FAILURE MAP
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FA-17656 / Time representation / Open access

New branch excludes its first instant · case 01

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

Verified by executionVariant 1 · 11 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

New branch excludes its first instant.

THE FAILURE

New branch excludes its first instant.

Unsuccessful approach: The partial correction still substitutes r['local'] >= r['transition'] 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 = 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 fixtureActualExpectedOutcome
fixture 1[[89], False, 89, 20, 109][[89], False, 89, 20, 109]Passed
fixture 2[[90], False, 90, 20, 110][[90, 100], True, 90, 20, 110]Failed
fixture 3[[90], False, 90, 20, 110][[90, 100], True, 100, 10, 110]Failed
fixture 4[[90], False, 90, 20, 110][[90, 100], True, None, None, None]Failed
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], False, 90, 20, 110][[90, 100], True, 90, 20, 110]Failed

SHA-256 / 9c59c1388029fbf8fe6f7a72244d5a5b451f39978f6b984c746dabaa24c7041a

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 = r['local'] >= 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 fixtureActualExpectedOutcome
fixture 1[[89, 99], True, 89, 20, 109][[89], False, 89, 20, 109]Failed
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, 90], True, 90, 20, 110][[80], False, 80, 20, 100]Failed
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 / 8a2be9553ce5aed5bcb8340ebbd51021d3d6491d885a2c80b19f99a8e15c467a

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 11 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

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 / 02f6de920dd47441952e59969f4388b066405d6b0612ce8826a4bf71eb968826