FA-17686 / Time representation / Open access
Civil roundtrip subtracts the selected zone offset · case 01
The decoded time state disagrees with the explicit regression oracle for roundtrip.
ROOT CAUSE
Civil roundtrip subtracts the selected zone offset.
VERIFIED REPAIR
Preserve the declared coordinate and state contract at roundtrip: roundtrip = None if chosen is None else chosen + offset.
Unsuccessful approach: The partial correction still substitutes None if chosen is None else chosen - offset at the same fault site.
Case contract
A stipulated backward offset transition at UTC T changes larger old offset to smaller new offset. Candidate UTC coordinates local-offset are admitted on their owning sides (<T old, >=T new). Return sorted unique candidates, ambiguity flag, selected instant under earlier/later/reject policy, selected offset and civil roundtrip. No timezone database is modeled.
Why this case matters
Clock transfer and timestamp consumers require preserved coordinate, phase, validity and elapsed-time semantics.
1 / The failure
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
N = 1
observations = []
def solve(r):
old_candidate = r['local'] - r['old']
new_candidate = r['local'] - r['new']
old_valid = old_candidate < r['transition']
new_valid = new_candidate >= r['transition']
candidates = sorted(set(([old_candidate] if old_valid else []) + ([new_candidate] if new_valid else [])))
count = len(candidates)
ambiguous = count == 2
chosen = None if count == 0 or (ambiguous and r['policy'] == 'reject') else candidates[-1 if r['policy'] == 'later' else 0]
offset = None if chosen is None else (r['old'] if chosen < r['transition'] else r['new'])
roundtrip = chosen
return [candidates,ambiguous,chosen,offset,roundtrip]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve({'local': 109, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}), [[89], False, 89, 20, 109])
check('fixture 2', solve({'local': 110, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}), [[90, 100], True, 90, 20, 110])
check('fixture 3', solve({'local': 110, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'later'}), [[90, 100], True, 100, 10, 110])
check('fixture 4', solve({'local': 110, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'reject'}), [[90, 100], True, None, None, None])
check('fixture 5', solve({'local': 119, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'later'}), [[99, 109], True, 109, 10, 119])
check('fixture 6', solve({'local': 120, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}), [[110], False, 110, 10, 120])
check('fixture 7', solve({'local': 100, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'later'}), [[80], False, 80, 20, 100])
check('fixture 8', solve({'local': 130, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'reject'}), [[120], False, 120, 10, 130])
check('fixture 9', solve({'local': -20, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}), [[-40], False, -40, 20, -20])
check('fixture 10', solve({'local': 115, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'later'}), [[95, 105], True, 105, 10, 115])
variant = [({'local': 110, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}, [[90, 100], True, 90, 20, 110]), ({'local': 111, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}, [[91, 101], True, 91, 20, 111]), ({'local': 112, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}, [[92, 102], True, 92, 20, 112]), ({'local': 113, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}, [[93, 103], True, 93, 20, 113]), ({'local': 114, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}, [[94, 104], True, 94, 20, 114])]
check("variant capture", solve(variant[N-1][0]), variant[N-1][1])
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 |
|---|---|---|---|
| fixture 1 | [[89], False, 89, 20, 89] | [[89], False, 89, 20, 109] | Failed |
| fixture 2 | [[90, 100], True, 90, 20, 90] | [[90, 100], True, 90, 20, 110] | Failed |
| fixture 3 | [[90, 100], True, 100, 10, 100] | [[90, 100], True, 100, 10, 110] | Failed |
| fixture 4 | [[90, 100], True, None, None, None] | [[90, 100], True, None, None, None] | Passed |
| fixture 5 | [[99, 109], True, 109, 10, 109] | [[99, 109], True, 109, 10, 119] | Failed |
| fixture 6 | [[110], False, 110, 10, 110] | [[110], False, 110, 10, 120] | Failed |
| fixture 7 | [[80], False, 80, 20, 80] | [[80], False, 80, 20, 100] | Failed |
| fixture 8 | [[120], False, 120, 10, 120] | [[120], False, 120, 10, 130] | Failed |
| fixture 9 | [[-40], False, -40, 20, -40] | [[-40], False, -40, 20, -20] | Failed |
| fixture 10 | [[95, 105], True, 105, 10, 105] | [[95, 105], True, 105, 10, 115] | Failed |
| variant capture | [[90, 100], True, 90, 20, 90] | [[90, 100], True, 90, 20, 110] | Failed |
SHA-256 / ff267f29d38c28858883cfd938466dfebd697818c5897992ff9f069e4e4c7c63
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
N = 1
observations = []
def solve(r):
old_candidate = r['local'] - r['old']
new_candidate = r['local'] - r['new']
old_valid = old_candidate < r['transition']
new_valid = new_candidate >= r['transition']
candidates = sorted(set(([old_candidate] if old_valid else []) + ([new_candidate] if new_valid else [])))
count = len(candidates)
ambiguous = count == 2
chosen = None if count == 0 or (ambiguous and r['policy'] == 'reject') else candidates[-1 if r['policy'] == 'later' else 0]
offset = None if chosen is None else (r['old'] if chosen < r['transition'] else r['new'])
roundtrip = None if chosen is None else chosen - offset
return [candidates,ambiguous,chosen,offset,roundtrip]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve({'local': 109, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}), [[89], False, 89, 20, 109])
check('fixture 2', solve({'local': 110, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}), [[90, 100], True, 90, 20, 110])
check('fixture 3', solve({'local': 110, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'later'}), [[90, 100], True, 100, 10, 110])
check('fixture 4', solve({'local': 110, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'reject'}), [[90, 100], True, None, None, None])
check('fixture 5', solve({'local': 119, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'later'}), [[99, 109], True, 109, 10, 119])
check('fixture 6', solve({'local': 120, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}), [[110], False, 110, 10, 120])
check('fixture 7', solve({'local': 100, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'later'}), [[80], False, 80, 20, 100])
check('fixture 8', solve({'local': 130, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'reject'}), [[120], False, 120, 10, 130])
check('fixture 9', solve({'local': -20, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}), [[-40], False, -40, 20, -20])
check('fixture 10', solve({'local': 115, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'later'}), [[95, 105], True, 105, 10, 115])
variant = [({'local': 110, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}, [[90, 100], True, 90, 20, 110]), ({'local': 111, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}, [[91, 101], True, 91, 20, 111]), ({'local': 112, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}, [[92, 102], True, 92, 20, 112]), ({'local': 113, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}, [[93, 103], True, 93, 20, 113]), ({'local': 114, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}, [[94, 104], True, 94, 20, 114])]
check("variant capture", solve(variant[N-1][0]), variant[N-1][1])
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 |
|---|---|---|---|
| fixture 1 | [[89], False, 89, 20, 69] | [[89], False, 89, 20, 109] | Failed |
| fixture 2 | [[90, 100], True, 90, 20, 70] | [[90, 100], True, 90, 20, 110] | Failed |
| fixture 3 | [[90, 100], True, 100, 10, 90] | [[90, 100], True, 100, 10, 110] | Failed |
| fixture 4 | [[90, 100], True, None, None, None] | [[90, 100], True, None, None, None] | Passed |
| fixture 5 | [[99, 109], True, 109, 10, 99] | [[99, 109], True, 109, 10, 119] | Failed |
| fixture 6 | [[110], False, 110, 10, 100] | [[110], False, 110, 10, 120] | Failed |
| fixture 7 | [[80], False, 80, 20, 60] | [[80], False, 80, 20, 100] | Failed |
| fixture 8 | [[120], False, 120, 10, 110] | [[120], False, 120, 10, 130] | Failed |
| fixture 9 | [[-40], False, -40, 20, -60] | [[-40], False, -40, 20, -20] | Failed |
| fixture 10 | [[95, 105], True, 105, 10, 95] | [[95, 105], True, 105, 10, 115] | Failed |
| variant capture | [[90, 100], True, 90, 20, 70] | [[90, 100], True, 90, 20, 110] | Failed |
SHA-256 / dbbbff304af0d140fb8ca83a35d29922198740807641e4bb557ec99fb74f637a
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
N = 1
observations = []
def solve(r):
old_candidate = r['local'] - r['old']
new_candidate = r['local'] - r['new']
old_valid = old_candidate < r['transition']
new_valid = new_candidate >= r['transition']
candidates = sorted(set(([old_candidate] if old_valid else []) + ([new_candidate] if new_valid else [])))
count = len(candidates)
ambiguous = count == 2
chosen = None if count == 0 or (ambiguous and r['policy'] == 'reject') else candidates[-1 if r['policy'] == 'later' else 0]
offset = None if chosen is None else (r['old'] if chosen < r['transition'] else r['new'])
roundtrip = None if chosen is None else chosen + offset
return [candidates,ambiguous,chosen,offset,roundtrip]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve({'local': 109, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}), [[89], False, 89, 20, 109])
check('fixture 2', solve({'local': 110, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}), [[90, 100], True, 90, 20, 110])
check('fixture 3', solve({'local': 110, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'later'}), [[90, 100], True, 100, 10, 110])
check('fixture 4', solve({'local': 110, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'reject'}), [[90, 100], True, None, None, None])
check('fixture 5', solve({'local': 119, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'later'}), [[99, 109], True, 109, 10, 119])
check('fixture 6', solve({'local': 120, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}), [[110], False, 110, 10, 120])
check('fixture 7', solve({'local': 100, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'later'}), [[80], False, 80, 20, 100])
check('fixture 8', solve({'local': 130, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'reject'}), [[120], False, 120, 10, 130])
check('fixture 9', solve({'local': -20, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}), [[-40], False, -40, 20, -20])
check('fixture 10', solve({'local': 115, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'later'}), [[95, 105], True, 105, 10, 115])
variant = [({'local': 110, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}, [[90, 100], True, 90, 20, 110]), ({'local': 111, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}, [[91, 101], True, 91, 20, 111]), ({'local': 112, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}, [[92, 102], True, 92, 20, 112]), ({'local': 113, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}, [[93, 103], True, 93, 20, 113]), ({'local': 114, 'old': 20, 'new': 10, 'transition': 100, 'policy': 'earlier'}, [[94, 104], True, 94, 20, 114])]
check("variant capture", solve(variant[N-1][0]), variant[N-1][1])
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 |
|---|---|---|---|
| fixture 1 | [[89], False, 89, 20, 109] | [[89], False, 89, 20, 109] | Passed |
| fixture 2 | [[90, 100], True, 90, 20, 110] | [[90, 100], True, 90, 20, 110] | Passed |
| fixture 3 | [[90, 100], True, 100, 10, 110] | [[90, 100], True, 100, 10, 110] | Passed |
| fixture 4 | [[90, 100], True, None, None, None] | [[90, 100], True, None, None, None] | Passed |
| fixture 5 | [[99, 109], True, 109, 10, 119] | [[99, 109], True, 109, 10, 119] | Passed |
| fixture 6 | [[110], False, 110, 10, 120] | [[110], False, 110, 10, 120] | Passed |
| fixture 7 | [[80], False, 80, 20, 100] | [[80], False, 80, 20, 100] | Passed |
| fixture 8 | [[120], False, 120, 10, 130] | [[120], False, 120, 10, 130] | Passed |
| fixture 9 | [[-40], False, -40, 20, -20] | [[-40], False, -40, 20, -20] | Passed |
| fixture 10 | [[95, 105], True, 105, 10, 115] | [[95, 105], True, 105, 10, 115] | Passed |
| variant capture | [[90, 100], True, 90, 20, 110] | [[90, 100], True, 90, 20, 110] | Passed |
SHA-256 / d21c5db944df4d397679661e96bdd23917ab65d501b4d8fcd8f038396d9aa721
Verification & scope
Deterministic integer reference model with stipulated units and policies; not a complete clock, wire standard or platform implementation. 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 2026-09-29T14:39:49.285093+00:00.
Case digest / 4c466d10fcc72bab065c2b2efa506ed49b9765fcd1d00e06f7c88c53e556c299