FA-44686 / Data systems / Open access
Retractions carry the new value instead of the old value · case 01
Retractions carry the new value instead of the old value.
ROOT CAUSE
delta-filter-before-after: Retractions carry the new value instead of the old value.
VERIFIED REPAIR
Preserve the stated physical representation and operation order: Convert a sequence of [id,before,after] updates into signed filtered rows, with None denoting absent row. The predicate is value>=cutoff. Emit qualifying before-images negatively before qualifying after-images positively; suppress unchanged qualifying values.
Unsuccessful approach: Using the threshold as a placeholder cannot retract the stored row.
Case contract
Convert a sequence of [id,before,after] updates into signed filtered rows, with None denoting absent row. The predicate is value>=cutoff. Emit qualifying before-images negatively before qualifying after-images positively; suppress unchanged qualifying values.
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:
cutoff,updates=d
out=[]
for ident,before,after in updates:
old=before is not None and before>=cutoff
new=after is not None and after>=cutoff
if old and new and before==after: continue
if old: out.append([ident,after,-1])
if new: out.append([ident,after,1])
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('leaves filter', solve([1, [[7, 3, 0]]]), [[7, 3, -1]])
check('enters filter', solve([1, [[7, 0, 3]]]), [[7, 3, 1]])
check('changes within filter', solve([1, [[7, 2, 3]]]), [[7, 2, -1], [7, 3, 1]])
check('unchanged', solve([1, [[7, 1, 1]]]), [])
check('insert', solve([1, [[7, None, 2]]]), [[7, 2, 1]])
check('delete', solve([1, [[7, 2, None]]]), [[7, 2, -1]])
check('outside both', solve([1, [[7, -1, 0]]]), [])
check('no updates', solve([1, []]), [])
elif N == 2:
check('leaves filter', solve([2, [[7, 4, 1]]]), [[7, 4, -1]])
check('enters filter', solve([2, [[7, 1, 4]]]), [[7, 4, 1]])
check('changes within filter', solve([2, [[7, 3, 4]]]), [[7, 3, -1], [7, 4, 1]])
check('unchanged', solve([2, [[7, 2, 2]]]), [])
check('insert', solve([2, [[7, None, 3]]]), [[7, 3, 1]])
check('delete', solve([2, [[7, 3, None]]]), [[7, 3, -1]])
check('outside both', solve([2, [[7, 0, 1]]]), [])
check('no updates', solve([2, []]), [])
elif N == 3:
check('leaves filter', solve([3, [[7, 5, 2]]]), [[7, 5, -1]])
check('enters filter', solve([3, [[7, 2, 5]]]), [[7, 5, 1]])
check('changes within filter', solve([3, [[7, 4, 5]]]), [[7, 4, -1], [7, 5, 1]])
check('unchanged', solve([3, [[7, 3, 3]]]), [])
check('insert', solve([3, [[7, None, 4]]]), [[7, 4, 1]])
check('delete', solve([3, [[7, 4, None]]]), [[7, 4, -1]])
check('outside both', solve([3, [[7, 1, 2]]]), [])
check('no updates', solve([3, []]), [])
elif N == 4:
check('leaves filter', solve([4, [[7, 6, 3]]]), [[7, 6, -1]])
check('enters filter', solve([4, [[7, 3, 6]]]), [[7, 6, 1]])
check('changes within filter', solve([4, [[7, 5, 6]]]), [[7, 5, -1], [7, 6, 1]])
check('unchanged', solve([4, [[7, 4, 4]]]), [])
check('insert', solve([4, [[7, None, 5]]]), [[7, 5, 1]])
check('delete', solve([4, [[7, 5, None]]]), [[7, 5, -1]])
check('outside both', solve([4, [[7, 2, 3]]]), [])
check('no updates', solve([4, []]), [])
elif N == 5:
check('leaves filter', solve([5, [[7, 7, 4]]]), [[7, 7, -1]])
check('enters filter', solve([5, [[7, 4, 7]]]), [[7, 7, 1]])
check('changes within filter', solve([5, [[7, 6, 7]]]), [[7, 6, -1], [7, 7, 1]])
check('unchanged', solve([5, [[7, 5, 5]]]), [])
check('insert', solve([5, [[7, None, 6]]]), [[7, 6, 1]])
check('delete', solve([5, [[7, 6, None]]]), [[7, 6, -1]])
check('outside both', solve([5, [[7, 3, 4]]]), [])
check('no updates', solve([5, []]), [])
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 |
|---|---|---|---|
| leaves filter | [[7, 0, -1]] | [[7, 3, -1]] | Failed |
| enters filter | [[7, 3, 1]] | [[7, 3, 1]] | Passed |
| changes within filter | [[7, 3, -1], [7, 3, 1]] | [[7, 2, -1], [7, 3, 1]] | Failed |
| unchanged | [] | [] | Passed |
| insert | [[7, 2, 1]] | [[7, 2, 1]] | Passed |
| delete | [[7, None, -1]] | [[7, 2, -1]] | Failed |
| outside both | [] | [] | Passed |
| no updates | [] | [] | Passed |
SHA-256 / d753567c8441496d76eaa785bf76268415040d8fc0eedea68baa4ab01b5b4c7f
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(d):
try:
cutoff,updates=d
out=[]
for ident,before,after in updates:
old=before is not None and before>=cutoff
new=after is not None and after>=cutoff
if old and new and before==after: continue
if old: out.append([ident,cutoff,-1])
if new: out.append([ident,after,1])
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('leaves filter', solve([1, [[7, 3, 0]]]), [[7, 3, -1]])
check('enters filter', solve([1, [[7, 0, 3]]]), [[7, 3, 1]])
check('changes within filter', solve([1, [[7, 2, 3]]]), [[7, 2, -1], [7, 3, 1]])
check('unchanged', solve([1, [[7, 1, 1]]]), [])
check('insert', solve([1, [[7, None, 2]]]), [[7, 2, 1]])
check('delete', solve([1, [[7, 2, None]]]), [[7, 2, -1]])
check('outside both', solve([1, [[7, -1, 0]]]), [])
check('no updates', solve([1, []]), [])
elif N == 2:
check('leaves filter', solve([2, [[7, 4, 1]]]), [[7, 4, -1]])
check('enters filter', solve([2, [[7, 1, 4]]]), [[7, 4, 1]])
check('changes within filter', solve([2, [[7, 3, 4]]]), [[7, 3, -1], [7, 4, 1]])
check('unchanged', solve([2, [[7, 2, 2]]]), [])
check('insert', solve([2, [[7, None, 3]]]), [[7, 3, 1]])
check('delete', solve([2, [[7, 3, None]]]), [[7, 3, -1]])
check('outside both', solve([2, [[7, 0, 1]]]), [])
check('no updates', solve([2, []]), [])
elif N == 3:
check('leaves filter', solve([3, [[7, 5, 2]]]), [[7, 5, -1]])
check('enters filter', solve([3, [[7, 2, 5]]]), [[7, 5, 1]])
check('changes within filter', solve([3, [[7, 4, 5]]]), [[7, 4, -1], [7, 5, 1]])
check('unchanged', solve([3, [[7, 3, 3]]]), [])
check('insert', solve([3, [[7, None, 4]]]), [[7, 4, 1]])
check('delete', solve([3, [[7, 4, None]]]), [[7, 4, -1]])
check('outside both', solve([3, [[7, 1, 2]]]), [])
check('no updates', solve([3, []]), [])
elif N == 4:
check('leaves filter', solve([4, [[7, 6, 3]]]), [[7, 6, -1]])
check('enters filter', solve([4, [[7, 3, 6]]]), [[7, 6, 1]])
check('changes within filter', solve([4, [[7, 5, 6]]]), [[7, 5, -1], [7, 6, 1]])
check('unchanged', solve([4, [[7, 4, 4]]]), [])
check('insert', solve([4, [[7, None, 5]]]), [[7, 5, 1]])
check('delete', solve([4, [[7, 5, None]]]), [[7, 5, -1]])
check('outside both', solve([4, [[7, 2, 3]]]), [])
check('no updates', solve([4, []]), [])
elif N == 5:
check('leaves filter', solve([5, [[7, 7, 4]]]), [[7, 7, -1]])
check('enters filter', solve([5, [[7, 4, 7]]]), [[7, 7, 1]])
check('changes within filter', solve([5, [[7, 6, 7]]]), [[7, 6, -1], [7, 7, 1]])
check('unchanged', solve([5, [[7, 5, 5]]]), [])
check('insert', solve([5, [[7, None, 6]]]), [[7, 6, 1]])
check('delete', solve([5, [[7, 6, None]]]), [[7, 6, -1]])
check('outside both', solve([5, [[7, 3, 4]]]), [])
check('no updates', solve([5, []]), [])
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 |
|---|---|---|---|
| leaves filter | [[7, 1, -1]] | [[7, 3, -1]] | Failed |
| enters filter | [[7, 3, 1]] | [[7, 3, 1]] | Passed |
| changes within filter | [[7, 1, -1], [7, 3, 1]] | [[7, 2, -1], [7, 3, 1]] | Failed |
| unchanged | [] | [] | Passed |
| insert | [[7, 2, 1]] | [[7, 2, 1]] | Passed |
| delete | [[7, 1, -1]] | [[7, 2, -1]] | Failed |
| outside both | [] | [] | Passed |
| no updates | [] | [] | Passed |
SHA-256 / 1ac49ddd7bdf67ad051d38e12b7dcbf1f9296f06c942f9a6f8b8a5fc63cba6cf
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(d):
try:
cutoff,updates=d
out=[]
for ident,before,after in updates:
old=before is not None and before>=cutoff
new=after is not None and after>=cutoff
if old and new and before==after: continue
if old: out.append([ident,before,-1])
if new: out.append([ident,after,1])
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('leaves filter', solve([1, [[7, 3, 0]]]), [[7, 3, -1]])
check('enters filter', solve([1, [[7, 0, 3]]]), [[7, 3, 1]])
check('changes within filter', solve([1, [[7, 2, 3]]]), [[7, 2, -1], [7, 3, 1]])
check('unchanged', solve([1, [[7, 1, 1]]]), [])
check('insert', solve([1, [[7, None, 2]]]), [[7, 2, 1]])
check('delete', solve([1, [[7, 2, None]]]), [[7, 2, -1]])
check('outside both', solve([1, [[7, -1, 0]]]), [])
check('no updates', solve([1, []]), [])
elif N == 2:
check('leaves filter', solve([2, [[7, 4, 1]]]), [[7, 4, -1]])
check('enters filter', solve([2, [[7, 1, 4]]]), [[7, 4, 1]])
check('changes within filter', solve([2, [[7, 3, 4]]]), [[7, 3, -1], [7, 4, 1]])
check('unchanged', solve([2, [[7, 2, 2]]]), [])
check('insert', solve([2, [[7, None, 3]]]), [[7, 3, 1]])
check('delete', solve([2, [[7, 3, None]]]), [[7, 3, -1]])
check('outside both', solve([2, [[7, 0, 1]]]), [])
check('no updates', solve([2, []]), [])
elif N == 3:
check('leaves filter', solve([3, [[7, 5, 2]]]), [[7, 5, -1]])
check('enters filter', solve([3, [[7, 2, 5]]]), [[7, 5, 1]])
check('changes within filter', solve([3, [[7, 4, 5]]]), [[7, 4, -1], [7, 5, 1]])
check('unchanged', solve([3, [[7, 3, 3]]]), [])
check('insert', solve([3, [[7, None, 4]]]), [[7, 4, 1]])
check('delete', solve([3, [[7, 4, None]]]), [[7, 4, -1]])
check('outside both', solve([3, [[7, 1, 2]]]), [])
check('no updates', solve([3, []]), [])
elif N == 4:
check('leaves filter', solve([4, [[7, 6, 3]]]), [[7, 6, -1]])
check('enters filter', solve([4, [[7, 3, 6]]]), [[7, 6, 1]])
check('changes within filter', solve([4, [[7, 5, 6]]]), [[7, 5, -1], [7, 6, 1]])
check('unchanged', solve([4, [[7, 4, 4]]]), [])
check('insert', solve([4, [[7, None, 5]]]), [[7, 5, 1]])
check('delete', solve([4, [[7, 5, None]]]), [[7, 5, -1]])
check('outside both', solve([4, [[7, 2, 3]]]), [])
check('no updates', solve([4, []]), [])
elif N == 5:
check('leaves filter', solve([5, [[7, 7, 4]]]), [[7, 7, -1]])
check('enters filter', solve([5, [[7, 4, 7]]]), [[7, 7, 1]])
check('changes within filter', solve([5, [[7, 6, 7]]]), [[7, 6, -1], [7, 7, 1]])
check('unchanged', solve([5, [[7, 5, 5]]]), [])
check('insert', solve([5, [[7, None, 6]]]), [[7, 6, 1]])
check('delete', solve([5, [[7, 6, None]]]), [[7, 6, -1]])
check('outside both', solve([5, [[7, 3, 4]]]), [])
check('no updates', solve([5, []]), [])
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 |
|---|---|---|---|
| leaves filter | [[7, 3, -1]] | [[7, 3, -1]] | Passed |
| enters filter | [[7, 3, 1]] | [[7, 3, 1]] | Passed |
| changes within filter | [[7, 2, -1], [7, 3, 1]] | [[7, 2, -1], [7, 3, 1]] | Passed |
| unchanged | [] | [] | Passed |
| insert | [[7, 2, 1]] | [[7, 2, 1]] | Passed |
| delete | [[7, 2, -1]] | [[7, 2, -1]] | Passed |
| outside both | [] | [] | Passed |
| no updates | [] | [] | Passed |
SHA-256 / 71dda46965c5caa77387ac9c5ab7bef3b013f9119499afa2e1cf8deab0fd8179
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 2026-09-29T14:44:14.562697+00:00.
Case digest / 56040a7e42272815e59abfc79c43d031b1914f2f14fdba2b28737943e948b8f3