FAILURE MAP
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FA-44391 / Data systems / Open access

Null dictionary lanes are decoded as real values · case 01

Null dictionary lanes are decoded as real values.

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

ROOT CAUSE

dictionary-unification: Null dictionary lanes are decoded as real values.

THE FAILURE

dictionary-unification: Null dictionary lanes are decoded as real values.

Unsuccessful approach: A zero code is a valid global value, not a null marker.

Case contract

Unify dictionaries from ordered batches by first encountered dictionary value, including unused values. Rewrite valid local indices into the unified domain, retaining null lanes and batch boundaries; duplicate dictionary values share one code.

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:
        merged=[]; batches=[]
        for dictionary,codes,valid in d:
            for value in dictionary:
                if value not in merged: merged.append(value)
            mapping=[merged.index(v) if v in merged else -1 for v in dictionary]
            rewritten=[mapping[c] for i,c in enumerate(codes)]
            batches.append(rewritten)
        return [merged,batches]
    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('overlapping domains', solve([[[1, 2], [1, 0], [True, True]], [[3, 1], [1, 0], [True, True]]]), [[1, 2, 3], [[1, 0], [0, 2]]])
    check('unused values', solve([[[1, 2, 3], [1], [True]]]), [[1, 2, 3], [[1]]])
    check('nonadjacent duplicate', solve([[[1, 2, 1], [2, 0], [True, True]]]), [[1, 2], [[0, 0]]])
    check('null lanes', solve([[[1, 2], [1, 0], [False, True]]]), [[1, 2], [[None, 0]]])
    check('empty batch', solve([[[1], [], []], [[2], [0], [True]]]), [[1, 2], [[], [1]]])
    check('no batches', solve([]), [[], []])
    check('single domain', solve([[[1], [0, 0], [True, True]]]), [[1], [[0, 0]]])
elif N == 2:
    check('overlapping domains', solve([[[2, 3], [1, 0], [True, True]], [[4, 2], [1, 0], [True, True]]]), [[2, 3, 4], [[1, 0], [0, 2]]])
    check('unused values', solve([[[2, 3, 4], [1], [True]]]), [[2, 3, 4], [[1]]])
    check('nonadjacent duplicate', solve([[[2, 3, 2], [2, 0], [True, True]]]), [[2, 3], [[0, 0]]])
    check('null lanes', solve([[[2, 3], [1, 0], [False, True]]]), [[2, 3], [[None, 0]]])
    check('empty batch', solve([[[2], [], []], [[3], [0], [True]]]), [[2, 3], [[], [1]]])
    check('no batches', solve([]), [[], []])
    check('single domain', solve([[[2], [0, 0], [True, True]]]), [[2], [[0, 0]]])
elif N == 3:
    check('overlapping domains', solve([[[3, 4], [1, 0], [True, True]], [[5, 3], [1, 0], [True, True]]]), [[3, 4, 5], [[1, 0], [0, 2]]])
    check('unused values', solve([[[3, 4, 5], [1], [True]]]), [[3, 4, 5], [[1]]])
    check('nonadjacent duplicate', solve([[[3, 4, 3], [2, 0], [True, True]]]), [[3, 4], [[0, 0]]])
    check('null lanes', solve([[[3, 4], [1, 0], [False, True]]]), [[3, 4], [[None, 0]]])
    check('empty batch', solve([[[3], [], []], [[4], [0], [True]]]), [[3, 4], [[], [1]]])
    check('no batches', solve([]), [[], []])
    check('single domain', solve([[[3], [0, 0], [True, True]]]), [[3], [[0, 0]]])
elif N == 4:
    check('overlapping domains', solve([[[4, 5], [1, 0], [True, True]], [[6, 4], [1, 0], [True, True]]]), [[4, 5, 6], [[1, 0], [0, 2]]])
    check('unused values', solve([[[4, 5, 6], [1], [True]]]), [[4, 5, 6], [[1]]])
    check('nonadjacent duplicate', solve([[[4, 5, 4], [2, 0], [True, True]]]), [[4, 5], [[0, 0]]])
    check('null lanes', solve([[[4, 5], [1, 0], [False, True]]]), [[4, 5], [[None, 0]]])
    check('empty batch', solve([[[4], [], []], [[5], [0], [True]]]), [[4, 5], [[], [1]]])
    check('no batches', solve([]), [[], []])
    check('single domain', solve([[[4], [0, 0], [True, True]]]), [[4], [[0, 0]]])
elif N == 5:
    check('overlapping domains', solve([[[5, 6], [1, 0], [True, True]], [[7, 5], [1, 0], [True, True]]]), [[5, 6, 7], [[1, 0], [0, 2]]])
    check('unused values', solve([[[5, 6, 7], [1], [True]]]), [[5, 6, 7], [[1]]])
    check('nonadjacent duplicate', solve([[[5, 6, 5], [2, 0], [True, True]]]), [[5, 6], [[0, 0]]])
    check('null lanes', solve([[[5, 6], [1, 0], [False, True]]]), [[5, 6], [[None, 0]]])
    check('empty batch', solve([[[5], [], []], [[6], [0], [True]]]), [[5, 6], [[], [1]]])
    check('no batches', solve([]), [[], []])
    check('single domain', solve([[[5], [0, 0], [True, True]]]), [[5], [[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 fixtureActualExpectedOutcome
overlapping domains[[1, 2, 3], [[1, 0], [0, 2]]][[1, 2, 3], [[1, 0], [0, 2]]]Passed
unused values[[1, 2, 3], [[1]]][[1, 2, 3], [[1]]]Passed
nonadjacent duplicate[[1, 2], [[0, 0]]][[1, 2], [[0, 0]]]Passed
null lanes[[1, 2], [[1, 0]]][[1, 2], [[None, 0]]]Failed
empty batch[[1, 2], [[], [1]]][[1, 2], [[], [1]]]Passed
no batches[[], []][[], []]Passed
single domain[[1], [[0, 0]]][[1], [[0, 0]]]Passed

SHA-256 / b78a3b164353cdcebf48621d7ac2e53b8ab153c7b413300b347092e5da0e9689

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(d):
    try:
        merged=[]; batches=[]
        for dictionary,codes,valid in d:
            for value in dictionary:
                if value not in merged: merged.append(value)
            mapping=[merged.index(v) if v in merged else -1 for v in dictionary]
            rewritten=[mapping[c] if valid[i] else 0 for i,c in enumerate(codes)]
            batches.append(rewritten)
        return [merged,batches]
    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('overlapping domains', solve([[[1, 2], [1, 0], [True, True]], [[3, 1], [1, 0], [True, True]]]), [[1, 2, 3], [[1, 0], [0, 2]]])
    check('unused values', solve([[[1, 2, 3], [1], [True]]]), [[1, 2, 3], [[1]]])
    check('nonadjacent duplicate', solve([[[1, 2, 1], [2, 0], [True, True]]]), [[1, 2], [[0, 0]]])
    check('null lanes', solve([[[1, 2], [1, 0], [False, True]]]), [[1, 2], [[None, 0]]])
    check('empty batch', solve([[[1], [], []], [[2], [0], [True]]]), [[1, 2], [[], [1]]])
    check('no batches', solve([]), [[], []])
    check('single domain', solve([[[1], [0, 0], [True, True]]]), [[1], [[0, 0]]])
elif N == 2:
    check('overlapping domains', solve([[[2, 3], [1, 0], [True, True]], [[4, 2], [1, 0], [True, True]]]), [[2, 3, 4], [[1, 0], [0, 2]]])
    check('unused values', solve([[[2, 3, 4], [1], [True]]]), [[2, 3, 4], [[1]]])
    check('nonadjacent duplicate', solve([[[2, 3, 2], [2, 0], [True, True]]]), [[2, 3], [[0, 0]]])
    check('null lanes', solve([[[2, 3], [1, 0], [False, True]]]), [[2, 3], [[None, 0]]])
    check('empty batch', solve([[[2], [], []], [[3], [0], [True]]]), [[2, 3], [[], [1]]])
    check('no batches', solve([]), [[], []])
    check('single domain', solve([[[2], [0, 0], [True, True]]]), [[2], [[0, 0]]])
elif N == 3:
    check('overlapping domains', solve([[[3, 4], [1, 0], [True, True]], [[5, 3], [1, 0], [True, True]]]), [[3, 4, 5], [[1, 0], [0, 2]]])
    check('unused values', solve([[[3, 4, 5], [1], [True]]]), [[3, 4, 5], [[1]]])
    check('nonadjacent duplicate', solve([[[3, 4, 3], [2, 0], [True, True]]]), [[3, 4], [[0, 0]]])
    check('null lanes', solve([[[3, 4], [1, 0], [False, True]]]), [[3, 4], [[None, 0]]])
    check('empty batch', solve([[[3], [], []], [[4], [0], [True]]]), [[3, 4], [[], [1]]])
    check('no batches', solve([]), [[], []])
    check('single domain', solve([[[3], [0, 0], [True, True]]]), [[3], [[0, 0]]])
elif N == 4:
    check('overlapping domains', solve([[[4, 5], [1, 0], [True, True]], [[6, 4], [1, 0], [True, True]]]), [[4, 5, 6], [[1, 0], [0, 2]]])
    check('unused values', solve([[[4, 5, 6], [1], [True]]]), [[4, 5, 6], [[1]]])
    check('nonadjacent duplicate', solve([[[4, 5, 4], [2, 0], [True, True]]]), [[4, 5], [[0, 0]]])
    check('null lanes', solve([[[4, 5], [1, 0], [False, True]]]), [[4, 5], [[None, 0]]])
    check('empty batch', solve([[[4], [], []], [[5], [0], [True]]]), [[4, 5], [[], [1]]])
    check('no batches', solve([]), [[], []])
    check('single domain', solve([[[4], [0, 0], [True, True]]]), [[4], [[0, 0]]])
elif N == 5:
    check('overlapping domains', solve([[[5, 6], [1, 0], [True, True]], [[7, 5], [1, 0], [True, True]]]), [[5, 6, 7], [[1, 0], [0, 2]]])
    check('unused values', solve([[[5, 6, 7], [1], [True]]]), [[5, 6, 7], [[1]]])
    check('nonadjacent duplicate', solve([[[5, 6, 5], [2, 0], [True, True]]]), [[5, 6], [[0, 0]]])
    check('null lanes', solve([[[5, 6], [1, 0], [False, True]]]), [[5, 6], [[None, 0]]])
    check('empty batch', solve([[[5], [], []], [[6], [0], [True]]]), [[5, 6], [[], [1]]])
    check('no batches', solve([]), [[], []])
    check('single domain', solve([[[5], [0, 0], [True, True]]]), [[5], [[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 fixtureActualExpectedOutcome
overlapping domains[[1, 2, 3], [[1, 0], [0, 2]]][[1, 2, 3], [[1, 0], [0, 2]]]Passed
unused values[[1, 2, 3], [[1]]][[1, 2, 3], [[1]]]Passed
nonadjacent duplicate[[1, 2], [[0, 0]]][[1, 2], [[0, 0]]]Passed
null lanes[[1, 2], [[0, 0]]][[1, 2], [[None, 0]]]Failed
empty batch[[1, 2], [[], [1]]][[1, 2], [[], [1]]]Passed
no batches[[], []][[], []]Passed
single domain[[1], [[0, 0]]][[1], [[0, 0]]]Passed

SHA-256 / 71d24c869ea556a0231b8312511ee0589c6654f37bbe348d081c6787f5595562

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 7 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

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 2026-09-29T14:44:11.808465+00:00.

Case digest / 0eb0161589c40908de861c188a05eb45dd35ebcbd3e2664a7253ce5c40f99a17