 'b', [1]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 5), [[0], []])
if N == 3:
    check('explicit sequence 0', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['set', 'a', [1]], ['draw']], 6), [[0], [1]])
    check('explicit sequence 1', solve([['set', 'a', [0]], ['set', 'b', [2]], ['bind', 'b'], ['draw']], 6), [[2]])
    check('explicit sequence 2', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 6), [[0], []])
    check('explicit sequence 3', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['clear'], ['draw']], 6), [[0], []])
    check('explicit sequence 4', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['disable'], ['draw'], ['enable'], ['draw']], 6), [[0], [0, 1, 2, 3, 4, 5], [0]])
    check('explicit sequence 5', solve([['bind', 'missing'], ['draw']], 6), [[]])
    check('explicit sequence 6', solve([['set', 'a', [0, 99]], ['bind', 'a'], ['draw'], ['invalidate', 'a'], ['draw']], 6), [[0], [0]])
    check('explicit sequence 7', solve([['set', 'a', []], ['bind', 'a'], ['draw']], 6), [[]])
    check('explicit sequence 8', solve([['set', 'a', [0]], ['set', 'b', [1]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 6), [[0], []])
if N == 4:
    check('explicit sequence 0', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['set', 'a', [1]], ['draw']], 7), [[0], [1]])
    check('explicit sequence 1', solve([['set', 'a', [0]], ['set', 'b', [2]], ['bind', 'b'], ['draw']], 7), [[2]])
    check('explicit sequence 2', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 7), [[0], []])
    check('explicit sequence 3', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['clear'], ['draw']], 7), [[0], []])
    check('explicit sequence 4', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['disable'], ['draw'], ['enable'], ['draw']], 7), [[0], [0, 1, 2, 3, 4, 5, 6], [0]])
    check('explicit sequence 5', solve([['bind', 'missing'], ['draw']], 7), [[]])
    check('explicit sequence 6', solve([['set', 'a', [0, 99]], ['bind', 'a'], ['draw'], ['invalidate', 'a'], ['draw']], 7), [[0], [0]])
    check('explicit sequence 7', solve([['set', 'a', []], ['bind', 'a'], ['draw']], 7), [[]])
    check('explicit sequence 8', solve([['set', 'a', [0]], ['set', 'b', [1]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 7), [[0], []])
if N == 5:
    check('explicit sequence 0', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['set', 'a', [1]], ['draw']], 8), [[0], [1]])
    check('explicit sequence 1', solve([['set', 'a', [0]], ['set', 'b', [2]], ['bind', 'b'], ['draw']], 8), [[2]])
    check('explicit sequence 2', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 8), [[0], []])
    check('explicit sequence 3', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['clear'], ['draw']], 8), [[0], []])
    check('explicit sequence 4', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['disable'], ['draw'], ['enable'], ['draw']], 8), [[0], [0, 1, 2, 3, 4, 5, 6, 7], [0]])
    check('explicit sequence 5', solve([['bind', 'missing'], ['draw']], 8), [[]])
    check('explicit sequence 6', solve([['set', 'a', [0, 99]], ['bind', 'a'], ['draw'], ['invalidate', 'a'], ['draw']], 8), [[0], [0]])
    check('explicit sequence 7', solve([['set', 'a', []], ['bind', 'a'], ['draw']], 8), [[]])
    check('explicit sequence 8', solve([['set', 'a', [0]], ['set', 'b', [1]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 8), [[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 fixtureActualExpectedOutcome
explicit sequence 0[[0], [1]][[0], [1]]Passed
explicit sequence 1[[0]][[2]]Failed
explicit sequence 2[[0], []][[0], []]Passed
explicit sequence 3[[0], []][[0], []]Passed
explicit sequence 4[[0], [0, 1, 2, 3], [0]][[0], [0, 1, 2, 3], [0]]Passed
explicit sequence 5[[]][[]]Passed
explicit sequence 6[[0], [0]][[0], [0]]Passed
explicit sequence 7[[]][[]]Passed
explicit sequence 8[[0], [1]][[0], []]Failed

SHA-256 / bf82703e89d036fc829471710dede6df1ab26ab20a4d8d3760ea3f58398b2555

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))
    defs={}
    revs={}
    cache={}
    active=None
    enabled=True
    out=[]
    for cmd in commands:
        op=cmd[0]
        if op=='set':
            defs[cmd[1]]=set(cmd[2]) & full
            revs[cmd[1]]=revs.get(cmd[1],0)+1
        elif op=='bind': active=cmd[1]
        elif op=='drop':
            defs.pop(cmd[1],None)
            cache.pop(cmd[1],None)
        elif op=='invalidate': cache.pop(cmd[1],None)
        elif op=='clear': defs.clear(); cache.clear()
        elif op=='disable': enabled=False
        elif op=='enable': enabled=True
        elif op=='draw':
            revision=revs.get(active,0)
            if active not in cache or cache[active][0]!=revision:
                cache[active]=(revision,set(defs.get(active,full)))
            out.append(sorted(cache[active][1] if enabled else full))
    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([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['set', 'a', [1]], ['draw']], 4), [[0], [1]])
    check('explicit sequence 1', solve([['set', 'a', [0]], ['set', 'b', [2]], ['bind', 'b'], ['draw']], 4), [[2]])
    check('explicit sequence 2', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 4), [[0], []])
    check('explicit sequence 3', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['clear'], ['draw']], 4), [[0], []])
    check('explicit sequence 4', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['disable'], ['draw'], ['enable'], ['draw']], 4), [[0], [0, 1, 2, 3], [0]])
    check('explicit sequence 5', solve([['bind', 'missing'], ['draw']], 4), [[]])
    check('explicit sequence 6', solve([['set', 'a', [0, 99]], ['bind', 'a'], ['draw'], ['invalidate', 'a'], ['draw']], 4), [[0], [0]])
    check('explicit sequence 7', solve([['set', 'a', []], ['bind', 'a'], ['draw']], 4), [[]])
    check('explicit sequence 8', solve([['set', 'a', [0]], ['set', 'b', [1]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 4), [[0], []])
if N == 2:
    check('explicit sequence 0', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['set', 'a', [1]], ['draw']], 5), [[0], [1]])
    check('explicit sequence 1', solve([['set', 'a', [0]], ['set', 'b', [2]], ['bind', 'b'], ['draw']], 5), [[2]])
    check('explicit sequence 2', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 5), [[0], []])
    check('explicit sequence 3', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['clear'], ['draw']], 5), [[0], []])
    check('explicit sequence 4', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['disable'], ['draw'], ['enable'], ['draw']], 5), [[0], [0, 1, 2, 3, 4], [0]])
    check('explicit sequence 5', solve([['bind', 'missing'], ['draw']], 5), [[]])
    check('explicit sequence 6', solve([['set', 'a', [0, 99]], ['bind', 'a'], ['draw'], ['invalidate', 'a'], ['draw']], 5), [[0], [0]])
    check('explicit sequence 7', solve([['set', 'a', []], ['bind', 'a'], ['draw']], 5), [[]])
    check('explicit sequence 8', solve([['set', 'a', [0]], ['set', 'b', [1]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 5), [[0], []])
if N == 3:
    check('explicit sequence 0', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['set', 'a', [1]], ['draw']], 6), [[0], [1]])
    check('explicit sequence 1', solve([['set', 'a', [0]], ['set', 'b', [2]], ['bind', 'b'], ['draw']], 6), [[2]])
    check('explicit sequence 2', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 6), [[0], []])
    check('explicit sequence 3', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['clear'], ['draw']], 6), [[0], []])
    check('explicit sequence 4', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['disable'], ['draw'], ['enable'], ['draw']], 6), [[0], [0, 1, 2, 3, 4, 5], [0]])
    check('explicit sequence 5', solve([['bind', 'missing'], ['draw']], 6), [[]])
    check('explicit sequence 6', solve([['set', 'a', [0, 99]], ['bind', 'a'], ['draw'], ['invalidate', 'a'], ['draw']], 6), [[0], [0]])
    check('explicit sequence 7', solve([['set', 'a', []], ['bind', 'a'], ['draw']], 6), [[]])
    check('explicit sequence 8', solve([['set', 'a', [0]], ['set', 'b', [1]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 6), [[0], []])
if N == 4:
    check('explicit sequence 0', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['set', 'a', [1]], ['draw']], 7), [[0], [1]])
    check('explicit sequence 1', solve([['set', 'a', [0]], ['set', 'b', [2]], ['bind', 'b'], ['draw']], 7), [[2]])
    check('explicit sequence 2', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 7), [[0], []])
    check('explicit sequence 3', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['clear'], ['draw']], 7), [[0], []])
    check('explicit sequence 4', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['disable'], ['draw'], ['enable'], ['draw']], 7), [[0], [0, 1, 2, 3, 4, 5, 6], [0]])
    check('explicit sequence 5', solve([['bind', 'missing'], ['draw']], 7), [[]])
    check('explicit sequence 6', solve([['set', 'a', [0, 99]], ['bind', 'a'], ['draw'], ['invalidate', 'a'], ['draw']], 7), [[0], [0]])
    check('explicit sequence 7', solve([['set', 'a', []], ['bind', 'a'], ['draw']], 7), [[]])
    check('explicit sequence 8', solve([['set', 'a', [0]], ['set', 'b', [1]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 7), [[0], []])
if N == 5:
    check('explicit sequence 0', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['set', 'a', [1]], ['draw']], 8), [[0], [1]])
    check('explicit sequence 1', solve([['set', 'a', [0]], ['set', 'b', [2]], ['bind', 'b'], ['draw']], 8), [[2]])
    check('explicit sequence 2', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 8), [[0], []])
    check('explicit sequence 3', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['clear'], ['draw']], 8), [[0], []])
    check('explicit sequence 4', solve([['set', 'a', [0]], ['bind', 'a'], ['draw'], ['disable'], ['draw'], ['enable'], ['draw']], 8), [[0], [0, 1, 2, 3, 4, 5, 6, 7], [0]])
    check('explicit sequence 5', solve([['bind', 'missing'], ['draw']], 8), [[]])
    check('explicit sequence 6', solve([['set', 'a', [0, 99]], ['bind', 'a'], ['draw'], ['invalidate', 'a'], ['draw']], 8), [[0], [0]])
    check('explicit sequence 7', solve([['set', 'a', []], ['bind', 'a'], ['draw']], 8), [[]])
    check('explicit sequence 8', solve([['set', 'a', [0]], ['set', 'b', [1]], ['bind', 'a'], ['draw'], ['drop', 'a'], ['draw']], 8), [[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 fixtureActualExpectedOutcome
explicit sequence 0[[0], [1]][[0], [1]]Passed
explicit sequence 1[[2]][[2]]Passed
explicit sequence 2[[0], [0, 1, 2, 3]][[0], []]Failed
explicit sequence 3[[0], [0, 1, 2, 3]][[0], []]Failed
explicit sequence 4[[0], [0, 1, 2, 3], [0]][[0], [0, 1, 2, 3], [0]]Passed
explicit sequence 5[[0, 1, 2, 3]][[]]Failed
explicit sequence 6[[0], [0]][[0], [0]]Passed
explicit sequence 7[[]][[]]Passed
explicit sequence 8[[0], [0, 1, 2, 3]][[0], []]Failed

SHA-256 / d604d74f10a3e7c6ed9bdb5efe20e356c82b3fb896f4db12e3ce29c49316c4f9

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 9 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.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

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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 2026-09-29T14:45:10.018716+00:00.

Case digest / 527feb9758d93516ef11df5054e1cf42fb6f42bc809e3996efd2ec5f5690a99e