FA-96826 / Phone number formatting / Open access
Caller ID display and callback string: subscriber numbers are called back without the area · case 01
A seven-digit caller is called back as trunk + number.
ROOT CAUSE
The default area is not inserted.
VERIFIED REPAIR
Dial trunk + default area + subscriber number.
Unsuccessful approach: Dialing area + number without the trunk fails from the home network.
Case contract
Home country: trunk 0, code 42, exit 00, default area 55. Restricted -> ["Private", None]; unavailable -> ["Unavailable", None]; no digits -> ["Unknown", None]. For type "unknown": a stripped leading "+" means international, else a leading exit prefix is removed and means international, else a leading trunk is removed and means national, else subscriber. International: display "+digits"; callback is trunk + national part for the home code, otherwise exit + digits. National: trunk + digits for both. Subscriber: display digits, callback trunk + area + digits. Return [display, callback].
Why this case matters
Caller ID is shown on handsets and used for one-touch callback; a wrong classification displays a foreign number as local and calls back the wrong party.
1 / The failure
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(x):
TRUNK, CC, EXIT, AREA = '0', '42', '00', '55'
pres = x.get('presentation', 'allowed')
if pres == 'restricted':
return ['Private', None]
if pres == 'unavailable':
return ['Unavailable', None]
raw = x.get('number') or ''
kind = x.get('type', 'unknown')
digits = ''.join(c for c in raw if c.isdigit())
if not digits:
return ['Unknown', None]
if kind == 'unknown':
if raw.strip().startswith('+'):
kind = 'international'
elif digits.startswith(EXIT):
kind, digits = 'international', digits[len(EXIT):]
elif digits.startswith(TRUNK):
kind, digits = 'national', digits[len(TRUNK):]
else:
kind = 'subscriber'
if kind == 'international':
if digits.startswith(CC):
return ['+' + digits, TRUNK + digits[len(CC):]]
return ['+' + digits, EXIT + digits]
if kind == 'national':
return [TRUNK + digits, TRUNK + digits]
return [digits, TRUNK + digits]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['own-country international number', {'number': '+42555550112', 'type': 'international'}, ['+42555550112', '0555550112']], ['unknown type with padded plus', {'number': ' +83 55501212'}, ['+8355501212', '008355501212']], ['unknown type with exit prefix', {'number': '0083 55501212'}, ['+8355501212', '008355501212']], ['unknown type with trunk', {'number': '0555550112'}, ['0555550112', '0555550112']], ['unknown type starting with the country digits', {'number': '425550112'}, ['425550112', '055425550112']], ['subscriber number', {'number': '5550112'}, ['5550112', '0555550112']], ['declared national number', {'number': '555550112', 'type': 'national'}, ['0555550112', '0555550112']], ['unavailable presentation', {'number': '+42555550112', 'presentation': 'unavailable'}, ['Unavailable', None]], ['allowed but empty', {'number': '', 'presentation': 'allowed'}, ['Unknown', None]], ['punctuation only', {'number': '---'}, ['Unknown', None]], ['restricted without number', {'number': None, 'presentation': 'restricted'}, ['Private', None]]], [['own-country international number', {'number': '+42555550223', 'type': 'international'}, ['+42555550223', '0555550223']], ['unknown type with padded plus', {'number': ' +83 55502323'}, ['+8355502323', '008355502323']], ['unknown type with exit prefix', {'number': '0083 55502323'}, ['+8355502323', '008355502323']], ['unknown type with trunk', {'number': '0555550223'}, ['0555550223', '0555550223']], ['unknown type starting with the country digits', {'number': '425550223'}, ['425550223', '055425550223']], ['subscriber number', {'number': '5550223'}, ['5550223', '0555550223']], ['declared national number', {'number': '555550223', 'type': 'national'}, ['0555550223', '0555550223']], ['unavailable presentation', {'number': '+42555550223', 'presentation': 'unavailable'}, ['Unavailable', None]], ['allowed but empty', {'number': '', 'presentation': 'allowed'}, ['Unknown', None]], ['punctuation only', {'number': '---'}, ['Unknown', None]], ['restricted without number', {'number': None, 'presentation': 'restricted'}, ['Private', None]]], [['own-country international number', {'number': '+42555550334', 'type': 'international'}, ['+42555550334', '0555550334']], ['unknown type with padded plus', {'number': ' +83 55503434'}, ['+8355503434', '008355503434']], ['unknown type with exit prefix', {'number': '0083 55503434'}, ['+8355503434', '008355503434']], ['unknown type with trunk', {'number': '0555550334'}, ['0555550334', '0555550334']], ['unknown type starting with the country digits', {'number': '425550334'}, ['425550334', '055425550334']], ['subscriber number', {'number': '5550334'}, ['5550334', '0555550334']], ['declared national number', {'number': '555550334', 'type': 'national'}, ['0555550334', '0555550334']], ['unavailable presentation', {'number': '+42555550334', 'presentation': 'unavailable'}, ['Unavailable', None]], ['allowed but empty', {'number': '', 'presentation': 'allowed'}, ['Unknown', None]], ['punctuation only', {'number': '---'}, ['Unknown', None]], ['restricted without number', {'number': None, 'presentation': 'restricted'}, ['Private', None]]], [['own-country international number', {'number': '+42555550445', 'type': 'international'}, ['+42555550445', '0555550445']], ['unknown type with padded plus', {'number': ' +83 55504545'}, ['+8355504545', '008355504545']], ['unknown type with exit prefix', {'number': '0083 55504545'}, ['+8355504545', '008355504545']], ['unknown type with trunk', {'number': '0555550445'}, ['0555550445', '0555550445']], ['unknown type starting with the country digits', {'number': '425550445'}, ['425550445', '055425550445']], ['subscriber number', {'number': '5550445'}, ['5550445', '0555550445']], ['declared national number', {'number': '555550445', 'type': 'national'}, ['0555550445', '0555550445']], ['unavailable presentation', {'number': '+42555550445', 'presentation': 'unavailable'}, ['Unavailable', None]], ['allowed but empty', {'number': '', 'presentation': 'allowed'}, ['Unknown', None]], ['punctuation only', {'number': '---'}, ['Unknown', None]], ['restricted without number', {'number': None, 'presentation': 'restricted'}, ['Private', None]]], [['own-country international number', {'number': '+42555550556', 'type': 'international'}, ['+42555550556', '0555550556']], ['unknown type with padded plus', {'number': ' +83 55505656'}, ['+8355505656', '008355505656']], ['unknown type with exit prefix', {'number': '0083 55505656'}, ['+8355505656', '008355505656']], ['unknown type with trunk', {'number': '0555550556'}, ['0555550556', '0555550556']], ['unknown type starting with the country digits', {'number': '425550556'}, ['425550556', '055425550556']], ['subscriber number', {'number': '5550556'}, ['5550556', '0555550556']], ['declared national number', {'number': '555550556', 'type': 'national'}, ['0555550556', '0555550556']], ['unavailable presentation', {'number': '+42555550556', 'presentation': 'unavailable'}, ['Unavailable', None]], ['allowed but empty', {'number': '', 'presentation': 'allowed'}, ['Unknown', None]], ['punctuation only', {'number': '---'}, ['Unknown', None]], ['restricted without number', {'number': None, 'presentation': 'restricted'}, ['Private', None]]]]
for label, arg, expected in fixtures[N - 1]:
check(label, solve(arg), expected)
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 |
|---|---|---|---|
| own-country international number | ['+42555550112', '0555550112'] | ['+42555550112', '0555550112'] | Passed |
| unknown type with padded plus | ['+8355501212', '008355501212'] | ['+8355501212', '008355501212'] | Passed |
| unknown type with exit prefix | ['+8355501212', '008355501212'] | ['+8355501212', '008355501212'] | Passed |
| unknown type with trunk | ['0555550112', '0555550112'] | ['0555550112', '0555550112'] | Passed |
| unknown type starting with the country digits | ['425550112', '0425550112'] | ['425550112', '055425550112'] | Failed |
| subscriber number | ['5550112', '05550112'] | ['5550112', '0555550112'] | Failed |
| declared national number | ['0555550112', '0555550112'] | ['0555550112', '0555550112'] | Passed |
| unavailable presentation | ['Unavailable', None] | ['Unavailable', None] | Passed |
| allowed but empty | ['Unknown', None] | ['Unknown', None] | Passed |
| punctuation only | ['Unknown', None] | ['Unknown', None] | Passed |
| restricted without number | ['Private', None] | ['Private', None] | Passed |
SHA-256 / 3c69ff9395915a96a17512ada894987fa2d1c3e6a4520d23398a2d22ec6d5d6d
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(x):
TRUNK, CC, EXIT, AREA = '0', '42', '00', '55'
pres = x.get('presentation', 'allowed')
if pres == 'restricted':
return ['Private', None]
if pres == 'unavailable':
return ['Unavailable', None]
raw = x.get('number') or ''
kind = x.get('type', 'unknown')
digits = ''.join(c for c in raw if c.isdigit())
if not digits:
return ['Unknown', None]
if kind == 'unknown':
if raw.strip().startswith('+'):
kind = 'international'
elif digits.startswith(EXIT):
kind, digits = 'international', digits[len(EXIT):]
elif digits.startswith(TRUNK):
kind, digits = 'national', digits[len(TRUNK):]
else:
kind = 'subscriber'
if kind == 'international':
if digits.startswith(CC):
return ['+' + digits, TRUNK + digits[len(CC):]]
return ['+' + digits, EXIT + digits]
if kind == 'national':
return [TRUNK + digits, TRUNK + digits]
return [digits, AREA + digits]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['own-country international number', {'number': '+42555550112', 'type': 'international'}, ['+42555550112', '0555550112']], ['unknown type with padded plus', {'number': ' +83 55501212'}, ['+8355501212', '008355501212']], ['unknown type with exit prefix', {'number': '0083 55501212'}, ['+8355501212', '008355501212']], ['unknown type with trunk', {'number': '0555550112'}, ['0555550112', '0555550112']], ['unknown type starting with the country digits', {'number': '425550112'}, ['425550112', '055425550112']], ['subscriber number', {'number': '5550112'}, ['5550112', '0555550112']], ['declared national number', {'number': '555550112', 'type': 'national'}, ['0555550112', '0555550112']], ['unavailable presentation', {'number': '+42555550112', 'presentation': 'unavailable'}, ['Unavailable', None]], ['allowed but empty', {'number': '', 'presentation': 'allowed'}, ['Unknown', None]], ['punctuation only', {'number': '---'}, ['Unknown', None]], ['restricted without number', {'number': None, 'presentation': 'restricted'}, ['Private', None]]], [['own-country international number', {'number': '+42555550223', 'type': 'international'}, ['+42555550223', '0555550223']], ['unknown type with padded plus', {'number': ' +83 55502323'}, ['+8355502323', '008355502323']], ['unknown type with exit prefix', {'number': '0083 55502323'}, ['+8355502323', '008355502323']], ['unknown type with trunk', {'number': '0555550223'}, ['0555550223', '0555550223']], ['unknown type starting with the country digits', {'number': '425550223'}, ['425550223', '055425550223']], ['subscriber number', {'number': '5550223'}, ['5550223', '0555550223']], ['declared national number', {'number': '555550223', 'type': 'national'}, ['0555550223', '0555550223']], ['unavailable presentation', {'number': '+42555550223', 'presentation': 'unavailable'}, ['Unavailable', None]], ['allowed but empty', {'number': '', 'presentation': 'allowed'}, ['Unknown', None]], ['punctuation only', {'number': '---'}, ['Unknown', None]], ['restricted without number', {'number': None, 'presentation': 'restricted'}, ['Private', None]]], [['own-country international number', {'number': '+42555550334', 'type': 'international'}, ['+42555550334', '0555550334']], ['unknown type with padded plus', {'number': ' +83 55503434'}, ['+8355503434', '008355503434']], ['unknown type with exit prefix', {'number': '0083 55503434'}, ['+8355503434', '008355503434']], ['unknown type with trunk', {'number': '0555550334'}, ['0555550334', '0555550334']], ['unknown type starting with the country digits', {'number': '425550334'}, ['425550334', '055425550334']], ['subscriber number', {'number': '5550334'}, ['5550334', '0555550334']], ['declared national number', {'number': '555550334', 'type': 'national'}, ['0555550334', '0555550334']], ['unavailable presentation', {'number': '+42555550334', 'presentation': 'unavailable'}, ['Unavailable', None]], ['allowed but empty', {'number': '', 'presentation': 'allowed'}, ['Unknown', None]], ['punctuation only', {'number': '---'}, ['Unknown', None]], ['restricted without number', {'number': None, 'presentation': 'restricted'}, ['Private', None]]], [['own-country international number', {'number': '+42555550445', 'type': 'international'}, ['+42555550445', '0555550445']], ['unknown type with padded plus', {'number': ' +83 55504545'}, ['+8355504545', '008355504545']], ['unknown type with exit prefix', {'number': '0083 55504545'}, ['+8355504545', '008355504545']], ['unknown type with trunk', {'number': '0555550445'}, ['0555550445', '0555550445']], ['unknown type starting with the country digits', {'number': '425550445'}, ['425550445', '055425550445']], ['subscriber number', {'number': '5550445'}, ['5550445', '0555550445']], ['declared national number', {'number': '555550445', 'type': 'national'}, ['0555550445', '0555550445']], ['unavailable presentation', {'number': '+42555550445', 'presentation': 'unavailable'}, ['Unavailable', None]], ['allowed but empty', {'number': '', 'presentation': 'allowed'}, ['Unknown', None]], ['punctuation only', {'number': '---'}, ['Unknown', None]], ['restricted without number', {'number': None, 'presentation': 'restricted'}, ['Private', None]]], [['own-country international number', {'number': '+42555550556', 'type': 'international'}, ['+42555550556', '0555550556']], ['unknown type with padded plus', {'number': ' +83 55505656'}, ['+8355505656', '008355505656']], ['unknown type with exit prefix', {'number': '0083 55505656'}, ['+8355505656', '008355505656']], ['unknown type with trunk', {'number': '0555550556'}, ['0555550556', '0555550556']], ['unknown type starting with the country digits', {'number': '425550556'}, ['425550556', '055425550556']], ['subscriber number', {'number': '5550556'}, ['5550556', '0555550556']], ['declared national number', {'number': '555550556', 'type': 'national'}, ['0555550556', '0555550556']], ['unavailable presentation', {'number': '+42555550556', 'presentation': 'unavailable'}, ['Unavailable', None]], ['allowed but empty', {'number': '', 'presentation': 'allowed'}, ['Unknown', None]], ['punctuation only', {'number': '---'}, ['Unknown', None]], ['restricted without number', {'number': None, 'presentation': 'restricted'}, ['Private', None]]]]
for label, arg, expected in fixtures[N - 1]:
check(label, solve(arg), expected)
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 |
|---|---|---|---|
| own-country international number | ['+42555550112', '0555550112'] | ['+42555550112', '0555550112'] | Passed |
| unknown type with padded plus | ['+8355501212', '008355501212'] | ['+8355501212', '008355501212'] | Passed |
| unknown type with exit prefix | ['+8355501212', '008355501212'] | ['+8355501212', '008355501212'] | Passed |
| unknown type with trunk | ['0555550112', '0555550112'] | ['0555550112', '0555550112'] | Passed |
| unknown type starting with the country digits | ['425550112', '55425550112'] | ['425550112', '055425550112'] | Failed |
| subscriber number | ['5550112', '555550112'] | ['5550112', '0555550112'] | Failed |
| declared national number | ['0555550112', '0555550112'] | ['0555550112', '0555550112'] | Passed |
| unavailable presentation | ['Unavailable', None] | ['Unavailable', None] | Passed |
| allowed but empty | ['Unknown', None] | ['Unknown', None] | Passed |
| punctuation only | ['Unknown', None] | ['Unknown', None] | Passed |
| restricted without number | ['Private', None] | ['Private', None] | Passed |
SHA-256 / 18e1fbd0a7b4e96ef3edc4357b0b6089973626e57b33fb003c1c008b23fe3893
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(x):
TRUNK, CC, EXIT, AREA = '0', '42', '00', '55'
pres = x.get('presentation', 'allowed')
if pres == 'restricted':
return ['Private', None]
if pres == 'unavailable':
return ['Unavailable', None]
raw = x.get('number') or ''
kind = x.get('type', 'unknown')
digits = ''.join(c for c in raw if c.isdigit())
if not digits:
return ['Unknown', None]
if kind == 'unknown':
if raw.strip().startswith('+'):
kind = 'international'
elif digits.startswith(EXIT):
kind, digits = 'international', digits[len(EXIT):]
elif digits.startswith(TRUNK):
kind, digits = 'national', digits[len(TRUNK):]
else:
kind = 'subscriber'
if kind == 'international':
if digits.startswith(CC):
return ['+' + digits, TRUNK + digits[len(CC):]]
return ['+' + digits, EXIT + digits]
if kind == 'national':
return [TRUNK + digits, TRUNK + digits]
return [digits, TRUNK + AREA + digits]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['own-country international number', {'number': '+42555550112', 'type': 'international'}, ['+42555550112', '0555550112']], ['unknown type with padded plus', {'number': ' +83 55501212'}, ['+8355501212', '008355501212']], ['unknown type with exit prefix', {'number': '0083 55501212'}, ['+8355501212', '008355501212']], ['unknown type with trunk', {'number': '0555550112'}, ['0555550112', '0555550112']], ['unknown type starting with the country digits', {'number': '425550112'}, ['425550112', '055425550112']], ['subscriber number', {'number': '5550112'}, ['5550112', '0555550112']], ['declared national number', {'number': '555550112', 'type': 'national'}, ['0555550112', '0555550112']], ['unavailable presentation', {'number': '+42555550112', 'presentation': 'unavailable'}, ['Unavailable', None]], ['allowed but empty', {'number': '', 'presentation': 'allowed'}, ['Unknown', None]], ['punctuation only', {'number': '---'}, ['Unknown', None]], ['restricted without number', {'number': None, 'presentation': 'restricted'}, ['Private', None]]], [['own-country international number', {'number': '+42555550223', 'type': 'international'}, ['+42555550223', '0555550223']], ['unknown type with padded plus', {'number': ' +83 55502323'}, ['+8355502323', '008355502323']], ['unknown type with exit prefix', {'number': '0083 55502323'}, ['+8355502323', '008355502323']], ['unknown type with trunk', {'number': '0555550223'}, ['0555550223', '0555550223']], ['unknown type starting with the country digits', {'number': '425550223'}, ['425550223', '055425550223']], ['subscriber number', {'number': '5550223'}, ['5550223', '0555550223']], ['declared national number', {'number': '555550223', 'type': 'national'}, ['0555550223', '0555550223']], ['unavailable presentation', {'number': '+42555550223', 'presentation': 'unavailable'}, ['Unavailable', None]], ['allowed but empty', {'number': '', 'presentation': 'allowed'}, ['Unknown', None]], ['punctuation only', {'number': '---'}, ['Unknown', None]], ['restricted without number', {'number': None, 'presentation': 'restricted'}, ['Private', None]]], [['own-country international number', {'number': '+42555550334', 'type': 'international'}, ['+42555550334', '0555550334']], ['unknown type with padded plus', {'number': ' +83 55503434'}, ['+8355503434', '008355503434']], ['unknown type with exit prefix', {'number': '0083 55503434'}, ['+8355503434', '008355503434']], ['unknown type with trunk', {'number': '0555550334'}, ['0555550334', '0555550334']], ['unknown type starting with the country digits', {'number': '425550334'}, ['425550334', '055425550334']], ['subscriber number', {'number': '5550334'}, ['5550334', '0555550334']], ['declared national number', {'number': '555550334', 'type': 'national'}, ['0555550334', '0555550334']], ['unavailable presentation', {'number': '+42555550334', 'presentation': 'unavailable'}, ['Unavailable', None]], ['allowed but empty', {'number': '', 'presentation': 'allowed'}, ['Unknown', None]], ['punctuation only', {'number': '---'}, ['Unknown', None]], ['restricted without number', {'number': None, 'presentation': 'restricted'}, ['Private', None]]], [['own-country international number', {'number': '+42555550445', 'type': 'international'}, ['+42555550445', '0555550445']], ['unknown type with padded plus', {'number': ' +83 55504545'}, ['+8355504545', '008355504545']], ['unknown type with exit prefix', {'number': '0083 55504545'}, ['+8355504545', '008355504545']], ['unknown type with trunk', {'number': '0555550445'}, ['0555550445', '0555550445']], ['unknown type starting with the country digits', {'number': '425550445'}, ['425550445', '055425550445']], ['subscriber number', {'number': '5550445'}, ['5550445', '0555550445']], ['declared national number', {'number': '555550445', 'type': 'national'}, ['0555550445', '0555550445']], ['unavailable presentation', {'number': '+42555550445', 'presentation': 'unavailable'}, ['Unavailable', None]], ['allowed but empty', {'number': '', 'presentation': 'allowed'}, ['Unknown', None]], ['punctuation only', {'number': '---'}, ['Unknown', None]], ['restricted without number', {'number': None, 'presentation': 'restricted'}, ['Private', None]]], [['own-country international number', {'number': '+42555550556', 'type': 'international'}, ['+42555550556', '0555550556']], ['unknown type with padded plus', {'number': ' +83 55505656'}, ['+8355505656', '008355505656']], ['unknown type with exit prefix', {'number': '0083 55505656'}, ['+8355505656', '008355505656']], ['unknown type with trunk', {'number': '0555550556'}, ['0555550556', '0555550556']], ['unknown type starting with the country digits', {'number': '425550556'}, ['425550556', '055425550556']], ['subscriber number', {'number': '5550556'}, ['5550556', '0555550556']], ['declared national number', {'number': '555550556', 'type': 'national'}, ['0555550556', '0555550556']], ['unavailable presentation', {'number': '+42555550556', 'presentation': 'unavailable'}, ['Unavailable', None]], ['allowed but empty', {'number': '', 'presentation': 'allowed'}, ['Unknown', None]], ['punctuation only', {'number': '---'}, ['Unknown', None]], ['restricted without number', {'number': None, 'presentation': 'restricted'}, ['Private', None]]]]
for label, arg, expected in fixtures[N - 1]:
check(label, solve(arg), expected)
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 |
|---|---|---|---|
| own-country international number | ['+42555550112', '0555550112'] | ['+42555550112', '0555550112'] | Passed |
| unknown type with padded plus | ['+8355501212', '008355501212'] | ['+8355501212', '008355501212'] | Passed |
| unknown type with exit prefix | ['+8355501212', '008355501212'] | ['+8355501212', '008355501212'] | Passed |
| unknown type with trunk | ['0555550112', '0555550112'] | ['0555550112', '0555550112'] | Passed |
| unknown type starting with the country digits | ['425550112', '055425550112'] | ['425550112', '055425550112'] | Passed |
| subscriber number | ['5550112', '0555550112'] | ['5550112', '0555550112'] | Passed |
| declared national number | ['0555550112', '0555550112'] | ['0555550112', '0555550112'] | Passed |
| unavailable presentation | ['Unavailable', None] | ['Unavailable', None] | Passed |
| allowed but empty | ['Unknown', None] | ['Unknown', None] | Passed |
| punctuation only | ['Unknown', None] | ['Unknown', None] | Passed |
| restricted without number | ['Private', None] | ['Private', None] | Passed |
SHA-256 / b8761f606ccf5906e200671e8eb31893e3433102275211374e238d45d563f7f7
Verification & scope
A deterministic toy contract over synthetic, obviously fictitious telephone numbers and toy country tables. The rules are stipulated for this model only and make no claim of conformance with any numbering plan or telecommunications standard. 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 2026-09-29T14:52:26.275235+00:00.
Case digest / 983740001b79416992f84c39f7b293062a1406d7f31763e27954d7568ac2e42f