FA-18431 / Time representation / Open access

Unknown negative-zero offset collapses into known UTC or absorbs positive zero · case 01

The decoded time state disagrees with the explicit regression oracle for unknown.

Verified by executionVariant 1 · 16 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Unknown negative-zero offset collapses into known UTC or absorbs positive zero.

THE FAILURE

Unknown negative-zero offset collapses into known UTC or absorbs positive zero.

Unsuccessful approach: The partial correction still substitutes valid and hour == 0 and minute == 0 at the same fault site.

Case contract

Controlled offset lexeme is Z or signed HH:MM with ASCII digits, hour<=14, minute<=59 and hour14 only minute00. Negative zero means unknown local offset and has no numeric UTC offset; positive zero and Z are known UTC. Return accepted, known, signed minute displacement and original negative-zero marker. No timezone database is consulted.

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):
    text = r['text']
    zulu = text == 'Z'
    shape = len(text) == 6 and text[0] in '+-' and text[3] == ':'
    digits = shape and all('0' <= c <= '9' for c in text[1:3]+text[4:6])
    hour = int(text[1:3]) if digits else 0
    minute = int(text[4:6]) if digits else 0
    range_ok = hour <= 14 and minute <= 59 and (hour != 14 or minute == 0)
    valid = zulu or (digits and range_ok)
    unknown = False
    offset = None if not valid or unknown else (0 if zulu else (-1 if text[0] == '-' else 1) * (hour * 60 + minute))
    return [valid,valid and not unknown,offset,unknown]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve({'text': 'Z', 'probe': 0}), [True, True, 0, False])
check('fixture 2', solve({'text': 'z', 'probe': 0}), [False, False, None, False])
check('fixture 3', solve({'text': 'UTC', 'probe': 0}), [False, False, None, False])
check('fixture 4', solve({'text': '+00:00', 'probe': 0}), [True, True, 0, False])
check('fixture 5', solve({'text': '-00:00', 'probe': 0}), [True, False, None, True])
check('fixture 6', solve({'text': '-05:30', 'probe': 0}), [True, True, -330, False])
check('fixture 7', solve({'text': '+14:00', 'probe': 0}), [True, True, 840, False])
check('fixture 8', solve({'text': '+14:01', 'probe': 0}), [False, False, None, False])
check('fixture 9', solve({'text': '+12:59', 'probe': 0}), [True, True, 779, False])
check('fixture 10', solve({'text': '+12:60', 'probe': 0}), [False, False, None, False])
check('fixture 11', solve({'text': 'x01:00', 'probe': 0}), [False, False, None, False])
check('fixture 12', solve({'text': '+01x00', 'probe': 0}), [False, False, None, False])
check('fixture 13', solve({'text': '+٠١:٠٠', 'probe': 0}), [False, False, None, False])
check('fixture 14', solve({'text': ' Z ', 'probe': 0}), [False, False, None, False])
check('fixture 15', solve({'text': '+10:02', 'probe': 0}), [True, True, 602, False])
variant = [({'text': '+01:30', 'probe': 0}, [True, True, 90, False]), ({'text': '+02:30', 'probe': 0}, [True, True, 150, False]), ({'text': '+03:30', 'probe': 0}, [True, True, 210, False]), ({'text': '+04:30', 'probe': 0}, [True, True, 270, False]), ({'text': '+05:30', 'probe': 0}, [True, True, 330, False])]
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	`[True, True, 0, False]`	`[True, True, 0, False]`	Passed
fixture 2	`[False, False, None, False]`	`[False, False, None, False]`	Passed
fixture 3	`[False, False, None, False]`	`[False, False, None, False]`	Passed
fixture 4	`[True, True, 0, False]`	`[True, True, 0, False]`	Passed
fixture 5	`[True, True, 0, False]`	`[True, False, None, True]`	Failed
fixture 6	`[True, True, -330, False]`	`[True, True, -330, False]`	Passed
fixture 7	`[True, True, 840, False]`	`[True, True, 840, False]`	Passed
fixture 8	`[False, False, None, False]`	`[False, False, None, False]`	Passed
fixture 9	`[True, True, 779, False]`	`[True, True, 779, False]`	Passed
fixture 10	`[False, False, None, False]`	`[False, False, None, False]`	Passed
fixture 11	`[False, False, None, False]`	`[False, False, None, False]`	Passed
fixture 12	`[False, False, None, False]`	`[False, False, None, False]`	Passed
fixture 13	`[False, False, None, False]`	`[False, False, None, False]`	Passed
fixture 14	`[False, False, None, False]`	`[False, False, None, False]`	Passed
fixture 15	`[True, True, 602, False]`	`[True, True, 602, False]`	Passed
variant capture	`[True, True, 90, False]`	`[True, True, 90, False]`	Passed

SHA-256 / 1f8ccca2c9a0c3984c6bc637def7d1896b4a5bdf0e50c05c206df3d8511c99af

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):
    text = r['text']
    zulu = text == 'Z'
    shape = len(text) == 6 and text[0] in '+-' and text[3] == ':'
    digits = shape and all('0' <= c <= '9' for c in text[1:3]+text[4:6])
    hour = int(text[1:3]) if digits else 0
    minute = int(text[4:6]) if digits else 0
    range_ok = hour <= 14 and minute <= 59 and (hour != 14 or minute == 0)
    valid = zulu or (digits and range_ok)
    unknown = valid and hour == 0 and minute == 0
    offset = None if not valid or unknown else (0 if zulu else (-1 if text[0] == '-' else 1) * (hour * 60 + minute))
    return [valid,valid and not unknown,offset,unknown]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve({'text': 'Z', 'probe': 0}), [True, True, 0, False])
check('fixture 2', solve({'text': 'z', 'probe': 0}), [False, False, None, False])
check('fixture 3', solve({'text': 'UTC', 'probe': 0}), [False, False, None, False])
check('fixture 4', solve({'text': '+00:00', 'probe': 0}), [True, True, 0, False])
check('fixture 5', solve({'text': '-00:00', 'probe': 0}), [True, False, None, True])
check('fixture 6', solve({'text': '-05:30', 'probe': 0}), [True, True, -330, False])
check('fixture 7', solve({'text': '+14:00', 'probe': 0}), [True, True, 840, False])
check('fixture 8', solve({'text': '+14:01', 'probe': 0}), [False, False, None, False])
check('fixture 9', solve({'text': '+12:59', 'probe': 0}), [True, True, 779, False])
check('fixture 10', solve({'text': '+12:60', 'probe': 0}), [False, False, None, False])
check('fixture 11', solve({'text': 'x01:00', 'probe': 0}), [False, False, None, False])
check('fixture 12', solve({'text': '+01x00', 'probe': 0}), [False, False, None, False])
check('fixture 13', solve({'text': '+٠١:٠٠', 'probe': 0}), [False, False, None, False])
check('fixture 14', solve({'text': ' Z ', 'probe': 0}), [False, False, None, False])
check('fixture 15', solve({'text': '+10:02', 'probe': 0}), [True, True, 602, False])
variant = [({'text': '+01:30', 'probe': 0}, [True, True, 90, False]), ({'text': '+02:30', 'probe': 0}, [True, True, 150, False]), ({'text': '+03:30', 'probe': 0}, [True, True, 210, False]), ({'text': '+04:30', 'probe': 0}, [True, True, 270, False]), ({'text': '+05:30', 'probe': 0}, [True, True, 330, False])]
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	`[True, False, None, True]`	`[True, True, 0, False]`	Failed
fixture 2	`[False, False, None, False]`	`[False, False, None, False]`	Passed
fixture 3	`[False, False, None, False]`	`[False, False, None, False]`	Passed
fixture 4	`[True, False, None, True]`	`[True, True, 0, False]`	Failed
fixture 5	`[True, False, None, True]`	`[True, False, None, True]`	Passed
fixture 6	`[True, True, -330, False]`	`[True, True, -330, False]`	Passed
fixture 7	`[True, True, 840, False]`	`[True, True, 840, False]`	Passed
fixture 8	`[False, False, None, False]`	`[False, False, None, False]`	Passed
fixture 9	`[True, True, 779, False]`	`[True, True, 779, False]`	Passed
fixture 10	`[False, False, None, False]`	`[False, False, None, False]`	Passed
fixture 11	`[False, False, None, False]`	`[False, False, None, False]`	Passed
fixture 12	`[False, False, None, False]`	`[False, False, None, False]`	Passed
fixture 13	`[False, False, None, False]`	`[False, False, None, False]`	Passed
fixture 14	`[False, False, None, False]`	`[False, False, None, False]`	Passed
fixture 15	`[True, True, 602, False]`	`[True, True, 602, False]`	Passed
variant capture	`[True, True, 90, False]`	`[True, True, 90, False]`	Passed

SHA-256 / b83e846e49ec2c5ba4e4716abbc5be62060e89fd2527a073284aca23444d1729

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 16 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.

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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 2026-09-29T14:39:57.602371+00:00.

Case digest / 46c28cb246385f7e85fee08a25eae8c9bacf77c87cea694486f735b3a70900dc