FA-45586 / Data systems / Open access
A dependent default writes only its constant without reading the source · case 01
A dependent default writes only its constant without reading the source.
ROOT CAUSE
default-column-dependencies: A dependent default writes only its constant without reading the source.
THE FAILURE
default-column-dependencies: A dependent default writes only its constant without reading the source.
Unsuccessful approach: Ignoring the increment instead still does not evaluate the dependent expression.
Case contract
Materialize missing columns using ordered default rules [target,source-or-None,constant]. A constant rule writes constant; a dependent rule writes source+constant, propagating explicit null. Existing columns including None and zero never change. Resolve forward dependencies to a fixed point; unresolved dependencies return DEFAULT_CYCLE.
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:
row,rules=d
result=dict(row)
pending=[rule for rule in rules if rule[0] not in result]
while pending:
progressed=False; later=[]
for target,source,constant in pending:
if source is not None and source not in result:
later.append([target,source,constant]); continue
result[target]=constant if source is None else (None if result[source] is None else constant)
progressed=True
if not progressed: return 'DEFAULT_CYCLE'
pending=later
return result
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('forward dependency', solve([{}, [['b', 'a', 2], ['a', None, 1]]]), {'a': 1, 'b': 3})
check('explicit null', solve([{'a': None}, [['a', None, 1], ['b', 'a', 1]]]), {'a': None, 'b': None})
check('explicit zero', solve([{'a': 0}, [['a', None, 1], ['b', 'a', 2]]]), {'a': 0, 'b': 2})
check('dependency cycle', solve([{}, [['a', 'b', 1], ['b', 'a', 1]]]), 'DEFAULT_CYCLE')
check('provided unrelated', solve([{'x': 1}, [['a', None, 2]]]), {'x': 1, 'a': 2})
check('source provided', solve([{'a': 1}, [['b', 'a', 3]]]), {'a': 1, 'b': 4})
check('no defaults', solve([{'a': 1}, []]), {'a': 1})
elif N == 2:
check('forward dependency', solve([{}, [['b', 'a', 2], ['a', None, 2]]]), {'a': 2, 'b': 4})
check('explicit null', solve([{'a': None}, [['a', None, 2], ['b', 'a', 1]]]), {'a': None, 'b': None})
check('explicit zero', solve([{'a': 0}, [['a', None, 2], ['b', 'a', 2]]]), {'a': 0, 'b': 2})
check('dependency cycle', solve([{}, [['a', 'b', 1], ['b', 'a', 1]]]), 'DEFAULT_CYCLE')
check('provided unrelated', solve([{'x': 2}, [['a', None, 3]]]), {'x': 2, 'a': 3})
check('source provided', solve([{'a': 2}, [['b', 'a', 3]]]), {'a': 2, 'b': 5})
check('no defaults', solve([{'a': 2}, []]), {'a': 2})
elif N == 3:
check('forward dependency', solve([{}, [['b', 'a', 2], ['a', None, 3]]]), {'a': 3, 'b': 5})
check('explicit null', solve([{'a': None}, [['a', None, 3], ['b', 'a', 1]]]), {'a': None, 'b': None})
check('explicit zero', solve([{'a': 0}, [['a', None, 3], ['b', 'a', 2]]]), {'a': 0, 'b': 2})
check('dependency cycle', solve([{}, [['a', 'b', 1], ['b', 'a', 1]]]), 'DEFAULT_CYCLE')
check('provided unrelated', solve([{'x': 3}, [['a', None, 4]]]), {'x': 3, 'a': 4})
check('source provided', solve([{'a': 3}, [['b', 'a', 3]]]), {'a': 3, 'b': 6})
check('no defaults', solve([{'a': 3}, []]), {'a': 3})
elif N == 4:
check('forward dependency', solve([{}, [['b', 'a', 2], ['a', None, 4]]]), {'a': 4, 'b': 6})
check('explicit null', solve([{'a': None}, [['a', None, 4], ['b', 'a', 1]]]), {'a': None, 'b': None})
check('explicit zero', solve([{'a': 0}, [['a', None, 4], ['b', 'a', 2]]]), {'a': 0, 'b': 2})
check('dependency cycle', solve([{}, [['a', 'b', 1], ['b', 'a', 1]]]), 'DEFAULT_CYCLE')
check('provided unrelated', solve([{'x': 4}, [['a', None, 5]]]), {'x': 4, 'a': 5})
check('source provided', solve([{'a': 4}, [['b', 'a', 3]]]), {'a': 4, 'b': 7})
check('no defaults', solve([{'a': 4}, []]), {'a': 4})
elif N == 5:
check('forward dependency', solve([{}, [['b', 'a', 2], ['a', None, 5]]]), {'a': 5, 'b': 7})
check('explicit null', solve([{'a': None}, [['a', None, 5], ['b', 'a', 1]]]), {'a': None, 'b': None})
check('explicit zero', solve([{'a': 0}, [['a', None, 5], ['b', 'a', 2]]]), {'a': 0, 'b': 2})
check('dependency cycle', solve([{}, [['a', 'b', 1], ['b', 'a', 1]]]), 'DEFAULT_CYCLE')
check('provided unrelated', solve([{'x': 5}, [['a', None, 6]]]), {'x': 5, 'a': 6})
check('source provided', solve([{'a': 5}, [['b', 'a', 3]]]), {'a': 5, 'b': 8})
check('no defaults', solve([{'a': 5}, []]), {'a': 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 |
|---|---|---|---|
| forward dependency | {'a': 1, 'b': 2} | {'a': 1, 'b': 3} | Failed |
| explicit null | {'a': None, 'b': None} | {'a': None, 'b': None} | Passed |
| explicit zero | {'a': 0, 'b': 2} | {'a': 0, 'b': 2} | Passed |
| dependency cycle | DEFAULT_CYCLE | DEFAULT_CYCLE | Passed |
| provided unrelated | {'a': 2, 'x': 1} | {'a': 2, 'x': 1} | Passed |
| source provided | {'a': 1, 'b': 3} | {'a': 1, 'b': 4} | Failed |
| no defaults | {'a': 1} | {'a': 1} | Passed |
SHA-256 / 6581e4269896f40cbd55f5ed62ab0c63bd2cc820f90ba2a91331a1bbd00a5f38
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(d):
try:
row,rules=d
result=dict(row)
pending=[rule for rule in rules if rule[0] not in result]
while pending:
progressed=False; later=[]
for target,source,constant in pending:
if source is not None and source not in result:
later.append([target,source,constant]); continue
result[target]=constant if source is None else (None if result[source] is None else result[source])
progressed=True
if not progressed: return 'DEFAULT_CYCLE'
pending=later
return result
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('forward dependency', solve([{}, [['b', 'a', 2], ['a', None, 1]]]), {'a': 1, 'b': 3})
check('explicit null', solve([{'a': None}, [['a', None, 1], ['b', 'a', 1]]]), {'a': None, 'b': None})
check('explicit zero', solve([{'a': 0}, [['a', None, 1], ['b', 'a', 2]]]), {'a': 0, 'b': 2})
check('dependency cycle', solve([{}, [['a', 'b', 1], ['b', 'a', 1]]]), 'DEFAULT_CYCLE')
check('provided unrelated', solve([{'x': 1}, [['a', None, 2]]]), {'x': 1, 'a': 2})
check('source provided', solve([{'a': 1}, [['b', 'a', 3]]]), {'a': 1, 'b': 4})
check('no defaults', solve([{'a': 1}, []]), {'a': 1})
elif N == 2:
check('forward dependency', solve([{}, [['b', 'a', 2], ['a', None, 2]]]), {'a': 2, 'b': 4})
check('explicit null', solve([{'a': None}, [['a', None, 2], ['b', 'a', 1]]]), {'a': None, 'b': None})
check('explicit zero', solve([{'a': 0}, [['a', None, 2], ['b', 'a', 2]]]), {'a': 0, 'b': 2})
check('dependency cycle', solve([{}, [['a', 'b', 1], ['b', 'a', 1]]]), 'DEFAULT_CYCLE')
check('provided unrelated', solve([{'x': 2}, [['a', None, 3]]]), {'x': 2, 'a': 3})
check('source provided', solve([{'a': 2}, [['b', 'a', 3]]]), {'a': 2, 'b': 5})
check('no defaults', solve([{'a': 2}, []]), {'a': 2})
elif N == 3:
check('forward dependency', solve([{}, [['b', 'a', 2], ['a', None, 3]]]), {'a': 3, 'b': 5})
check('explicit null', solve([{'a': None}, [['a', None, 3], ['b', 'a', 1]]]), {'a': None, 'b': None})
check('explicit zero', solve([{'a': 0}, [['a', None, 3], ['b', 'a', 2]]]), {'a': 0, 'b': 2})
check('dependency cycle', solve([{}, [['a', 'b', 1], ['b', 'a', 1]]]), 'DEFAULT_CYCLE')
check('provided unrelated', solve([{'x': 3}, [['a', None, 4]]]), {'x': 3, 'a': 4})
check('source provided', solve([{'a': 3}, [['b', 'a', 3]]]), {'a': 3, 'b': 6})
check('no defaults', solve([{'a': 3}, []]), {'a': 3})
elif N == 4:
check('forward dependency', solve([{}, [['b', 'a', 2], ['a', None, 4]]]), {'a': 4, 'b': 6})
check('explicit null', solve([{'a': None}, [['a', None, 4], ['b', 'a', 1]]]), {'a': None, 'b': None})
check('explicit zero', solve([{'a': 0}, [['a', None, 4], ['b', 'a', 2]]]), {'a': 0, 'b': 2})
check('dependency cycle', solve([{}, [['a', 'b', 1], ['b', 'a', 1]]]), 'DEFAULT_CYCLE')
check('provided unrelated', solve([{'x': 4}, [['a', None, 5]]]), {'x': 4, 'a': 5})
check('source provided', solve([{'a': 4}, [['b', 'a', 3]]]), {'a': 4, 'b': 7})
check('no defaults', solve([{'a': 4}, []]), {'a': 4})
elif N == 5:
check('forward dependency', solve([{}, [['b', 'a', 2], ['a', None, 5]]]), {'a': 5, 'b': 7})
check('explicit null', solve([{'a': None}, [['a', None, 5], ['b', 'a', 1]]]), {'a': None, 'b': None})
check('explicit zero', solve([{'a': 0}, [['a', None, 5], ['b', 'a', 2]]]), {'a': 0, 'b': 2})
check('dependency cycle', solve([{}, [['a', 'b', 1], ['b', 'a', 1]]]), 'DEFAULT_CYCLE')
check('provided unrelated', solve([{'x': 5}, [['a', None, 6]]]), {'x': 5, 'a': 6})
check('source provided', solve([{'a': 5}, [['b', 'a', 3]]]), {'a': 5, 'b': 8})
check('no defaults', solve([{'a': 5}, []]), {'a': 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 |
|---|---|---|---|
| forward dependency | {'a': 1, 'b': 1} | {'a': 1, 'b': 3} | Failed |
| explicit null | {'a': None, 'b': None} | {'a': None, 'b': None} | Passed |
| explicit zero | {'a': 0, 'b': 0} | {'a': 0, 'b': 2} | Failed |
| dependency cycle | DEFAULT_CYCLE | DEFAULT_CYCLE | Passed |
| provided unrelated | {'a': 2, 'x': 1} | {'a': 2, 'x': 1} | Passed |
| source provided | {'a': 1, 'b': 1} | {'a': 1, 'b': 4} | Failed |
| no defaults | {'a': 1} | {'a': 1} | Passed |
SHA-256 / c8e168fcf6278bd75ec9363a023d213c3ac26693941bf57939bff2332d475675
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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Sign in to the archive ↗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 2026-09-29T14:44:23.812041+00:00.
Case digest / 53a79480499c35e7facd27ed7fafda36a7f0fa27770dbdb15a642f2eb5fe284c