FA-3411 / Lexical grammars / Open access

A byte address mixes colon and hyphen separators · case 01

A byte address mixes colon and hyphen separators.

Verified by executionVariant 1 · 4 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The recognizer uses '(?:[0-9A-Fa-f]{2}[:-]){5}[0-9A-Fa-f]{2}', which admits or omits a token shape forbidden by the stated grammar.

VERIFIED REPAIR

Implement the complete stated contract, including the boundary fixtures: Accept six hex octets separated consistently by colons or consistently by hyphens.

Unsuccessful approach: The candidate grammar '(?:[0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}' still disagrees with the explicit boundary fixtures.

Case contract

Accept six hex octets separated consistently by colons or consistently by hyphens.

Why this case matters

A local executable model for consumers of structured text; oracle values are authored literals, not outputs copied from the repaired implementation.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import re, unicodedata, json, csv, io, html, base64, binascii, codecs, struct
from urllib.parse import quote, unquote, unquote_to_bytes, urlencode, parse_qsl, urlsplit, urlunsplit
from email.header import decode_header, make_header
from email.utils import getaddresses
from xml.etree import ElementTree as ET
import shlex, string, textwrap

N = 1
observations = []
def solve(x):
    try:
        return bool(re.fullmatch('(?:[0-9A-Fa-f]{2}[:-]){5}[0-9A-Fa-f]{2}',x))
    except Exception as exc:
        return {"error": type(exc).__name__}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('boundary 1', solve('aa:bb-cc:dd:ee:ff'), False)
check('boundary 2', solve('aa-bb-cc-dd-ee-ff'), True)
check('boundary 3', solve('00:11:22:33:44:55'), True)
check('boundary 4', solve('a:b:c:d:e:f'), False)
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
boundary 1	`True`	`False`	Failed
boundary 2	`True`	`True`	Passed
boundary 3	`True`	`True`	Passed
boundary 4	`False`	`False`	Passed

SHA-256 / 0adf492d5345ffafe995529d0477757899c2d57674b55ddff45d7f1d6bc95fed

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import re, unicodedata, json, csv, io, html, base64, binascii, codecs, struct
from urllib.parse import quote, unquote, unquote_to_bytes, urlencode, parse_qsl, urlsplit, urlunsplit
from email.header import decode_header, make_header
from email.utils import getaddresses
from xml.etree import ElementTree as ET
import shlex, string, textwrap

N = 1
observations = []
def solve(x):
    try:
        return bool(re.fullmatch('(?:[0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}',x))
    except Exception as exc:
        return {"error": type(exc).__name__}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('boundary 1', solve('aa:bb-cc:dd:ee:ff'), False)
check('boundary 2', solve('aa-bb-cc-dd-ee-ff'), True)
check('boundary 3', solve('00:11:22:33:44:55'), True)
check('boundary 4', solve('a:b:c:d:e:f'), False)
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
boundary 1	`False`	`False`	Passed
boundary 2	`False`	`True`	Failed
boundary 3	`True`	`True`	Passed
boundary 4	`False`	`False`	Passed

SHA-256 / 485fc321717c282400b05f8153cae19be4245dc4fc045f65bb051d1ff412a52d

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
import re, unicodedata, json, csv, io, html, base64, binascii, codecs, struct
from urllib.parse import quote, unquote, unquote_to_bytes, urlencode, parse_qsl, urlsplit, urlunsplit
from email.header import decode_header, make_header
from email.utils import getaddresses
from xml.etree import ElementTree as ET
import shlex, string, textwrap

N = 1
observations = []
def solve(x):
    try:
        return bool(re.fullmatch('[0-9A-Fa-f]{2}([:-])(?:[0-9A-Fa-f]{2}\\1){4}[0-9A-Fa-f]{2}',x))
    except Exception as exc:
        return {"error": type(exc).__name__}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('boundary 1', solve('aa:bb-cc:dd:ee:ff'), False)
check('boundary 2', solve('aa-bb-cc-dd-ee-ff'), True)
check('boundary 3', solve('00:11:22:33:44:55'), True)
check('boundary 4', solve('a:b:c:d:e:f'), False)
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
boundary 1	`False`	`False`	Passed
boundary 2	`True`	`True`	Passed
boundary 3	`True`	`True`	Passed
boundary 4	`False`	`False`	Passed

SHA-256 / 9838c5a2c961c7f3478067c7946b4dee0fe25f4ec539c3bdce76b87f880378dc

Verification & scope

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 2026-09-29T14:37:25.437595+00:00.

Case digest / dac3b88e621f21d91a82295f49f577f7440d8a591a1dc21bb7bddac357c83e50