FAILURE MAP
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FA-45166 / Data systems / Open access

Dictionary equality reports false when either lane is null · case 01

Dictionary equality reports false when either lane is null.

Verified by executionVariant 1 · 7 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

dictionary-comparison: Dictionary equality reports false when either lane is null.

VERIFIED REPAIR

Preserve the stated physical representation and operation order: Compare two dictionary vectors row by row using decoded values, not local codes. Null validity yields UNKNOWN(None), including two null lanes. Dictionary entries themselves are ordinary integer values. Output follows the supplied pair selection order.

Unsuccessful approach: Reporting equality for two nulls violates ordinary three-valued comparison.

Case contract

Compare two dictionary vectors row by row using decoded values, not local codes. Null validity yields UNKNOWN(None), including two null lanes. Dictionary entries themselves are ordinary integer values. Output follows the supplied pair selection order.

Why this case matters

A bounded deterministic data engine model makes representation and changelog faults reproducible.

1 / The failure

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

N = 1
observations = []
def solve(d):
    try:
        ad,ac,av,bd,bc,bv,pairs=d
        out=[]
        for ai,bi in pairs:
            if not av[ai] or not bv[bi]: out.append(False); continue
            a=ad[ac[ai]]
            b=bd[bc[bi]]
            out.append(a==b)
        return out
    except (IndexError, KeyError, ValueError, StopIteration) as exc:
        return {"representation_error": type(exc).__name__}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
if N == 1:
    check('different codebooks', solve([[1, 2], [0, 1], [True, True], [2, 1], [0, 1], [True, True], [[0, 1], [0, 0], [1, 0]]]), [True, False, True])
    check('unknown left', solve([[1], [0], [False], [1], [0], [True], [[0, 0]]]), [None])
    check('both unknown', solve([[1], [0], [False], [1], [0], [False], [[0, 0]]]), [None])
    check('pair validity', solve([[1, 2], [0, 1], [True, False], [1, 2], [0, 1], [False, True], [[0, 1], [1, 0]]]), [False, None])
    check('order', solve([[1, 2], [0, 1], [True, True], [1, 2], [0, 1], [True, True], [[1, 0], [0, 0]]]), [False, True])
    check('repeat', solve([[1], [0], [True], [1], [0], [True], [[0, 0], [0, 0]]]), [True, True])
    check('empty pairs', solve([[1], [0], [True], [1], [0], [True], []]), [])
elif N == 2:
    check('different codebooks', solve([[2, 3], [0, 1], [True, True], [3, 2], [0, 1], [True, True], [[0, 1], [0, 0], [1, 0]]]), [True, False, True])
    check('unknown left', solve([[2], [0], [False], [2], [0], [True], [[0, 0]]]), [None])
    check('both unknown', solve([[2], [0], [False], [2], [0], [False], [[0, 0]]]), [None])
    check('pair validity', solve([[2, 3], [0, 1], [True, False], [2, 3], [0, 1], [False, True], [[0, 1], [1, 0]]]), [False, None])
    check('order', solve([[2, 3], [0, 1], [True, True], [2, 3], [0, 1], [True, True], [[1, 0], [0, 0]]]), [False, True])
    check('repeat', solve([[2], [0], [True], [2], [0], [True], [[0, 0], [0, 0]]]), [True, True])
    check('empty pairs', solve([[2], [0], [True], [2], [0], [True], []]), [])
elif N == 3:
    check('different codebooks', solve([[3, 4], [0, 1], [True, True], [4, 3], [0, 1], [True, True], [[0, 1], [0, 0], [1, 0]]]), [True, False, True])
    check('unknown left', solve([[3], [0], [False], [3], [0], [True], [[0, 0]]]), [None])
    check('both unknown', solve([[3], [0], [False], [3], [0], [False], [[0, 0]]]), [None])
    check('pair validity', solve([[3, 4], [0, 1], [True, False], [3, 4], [0, 1], [False, True], [[0, 1], [1, 0]]]), [False, None])
    check('order', solve([[3, 4], [0, 1], [True, True], [3, 4], [0, 1], [True, True], [[1, 0], [0, 0]]]), [False, True])
    check('repeat', solve([[3], [0], [True], [3], [0], [True], [[0, 0], [0, 0]]]), [True, True])
    check('empty pairs', solve([[3], [0], [True], [3], [0], [True], []]), [])
elif N == 4:
    check('different codebooks', solve([[4, 5], [0, 1], [True, True], [5, 4], [0, 1], [True, True], [[0, 1], [0, 0], [1, 0]]]), [True, False, True])
    check('unknown left', solve([[4], [0], [False], [4], [0], [True], [[0, 0]]]), [None])
    check('both unknown', solve([[4], [0], [False], [4], [0], [False], [[0, 0]]]), [None])
    check('pair validity', solve([[4, 5], [0, 1], [True, False], [4, 5], [0, 1], [False, True], [[0, 1], [1, 0]]]), [False, None])
    check('order', solve([[4, 5], [0, 1], [True, True], [4, 5], [0, 1], [True, True], [[1, 0], [0, 0]]]), [False, True])
    check('repeat', solve([[4], [0], [True], [4], [0], [True], [[0, 0], [0, 0]]]), [True, True])
    check('empty pairs', solve([[4], [0], [True], [4], [0], [True], []]), [])
elif N == 5:
    check('different codebooks', solve([[5, 6], [0, 1], [True, True], [6, 5], [0, 1], [True, True], [[0, 1], [0, 0], [1, 0]]]), [True, False, True])
    check('unknown left', solve([[5], [0], [False], [5], [0], [True], [[0, 0]]]), [None])
    check('both unknown', solve([[5], [0], [False], [5], [0], [False], [[0, 0]]]), [None])
    check('pair validity', solve([[5, 6], [0, 1], [True, False], [5, 6], [0, 1], [False, True], [[0, 1], [1, 0]]]), [False, None])
    check('order', solve([[5, 6], [0, 1], [True, True], [5, 6], [0, 1], [True, True], [[1, 0], [0, 0]]]), [False, True])
    check('repeat', solve([[5], [0], [True], [5], [0], [True], [[0, 0], [0, 0]]]), [True, True])
    check('empty pairs', solve([[5], [0], [True], [5], [0], [True], []]), [])
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
different codebooks[True, False, True][True, False, True]Passed
unknown left[False][None]Failed
both unknown[False][None]Failed
pair validity[False, False][False, None]Failed
order[False, True][False, True]Passed
repeat[True, True][True, True]Passed
empty pairs[][]Passed

SHA-256 / 43e9378d316806f756652145e44465fe4d2167be20887065aafde1ede5d07f06

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(d):
    try:
        ad,ac,av,bd,bc,bv,pairs=d
        out=[]
        for ai,bi in pairs:
            if not av[ai] or not bv[bi]: out.append(not av[ai] and not bv[bi]); continue
            a=ad[ac[ai]]
            b=bd[bc[bi]]
            out.append(a==b)
        return out
    except (IndexError, KeyError, ValueError, StopIteration) as exc:
        return {"representation_error": type(exc).__name__}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
if N == 1:
    check('different codebooks', solve([[1, 2], [0, 1], [True, True], [2, 1], [0, 1], [True, True], [[0, 1], [0, 0], [1, 0]]]), [True, False, True])
    check('unknown left', solve([[1], [0], [False], [1], [0], [True], [[0, 0]]]), [None])
    check('both unknown', solve([[1], [0], [False], [1], [0], [False], [[0, 0]]]), [None])
    check('pair validity', solve([[1, 2], [0, 1], [True, False], [1, 2], [0, 1], [False, True], [[0, 1], [1, 0]]]), [False, None])
    check('order', solve([[1, 2], [0, 1], [True, True], [1, 2], [0, 1], [True, True], [[1, 0], [0, 0]]]), [False, True])
    check('repeat', solve([[1], [0], [True], [1], [0], [True], [[0, 0], [0, 0]]]), [True, True])
    check('empty pairs', solve([[1], [0], [True], [1], [0], [True], []]), [])
elif N == 2:
    check('different codebooks', solve([[2, 3], [0, 1], [True, True], [3, 2], [0, 1], [True, True], [[0, 1], [0, 0], [1, 0]]]), [True, False, True])
    check('unknown left', solve([[2], [0], [False], [2], [0], [True], [[0, 0]]]), [None])
    check('both unknown', solve([[2], [0], [False], [2], [0], [False], [[0, 0]]]), [None])
    check('pair validity', solve([[2, 3], [0, 1], [True, False], [2, 3], [0, 1], [False, True], [[0, 1], [1, 0]]]), [False, None])
    check('order', solve([[2, 3], [0, 1], [True, True], [2, 3], [0, 1], [True, True], [[1, 0], [0, 0]]]), [False, True])
    check('repeat', solve([[2], [0], [True], [2], [0], [True], [[0, 0], [0, 0]]]), [True, True])
    check('empty pairs', solve([[2], [0], [True], [2], [0], [True], []]), [])
elif N == 3:
    check('different codebooks', solve([[3, 4], [0, 1], [True, True], [4, 3], [0, 1], [True, True], [[0, 1], [0, 0], [1, 0]]]), [True, False, True])
    check('unknown left', solve([[3], [0], [False], [3], [0], [True], [[0, 0]]]), [None])
    check('both unknown', solve([[3], [0], [False], [3], [0], [False], [[0, 0]]]), [None])
    check('pair validity', solve([[3, 4], [0, 1], [True, False], [3, 4], [0, 1], [False, True], [[0, 1], [1, 0]]]), [False, None])
    check('order', solve([[3, 4], [0, 1], [True, True], [3, 4], [0, 1], [True, True], [[1, 0], [0, 0]]]), [False, True])
    check('repeat', solve([[3], [0], [True], [3], [0], [True], [[0, 0], [0, 0]]]), [True, True])
    check('empty pairs', solve([[3], [0], [True], [3], [0], [True], []]), [])
elif N == 4:
    check('different codebooks', solve([[4, 5], [0, 1], [True, True], [5, 4], [0, 1], [True, True], [[0, 1], [0, 0], [1, 0]]]), [True, False, True])
    check('unknown left', solve([[4], [0], [False], [4], [0], [True], [[0, 0]]]), [None])
    check('both unknown', solve([[4], [0], [False], [4], [0], [False], [[0, 0]]]), [None])
    check('pair validity', solve([[4, 5], [0, 1], [True, False], [4, 5], [0, 1], [False, True], [[0, 1], [1, 0]]]), [False, None])
    check('order', solve([[4, 5], [0, 1], [True, True], [4, 5], [0, 1], [True, True], [[1, 0], [0, 0]]]), [False, True])
    check('repeat', solve([[4], [0], [True], [4], [0], [True], [[0, 0], [0, 0]]]), [True, True])
    check('empty pairs', solve([[4], [0], [True], [4], [0], [True], []]), [])
elif N == 5:
    check('different codebooks', solve([[5, 6], [0, 1], [True, True], [6, 5], [0, 1], [True, True], [[0, 1], [0, 0], [1, 0]]]), [True, False, True])
    check('unknown left', solve([[5], [0], [False], [5], [0], [True], [[0, 0]]]), [None])
    check('both unknown', solve([[5], [0], [False], [5], [0], [False], [[0, 0]]]), [None])
    check('pair validity', solve([[5, 6], [0, 1], [True, False], [5, 6], [0, 1], [False, True], [[0, 1], [1, 0]]]), [False, None])
    check('order', solve([[5, 6], [0, 1], [True, True], [5, 6], [0, 1], [True, True], [[1, 0], [0, 0]]]), [False, True])
    check('repeat', solve([[5], [0], [True], [5], [0], [True], [[0, 0], [0, 0]]]), [True, True])
    check('empty pairs', solve([[5], [0], [True], [5], [0], [True], []]), [])
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
different codebooks[True, False, True][True, False, True]Passed
unknown left[False][None]Failed
both unknown[True][None]Failed
pair validity[False, True][False, None]Failed
order[False, True][False, True]Passed
repeat[True, True][True, True]Passed
empty pairs[][]Passed

SHA-256 / 8b014edf9a077a45916e03a9e4a61d71514a910d375b7e3e138896c43d2d1a4a

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(d):
    try:
        ad,ac,av,bd,bc,bv,pairs=d
        out=[]
        for ai,bi in pairs:
            if not av[ai] or not bv[bi]: out.append(None); continue
            a=ad[ac[ai]]
            b=bd[bc[bi]]
            out.append(a==b)
        return out
    except (IndexError, KeyError, ValueError, StopIteration) as exc:
        return {"representation_error": type(exc).__name__}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
if N == 1:
    check('different codebooks', solve([[1, 2], [0, 1], [True, True], [2, 1], [0, 1], [True, True], [[0, 1], [0, 0], [1, 0]]]), [True, False, True])
    check('unknown left', solve([[1], [0], [False], [1], [0], [True], [[0, 0]]]), [None])
    check('both unknown', solve([[1], [0], [False], [1], [0], [False], [[0, 0]]]), [None])
    check('pair validity', solve([[1, 2], [0, 1], [True, False], [1, 2], [0, 1], [False, True], [[0, 1], [1, 0]]]), [False, None])
    check('order', solve([[1, 2], [0, 1], [True, True], [1, 2], [0, 1], [True, True], [[1, 0], [0, 0]]]), [False, True])
    check('repeat', solve([[1], [0], [True], [1], [0], [True], [[0, 0], [0, 0]]]), [True, True])
    check('empty pairs', solve([[1], [0], [True], [1], [0], [True], []]), [])
elif N == 2:
    check('different codebooks', solve([[2, 3], [0, 1], [True, True], [3, 2], [0, 1], [True, True], [[0, 1], [0, 0], [1, 0]]]), [True, False, True])
    check('unknown left', solve([[2], [0], [False], [2], [0], [True], [[0, 0]]]), [None])
    check('both unknown', solve([[2], [0], [False], [2], [0], [False], [[0, 0]]]), [None])
    check('pair validity', solve([[2, 3], [0, 1], [True, False], [2, 3], [0, 1], [False, True], [[0, 1], [1, 0]]]), [False, None])
    check('order', solve([[2, 3], [0, 1], [True, True], [2, 3], [0, 1], [True, True], [[1, 0], [0, 0]]]), [False, True])
    check('repeat', solve([[2], [0], [True], [2], [0], [True], [[0, 0], [0, 0]]]), [True, True])
    check('empty pairs', solve([[2], [0], [True], [2], [0], [True], []]), [])
elif N == 3:
    check('different codebooks', solve([[3, 4], [0, 1], [True, True], [4, 3], [0, 1], [True, True], [[0, 1], [0, 0], [1, 0]]]), [True, False, True])
    check('unknown left', solve([[3], [0], [False], [3], [0], [True], [[0, 0]]]), [None])
    check('both unknown', solve([[3], [0], [False], [3], [0], [False], [[0, 0]]]), [None])
    check('pair validity', solve([[3, 4], [0, 1], [True, False], [3, 4], [0, 1], [False, True], [[0, 1], [1, 0]]]), [False, None])
    check('order', solve([[3, 4], [0, 1], [True, True], [3, 4], [0, 1], [True, True], [[1, 0], [0, 0]]]), [False, True])
    check('repeat', solve([[3], [0], [True], [3], [0], [True], [[0, 0], [0, 0]]]), [True, True])
    check('empty pairs', solve([[3], [0], [True], [3], [0], [True], []]), [])
elif N == 4:
    check('different codebooks', solve([[4, 5], [0, 1], [True, True], [5, 4], [0, 1], [True, True], [[0, 1], [0, 0], [1, 0]]]), [True, False, True])
    check('unknown left', solve([[4], [0], [False], [4], [0], [True], [[0, 0]]]), [None])
    check('both unknown', solve([[4], [0], [False], [4], [0], [False], [[0, 0]]]), [None])
    check('pair validity', solve([[4, 5], [0, 1], [True, False], [4, 5], [0, 1], [False, True], [[0, 1], [1, 0]]]), [False, None])
    check('order', solve([[4, 5], [0, 1], [True, True], [4, 5], [0, 1], [True, True], [[1, 0], [0, 0]]]), [False, True])
    check('repeat', solve([[4], [0], [True], [4], [0], [True], [[0, 0], [0, 0]]]), [True, True])
    check('empty pairs', solve([[4], [0], [True], [4], [0], [True], []]), [])
elif N == 5:
    check('different codebooks', solve([[5, 6], [0, 1], [True, True], [6, 5], [0, 1], [True, True], [[0, 1], [0, 0], [1, 0]]]), [True, False, True])
    check('unknown left', solve([[5], [0], [False], [5], [0], [True], [[0, 0]]]), [None])
    check('both unknown', solve([[5], [0], [False], [5], [0], [False], [[0, 0]]]), [None])
    check('pair validity', solve([[5, 6], [0, 1], [True, False], [5, 6], [0, 1], [False, True], [[0, 1], [1, 0]]]), [False, None])
    check('order', solve([[5, 6], [0, 1], [True, True], [5, 6], [0, 1], [True, True], [[1, 0], [0, 0]]]), [False, True])
    check('repeat', solve([[5], [0], [True], [5], [0], [True], [[0, 0], [0, 0]]]), [True, True])
    check('empty pairs', solve([[5], [0], [True], [5], [0], [True], []]), [])
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
different codebooks[True, False, True][True, False, True]Passed
unknown left[None][None]Passed
both unknown[None][None]Passed
pair validity[False, None][False, None]Passed
order[False, True][False, True]Passed
repeat[True, True][True, True]Passed
empty pairs[][]Passed

SHA-256 / c94f7c27bc56b4a625d824c4e8b97884fa2acdbe7a9b8cc64015d7d6f3d5c5a6

Verification & scope

Offline stipulated semantics over valid small inputs; no performance, concurrency, or production-engine conformance claim. 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 2026-09-29T14:44:19.412505+00:00.

Case digest / 319e010986a5b7422c95ca51cd198112a9241e01fa490572a1e5ae8832063d52