FA-73906 / Feature flag rollout bucketing / Open access

Flag targeting precedence: Matched rule index is reported one-based · case 01

Evaluation reasons point at the rule after the one that actually matched.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The reason reports index + 1 although the contract uses zero-based rule positions.

VERIFIED REPAIR

Report the zero-based enumerate index of the matching rule.

Unsuccessful approach: Counting only rules whose attribute is present renumbers rules after a skipped one.

Case contract

An off flag serves its off variation (reason OFF). Otherwise individual targets (checked by sorted variation name) win with reason TARGET, then rules in order, then the fallthrough. A rule matches only when the user has its attribute: op in = membership, startsWith = case-sensitive string prefix, lt = numeric less-than any value; negate inverts a present attribute result. Return [variation, reason, zero-based rule index or -1].

Why this case matters

Evaluation order decides whether QA allowlists, segment rules and defaults behave predictably.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(flag, user):
    if not flag.get('on'):
        return [flag.get('off'), 'OFF', -1]
    key = user.get('key')
    for variation in sorted(flag.get('targets', {})):
        if key in flag['targets'][variation]:
            return [variation, 'TARGET', -1]
    for index, rule in enumerate(flag.get('rules', [])):
        if rule['attr'] not in user:
            continue
        value = user[rule['attr']]
        if rule['op'] == 'in':
            hit = value in rule['values']
        elif rule['op'] == 'startsWith':
            hit = isinstance(value, str) and any(value.startswith(v) for v in rule['values'])
        else:
            hit = isinstance(value, (int, float)) and not isinstance(value, bool) and any(value < v for v in rule['values'])
        if rule.get('negate'):
            hit = not hit
        if hit:
            return [rule['variation'], 'RULE', index + 1]
    return [flag.get('fallthrough'), 'FALLTHROUGH', -1]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('individual target beats a matching rule',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {'v1': ['k1']},
     'rules': [{'attr': 'country', 'op': 'in', 'values': ['US'], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k1', 'country': 'US'}],
   ['v1', 'TARGET', -1]),
  ('negated rule does not match a missing attribute',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v3',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': True, 'variation': 'v2'}]},
    {'key': 'k2'}],
   ['v3', 'FALLTHROUGH', -1]),
  ('off flag serves off variation',
   [{'on': False, 'off': 'v1', 'fallthrough': 'v2', 'targets': {}, 'rules': []}, {'key': 'k1'}],
   ['v1', 'OFF', -1]),
  ('second rule reports index one',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'country', 'op': 'in', 'values': ['FR'], 'negate': False, 'variation': 'v1'},
               {'attr': 'country', 'op': 'in', 'values': ['DE'], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k3', 'country': 'DE'}],
   ['v2', 'RULE', 1]),
  ('prefix match is case sensitive',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email', 'op': 'startsWith', 'values': ['ann'], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k4', 'email': 'Ann@x.io'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('rule index skips rules on absent attributes',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': False, 'variation': 'v1'},
               {'attr': 'age', 'op': 'lt', 'values': [21], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k5', 'age': 19}],
   ['v2', 'RULE', 1]),
  ('targeting sample 1',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {'v1': []},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['a', 'Ann'],
                'negate': False,
                'variation': 'v2'},
               {'attr': 'age', 'op': 'lt', 'values': [21, 18], 'negate': False, 'variation': 'v0'},
               {'attr': 'age', 'op': 'lt', 'values': [18, 30], 'negate': True, 'variation': 'v2'},
               {'attr': 'email',
                'op': 'startsWith',
                'values': ['a', 'Ann'],
                'negate': False,
                'variation': 'v2'}]},
    {'key': 'k2', 'country': 'DE', 'age': 20, 'plan': 'team'}],
   ['v0', 'RULE', 1]),
  ('targeting sample 2',
   [{'on': True, 'off': 'v1', 'fallthrough': 'v0', 'targets': {'v2': []}, 'rules': []},
    {'key': 'k6', 'age': 40, 'plan': 'pro'}],
   ['v0', 'FALLTHROUGH', -1])],
 [('negated rule does not match a missing attribute',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v3',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': True, 'variation': 'v2'}]},
    {'key': 'k2'}],
   ['v3', 'FALLTHROUGH', -1]),
  ('off flag serves off variation',
   [{'on': False, 'off': 'v1', 'fallthrough': 'v2', 'targets': {}, 'rules': []}, {'key': 'k1'}],
   ['v1', 'OFF', -1]),
  ('second rule reports index one',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'country', 'op': 'in', 'values': ['FR'], 'negate': False, 'variation': 'v1'},
               {'attr': 'country', 'op': 'in', 'values': ['DE'], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k3', 'country': 'DE'}],
   ['v2', 'RULE', 1]),
  ('prefix match is case sensitive',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email', 'op': 'startsWith', 'values': ['ann'], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k4', 'email': 'Ann@x.io'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('rule index skips rules on absent attributes',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': False, 'variation': 'v1'},
               {'attr': 'age', 'op': 'lt', 'values': [21], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k5', 'age': 19}],
   ['v2', 'RULE', 1]),
  ('targeting sample 6',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v3',
     'targets': {},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [18, 65], 'negate': False, 'variation': 'v1'},
               {'attr': 'plan', 'op': 'in', 'values': ['DE', 'free'], 'negate': True, 'variation': 'v2'}]},
    {'key': 'k5', 'country': 'DE', 'plan': 'team'}],
   ['v2', 'RULE', 1]),
  ('targeting sample 7',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['FR', 'free'], 'negate': True, 'variation': 'v1'},
               {'attr': 'plan', 'op': 'in', 'values': ['FR', 'US'], 'negate': False, 'variation': 'v0'}]},
    {'key': 'k6', 'country': 'JP', 'email': 'annie', 'age': 17, 'plan': 'free'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('targeting sample 13',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v0',
     'targets': {'v1': ['k3'], 'v2': ['k4']},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['DE', 'free'], 'negate': True, 'variation': 'v2'}]},
    {'key': 'k5', 'country': 'US', 'email': 'qa-1@z.io', 'plan': 'team'}],
   ['v2', 'RULE', 0])],
 [('off flag serves off variation',
   [{'on': False, 'off': 'v1', 'fallthrough': 'v2', 'targets': {}, 'rules': []}, {'key': 'k1'}],
   ['v1', 'OFF', -1]),
  ('second rule reports index one',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'country', 'op': 'in', 'values': ['FR'], 'negate': False, 'variation': 'v1'},
               {'attr': 'country', 'op': 'in', 'values': ['DE'], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k3', 'country': 'DE'}],
   ['v2', 'RULE', 1]),
  ('prefix match is case sensitive',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email', 'op': 'startsWith', 'values': ['ann'], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k4', 'email': 'Ann@x.io'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('rule index skips rules on absent attributes',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': False, 'variation': 'v1'},
               {'attr': 'age', 'op': 'lt', 'values': [21], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k5', 'age': 19}],
   ['v2', 'RULE', 1]),
  ('target to fallthrough variation still reports TARGET',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v2',
     'targets': {'v2': ['k1']},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [30], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k1', 'age': 20}],
   ['v2', 'TARGET', -1]),
  ('targeting sample 11',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v3',
     'targets': {'v3': ['k2'], 'v2': ['k4', 'k2']},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['qa-', 'a'],
                'negate': False,
                'variation': 'v1'},
               {'attr': 'country', 'op': 'in', 'values': ['DE', 'FR'], 'negate': True, 'variation': 'v3'},
               {'attr': 'email',
                'op': 'startsWith',
                'values': ['qa-', 'a'],
                'negate': False,
                'variation': 'v1'}]},
    {'key': 'k6', 'email': 'annie', 'age': 40, 'plan': 'free'}],
   ['v1', 'RULE', 0]),
  ('targeting sample 23',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v2',
     'targets': {'v1': ['k5', 'k3'], 'v2': []},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['ann', 'qa-'],
                'negate': False,
                'variation': 'v2'},
               {'attr': 'plan', 'op': 'in', 'values': ['pro', 'DE'], 'negate': False, 'variation': 'v3'}]},
    {'key': 'k2', 'age': 17, 'plan': 'pro'}],
   ['v3', 'RULE', 1]),
  ('targeting sample 35',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {'v1': [], 'v3': ['k3', 'k4']},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['ann', 'qa-'],
                'negate': False,
                'variation': 'v2'},
               {'attr': 'age', 'op': 'lt', 'values': [65, 18], 'negate': True, 'variation': 'v2'}]},
    {'key': 'k1', 'email': 'Ann@x.io', 'age': 70}],
   ['v2', 'RULE', 1])],
 [('second rule reports index one',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'country', 'op': 'in', 'values': ['FR'], 'negate': False, 'variation': 'v1'},
               {'attr': 'country', 'op': 'in', 'values': ['DE'], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k3', 'country': 'DE'}],
   ['v2', 'RULE', 1]),
  ('prefix match is case sensitive',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email', 'op': 'startsWith', 'values': ['ann'], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k4', 'email': 'Ann@x.io'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('rule index skips rules on absent attributes',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': False, 'variation': 'v1'},
               {'attr': 'age', 'op': 'lt', 'values': [21], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k5', 'age': 19}],
   ['v2', 'RULE', 1]),
  ('target to fallthrough variation still reports TARGET',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v2',
     'targets': {'v2': ['k1']},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [30], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k1', 'age': 20}],
   ['v2', 'TARGET', -1]),
  ('no rule matches uses fallthrough',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v3',
     'targets': {'v1': ['k9']},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [18], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k1', 'age': 40}],
   ['v3', 'FALLTHROUGH', -1]),
  ('targeting sample 1',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {'v1': []},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['a', 'Ann'],
                'negate': False,
                'variation': 'v2'},
               {'attr': 'age', 'op': 'lt', 'values': [21, 18], 'negate': False, 'variation': 'v0'},
               {'attr': 'age', 'op': 'lt', 'values': [18, 30], 'negate': True, 'variation': 'v2'},
               {'attr': 'email',
                'op': 'startsWith',
                'values': ['a', 'Ann'],
                'negate': False,
                'variation': 'v2'}]},
    {'key': 'k2', 'country': 'DE', 'age': 20, 'plan': 'team'}],
   ['v0', 'RULE', 1]),
  ('targeting sample 16',
   [{'on': True, 'off': 'v0', 'fallthrough': 'v2', 'targets': {}, 'rules': []},
    {'key': 'k5', 'age': 40, 'plan': 'free'}],
   ['v2', 'FALLTHROUGH', -1]),
  ('targeting sample 17',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v3',
     'targets': {},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['ann', 'a'],
                'negate': True,
                'variation': 'v0'},
               {'attr': 'plan', 'op': 'lt', 'values': [30, 18], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k6', 'country': 'JP', 'email': 'ann@x.io', 'plan': 'team'}],
   ['v3', 'FALLTHROUGH', -1])],
 [('prefix match is case sensitive',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email', 'op': 'startsWith', 'values': ['ann'], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k4', 'email': 'Ann@x.io'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('rule index skips rules on absent attributes',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': False, 'variation': 'v1'},
               {'attr': 'age', 'op': 'lt', 'values': [21], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k5', 'age': 19}],
   ['v2', 'RULE', 1]),
  ('target to fallthrough variation still reports TARGET',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v2',
     'targets': {'v2': ['k1']},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [30], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k1', 'age': 20}],
   ['v2', 'TARGET', -1]),
  ('no rule matches uses fallthrough',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v3',
     'targets': {'v1': ['k9']},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [18], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k1', 'age': 40}],
   ['v3', 'FALLTHROUGH', -1]),
  ('prefix operand order matters',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['annie@corp'],
                'negate': False,
                'variation': 'v1'}]},
    {'key': 'k2', 'email': 'annie'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('targeting sample 14',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan',
                'op': 'startsWith',
                'values': ['bob', 'ann'],
                'negate': False,
                'variation': 'v3'},
               {'attr': 'email',
                'op': 'startsWith',
                'values': ['bob', 'a'],
                'negate': True,
                'variation': 'v2'},
               {'attr': 'email',
                'op': 'startsWith',
                'values': ['bob', 'a'],
                'negate': False,
                'variation': 'v3'}]},
    {'key': 'k5', 'email': 'qa-1@z.io'}],
   ['v2', 'RULE', 1]),
  ('targeting sample 21',
   [{'on': True, 'off': 'v1', 'fallthrough': 'v2', 'targets': {}, 'rules': []},
    {'key': 'k3', 'email': 'qa-1@z.io', 'plan': 'free'}],
   ['v2', 'FALLTHROUGH', -1]),
  ('targeting sample 22',
   [{'on': False, 'off': 'v0', 'fallthrough': 'v2', 'targets': {'v1': [], 'v3': ['k3']}, 'rules': []},
    {'key': 'k6', 'country': 'DE', 'email': 'Ann@x.io', 'plan': 'team'}],
   ['v0', 'OFF', -1])]]
for label, args, expected in fixtures[N - 1]:
    check(label, solve(*args), 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
individual target beats a matching rule	`['v1', 'TARGET', -1]`	`['v1', 'TARGET', -1]`	Passed
negated rule does not match a missing attribute	`['v3', 'FALLTHROUGH', -1]`	`['v3', 'FALLTHROUGH', -1]`	Passed
off flag serves off variation	`['v1', 'OFF', -1]`	`['v1', 'OFF', -1]`	Passed
second rule reports index one	`['v2', 'RULE', 2]`	`['v2', 'RULE', 1]`	Failed
prefix match is case sensitive	`['v0', 'FALLTHROUGH', -1]`	`['v0', 'FALLTHROUGH', -1]`	Passed
rule index skips rules on absent attributes	`['v2', 'RULE', 2]`	`['v2', 'RULE', 1]`	Failed
targeting sample 1	`['v0', 'RULE', 2]`	`['v0', 'RULE', 1]`	Failed
targeting sample 2	`['v0', 'FALLTHROUGH', -1]`	`['v0', 'FALLTHROUGH', -1]`	Passed

SHA-256 / 0e1ec2543579903018896064554553bc60687fadb68a5b1ec35fc44392af2829

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(flag, user):
    if not flag.get('on'):
        return [flag.get('off'), 'OFF', -1]
    key = user.get('key')
    for variation in sorted(flag.get('targets', {})):
        if key in flag['targets'][variation]:
            return [variation, 'TARGET', -1]
    seen = -1
    for index, rule in enumerate(flag.get('rules', [])):
        if rule['attr'] not in user:
            continue
        seen += 1
        value = user[rule['attr']]
        if rule['op'] == 'in':
            hit = value in rule['values']
        elif rule['op'] == 'startsWith':
            hit = isinstance(value, str) and any(value.startswith(v) for v in rule['values'])
        else:
            hit = isinstance(value, (int, float)) and not isinstance(value, bool) and any(value < v for v in rule['values'])
        if rule.get('negate'):
            hit = not hit
        if hit:
            return [rule['variation'], 'RULE', seen]
    return [flag.get('fallthrough'), 'FALLTHROUGH', -1]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('individual target beats a matching rule',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {'v1': ['k1']},
     'rules': [{'attr': 'country', 'op': 'in', 'values': ['US'], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k1', 'country': 'US'}],
   ['v1', 'TARGET', -1]),
  ('negated rule does not match a missing attribute',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v3',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': True, 'variation': 'v2'}]},
    {'key': 'k2'}],
   ['v3', 'FALLTHROUGH', -1]),
  ('off flag serves off variation',
   [{'on': False, 'off': 'v1', 'fallthrough': 'v2', 'targets': {}, 'rules': []}, {'key': 'k1'}],
   ['v1', 'OFF', -1]),
  ('second rule reports index one',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'country', 'op': 'in', 'values': ['FR'], 'negate': False, 'variation': 'v1'},
               {'attr': 'country', 'op': 'in', 'values': ['DE'], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k3', 'country': 'DE'}],
   ['v2', 'RULE', 1]),
  ('prefix match is case sensitive',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email', 'op': 'startsWith', 'values': ['ann'], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k4', 'email': 'Ann@x.io'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('rule index skips rules on absent attributes',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': False, 'variation': 'v1'},
               {'attr': 'age', 'op': 'lt', 'values': [21], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k5', 'age': 19}],
   ['v2', 'RULE', 1]),
  ('targeting sample 1',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {'v1': []},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['a', 'Ann'],
                'negate': False,
                'variation': 'v2'},
               {'attr': 'age', 'op': 'lt', 'values': [21, 18], 'negate': False, 'variation': 'v0'},
               {'attr': 'age', 'op': 'lt', 'values': [18, 30], 'negate': True, 'variation': 'v2'},
               {'attr': 'email',
                'op': 'startsWith',
                'values': ['a', 'Ann'],
                'negate': False,
                'variation': 'v2'}]},
    {'key': 'k2', 'country': 'DE', 'age': 20, 'plan': 'team'}],
   ['v0', 'RULE', 1]),
  ('targeting sample 2',
   [{'on': True, 'off': 'v1', 'fallthrough': 'v0', 'targets': {'v2': []}, 'rules': []},
    {'key': 'k6', 'age': 40, 'plan': 'pro'}],
   ['v0', 'FALLTHROUGH', -1])],
 [('negated rule does not match a missing attribute',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v3',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': True, 'variation': 'v2'}]},
    {'key': 'k2'}],
   ['v3', 'FALLTHROUGH', -1]),
  ('off flag serves off variation',
   [{'on': False, 'off': 'v1', 'fallthrough': 'v2', 'targets': {}, 'rules': []}, {'key': 'k1'}],
   ['v1', 'OFF', -1]),
  ('second rule reports index one',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'country', 'op': 'in', 'values': ['FR'], 'negate': False, 'variation': 'v1'},
               {'attr': 'country', 'op': 'in', 'values': ['DE'], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k3', 'country': 'DE'}],
   ['v2', 'RULE', 1]),
  ('prefix match is case sensitive',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email', 'op': 'startsWith', 'values': ['ann'], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k4', 'email': 'Ann@x.io'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('rule index skips rules on absent attributes',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': False, 'variation': 'v1'},
               {'attr': 'age', 'op': 'lt', 'values': [21], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k5', 'age': 19}],
   ['v2', 'RULE', 1]),
  ('targeting sample 6',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v3',
     'targets': {},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [18, 65], 'negate': False, 'variation': 'v1'},
               {'attr': 'plan', 'op': 'in', 'values': ['DE', 'free'], 'negate': True, 'variation': 'v2'}]},
    {'key': 'k5', 'country': 'DE', 'plan': 'team'}],
   ['v2', 'RULE', 1]),
  ('targeting sample 7',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['FR', 'free'], 'negate': True, 'variation': 'v1'},
               {'attr': 'plan', 'op': 'in', 'values': ['FR', 'US'], 'negate': False, 'variation': 'v0'}]},
    {'key': 'k6', 'country': 'JP', 'email': 'annie', 'age': 17, 'plan': 'free'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('targeting sample 13',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v0',
     'targets': {'v1': ['k3'], 'v2': ['k4']},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['DE', 'free'], 'negate': True, 'variation': 'v2'}]},
    {'key': 'k5', 'country': 'US', 'email': 'qa-1@z.io', 'plan': 'team'}],
   ['v2', 'RULE', 0])],
 [('off flag serves off variation',
   [{'on': False, 'off': 'v1', 'fallthrough': 'v2', 'targets': {}, 'rules': []}, {'key': 'k1'}],
   ['v1', 'OFF', -1]),
  ('second rule reports index one',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'country', 'op': 'in', 'values': ['FR'], 'negate': False, 'variation': 'v1'},
               {'attr': 'country', 'op': 'in', 'values': ['DE'], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k3', 'country': 'DE'}],
   ['v2', 'RULE', 1]),
  ('prefix match is case sensitive',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email', 'op': 'startsWith', 'values': ['ann'], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k4', 'email': 'Ann@x.io'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('rule index skips rules on absent attributes',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': False, 'variation': 'v1'},
               {'attr': 'age', 'op': 'lt', 'values': [21], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k5', 'age': 19}],
   ['v2', 'RULE', 1]),
  ('target to fallthrough variation still reports TARGET',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v2',
     'targets': {'v2': ['k1']},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [30], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k1', 'age': 20}],
   ['v2', 'TARGET', -1]),
  ('targeting sample 11',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v3',
     'targets': {'v3': ['k2'], 'v2': ['k4', 'k2']},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['qa-', 'a'],
                'negate': False,
                'variation': 'v1'},
               {'attr': 'country', 'op': 'in', 'values': ['DE', 'FR'], 'negate': True, 'variation': 'v3'},
               {'attr': 'email',
                'op': 'startsWith',
                'values': ['qa-', 'a'],
                'negate': False,
                'variation': 'v1'}]},
    {'key': 'k6', 'email': 'annie', 'age': 40, 'plan': 'free'}],
   ['v1', 'RULE', 0]),
  ('targeting sample 23',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v2',
     'targets': {'v1': ['k5', 'k3'], 'v2': []},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['ann', 'qa-'],
                'negate': False,
                'variation': 'v2'},
               {'attr': 'plan', 'op': 'in', 'values': ['pro', 'DE'], 'negate': False, 'variation': 'v3'}]},
    {'key': 'k2', 'age': 17, 'plan': 'pro'}],
   ['v3', 'RULE', 1]),
  ('targeting sample 35',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {'v1': [], 'v3': ['k3', 'k4']},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['ann', 'qa-'],
                'negate': False,
                'variation': 'v2'},
               {'attr': 'age', 'op': 'lt', 'values': [65, 18], 'negate': True, 'variation': 'v2'}]},
    {'key': 'k1', 'email': 'Ann@x.io', 'age': 70}],
   ['v2', 'RULE', 1])],
 [('second rule reports index one',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'country', 'op': 'in', 'values': ['FR'], 'negate': False, 'variation': 'v1'},
               {'attr': 'country', 'op': 'in', 'values': ['DE'], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k3', 'country': 'DE'}],
   ['v2', 'RULE', 1]),
  ('prefix match is case sensitive',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email', 'op': 'startsWith', 'values': ['ann'], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k4', 'email': 'Ann@x.io'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('rule index skips rules on absent attributes',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': False, 'variation': 'v1'},
               {'attr': 'age', 'op': 'lt', 'values': [21], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k5', 'age': 19}],
   ['v2', 'RULE', 1]),
  ('target to fallthrough variation still reports TARGET',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v2',
     'targets': {'v2': ['k1']},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [30], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k1', 'age': 20}],
   ['v2', 'TARGET', -1]),
  ('no rule matches uses fallthrough',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v3',
     'targets': {'v1': ['k9']},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [18], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k1', 'age': 40}],
   ['v3', 'FALLTHROUGH', -1]),
  ('targeting sample 1',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {'v1': []},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['a', 'Ann'],
                'negate': False,
                'variation': 'v2'},
               {'attr': 'age', 'op': 'lt', 'values': [21, 18], 'negate': False, 'variation': 'v0'},
               {'attr': 'age', 'op': 'lt', 'values': [18, 30], 'negate': True, 'variation': 'v2'},
               {'attr': 'email',
                'op': 'startsWith',
                'values': ['a', 'Ann'],
                'negate': False,
                'variation': 'v2'}]},
    {'key': 'k2', 'country': 'DE', 'age': 20, 'plan': 'team'}],
   ['v0', 'RULE', 1]),
  ('targeting sample 16',
   [{'on': True, 'off': 'v0', 'fallthrough': 'v2', 'targets': {}, 'rules': []},
    {'key': 'k5', 'age': 40, 'plan': 'free'}],
   ['v2', 'FALLTHROUGH', -1]),
  ('targeting sample 17',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v3',
     'targets': {},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['ann', 'a'],
                'negate': True,
                'variation': 'v0'},
               {'attr': 'plan', 'op': 'lt', 'values': [30, 18], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k6', 'country': 'JP', 'email': 'ann@x.io', 'plan': 'team'}],
   ['v3', 'FALLTHROUGH', -1])],
 [('prefix match is case sensitive',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email', 'op': 'startsWith', 'values': ['ann'], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k4', 'email': 'Ann@x.io'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('rule index skips rules on absent attributes',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': False, 'variation': 'v1'},
               {'attr': 'age', 'op': 'lt', 'values': [21], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k5', 'age': 19}],
   ['v2', 'RULE', 1]),
  ('target to fallthrough variation still reports TARGET',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v2',
     'targets': {'v2': ['k1']},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [30], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k1', 'age': 20}],
   ['v2', 'TARGET', -1]),
  ('no rule matches uses fallthrough',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v3',
     'targets': {'v1': ['k9']},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [18], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k1', 'age': 40}],
   ['v3', 'FALLTHROUGH', -1]),
  ('prefix operand order matters',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['annie@corp'],
                'negate': False,
                'variation': 'v1'}]},
    {'key': 'k2', 'email': 'annie'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('targeting sample 14',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan',
                'op': 'startsWith',
                'values': ['bob', 'ann'],
                'negate': False,
                'variation': 'v3'},
               {'attr': 'email',
                'op': 'startsWith',
                'values': ['bob', 'a'],
                'negate': True,
                'variation': 'v2'},
               {'attr': 'email',
                'op': 'startsWith',
                'values': ['bob', 'a'],
                'negate': False,
                'variation': 'v3'}]},
    {'key': 'k5', 'email': 'qa-1@z.io'}],
   ['v2', 'RULE', 1]),
  ('targeting sample 21',
   [{'on': True, 'off': 'v1', 'fallthrough': 'v2', 'targets': {}, 'rules': []},
    {'key': 'k3', 'email': 'qa-1@z.io', 'plan': 'free'}],
   ['v2', 'FALLTHROUGH', -1]),
  ('targeting sample 22',
   [{'on': False, 'off': 'v0', 'fallthrough': 'v2', 'targets': {'v1': [], 'v3': ['k3']}, 'rules': []},
    {'key': 'k6', 'country': 'DE', 'email': 'Ann@x.io', 'plan': 'team'}],
   ['v0', 'OFF', -1])]]
for label, args, expected in fixtures[N - 1]:
    check(label, solve(*args), 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
individual target beats a matching rule	`['v1', 'TARGET', -1]`	`['v1', 'TARGET', -1]`	Passed
negated rule does not match a missing attribute	`['v3', 'FALLTHROUGH', -1]`	`['v3', 'FALLTHROUGH', -1]`	Passed
off flag serves off variation	`['v1', 'OFF', -1]`	`['v1', 'OFF', -1]`	Passed
second rule reports index one	`['v2', 'RULE', 1]`	`['v2', 'RULE', 1]`	Passed
prefix match is case sensitive	`['v0', 'FALLTHROUGH', -1]`	`['v0', 'FALLTHROUGH', -1]`	Passed
rule index skips rules on absent attributes	`['v2', 'RULE', 0]`	`['v2', 'RULE', 1]`	Failed
targeting sample 1	`['v0', 'RULE', 0]`	`['v0', 'RULE', 1]`	Failed
targeting sample 2	`['v0', 'FALLTHROUGH', -1]`	`['v0', 'FALLTHROUGH', -1]`	Passed

SHA-256 / a323e88e79e77bd7e51969738de22ba04cdf1f79da207a257edddc33694e5caf

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(flag, user):
    if not flag.get('on'):
        return [flag.get('off'), 'OFF', -1]
    key = user.get('key')
    for variation in sorted(flag.get('targets', {})):
        if key in flag['targets'][variation]:
            return [variation, 'TARGET', -1]
    for index, rule in enumerate(flag.get('rules', [])):
        if rule['attr'] not in user:
            continue
        value = user[rule['attr']]
        if rule['op'] == 'in':
            hit = value in rule['values']
        elif rule['op'] == 'startsWith':
            hit = isinstance(value, str) and any(value.startswith(v) for v in rule['values'])
        else:
            hit = isinstance(value, (int, float)) and not isinstance(value, bool) and any(value < v for v in rule['values'])
        if rule.get('negate'):
            hit = not hit
        if hit:
            return [rule['variation'], 'RULE', index]
    return [flag.get('fallthrough'), 'FALLTHROUGH', -1]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('individual target beats a matching rule',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {'v1': ['k1']},
     'rules': [{'attr': 'country', 'op': 'in', 'values': ['US'], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k1', 'country': 'US'}],
   ['v1', 'TARGET', -1]),
  ('negated rule does not match a missing attribute',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v3',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': True, 'variation': 'v2'}]},
    {'key': 'k2'}],
   ['v3', 'FALLTHROUGH', -1]),
  ('off flag serves off variation',
   [{'on': False, 'off': 'v1', 'fallthrough': 'v2', 'targets': {}, 'rules': []}, {'key': 'k1'}],
   ['v1', 'OFF', -1]),
  ('second rule reports index one',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'country', 'op': 'in', 'values': ['FR'], 'negate': False, 'variation': 'v1'},
               {'attr': 'country', 'op': 'in', 'values': ['DE'], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k3', 'country': 'DE'}],
   ['v2', 'RULE', 1]),
  ('prefix match is case sensitive',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email', 'op': 'startsWith', 'values': ['ann'], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k4', 'email': 'Ann@x.io'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('rule index skips rules on absent attributes',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': False, 'variation': 'v1'},
               {'attr': 'age', 'op': 'lt', 'values': [21], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k5', 'age': 19}],
   ['v2', 'RULE', 1]),
  ('targeting sample 1',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {'v1': []},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['a', 'Ann'],
                'negate': False,
                'variation': 'v2'},
               {'attr': 'age', 'op': 'lt', 'values': [21, 18], 'negate': False, 'variation': 'v0'},
               {'attr': 'age', 'op': 'lt', 'values': [18, 30], 'negate': True, 'variation': 'v2'},
               {'attr': 'email',
                'op': 'startsWith',
                'values': ['a', 'Ann'],
                'negate': False,
                'variation': 'v2'}]},
    {'key': 'k2', 'country': 'DE', 'age': 20, 'plan': 'team'}],
   ['v0', 'RULE', 1]),
  ('targeting sample 2',
   [{'on': True, 'off': 'v1', 'fallthrough': 'v0', 'targets': {'v2': []}, 'rules': []},
    {'key': 'k6', 'age': 40, 'plan': 'pro'}],
   ['v0', 'FALLTHROUGH', -1])],
 [('negated rule does not match a missing attribute',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v3',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': True, 'variation': 'v2'}]},
    {'key': 'k2'}],
   ['v3', 'FALLTHROUGH', -1]),
  ('off flag serves off variation',
   [{'on': False, 'off': 'v1', 'fallthrough': 'v2', 'targets': {}, 'rules': []}, {'key': 'k1'}],
   ['v1', 'OFF', -1]),
  ('second rule reports index one',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'country', 'op': 'in', 'values': ['FR'], 'negate': False, 'variation': 'v1'},
               {'attr': 'country', 'op': 'in', 'values': ['DE'], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k3', 'country': 'DE'}],
   ['v2', 'RULE', 1]),
  ('prefix match is case sensitive',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email', 'op': 'startsWith', 'values': ['ann'], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k4', 'email': 'Ann@x.io'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('rule index skips rules on absent attributes',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': False, 'variation': 'v1'},
               {'attr': 'age', 'op': 'lt', 'values': [21], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k5', 'age': 19}],
   ['v2', 'RULE', 1]),
  ('targeting sample 6',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v3',
     'targets': {},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [18, 65], 'negate': False, 'variation': 'v1'},
               {'attr': 'plan', 'op': 'in', 'values': ['DE', 'free'], 'negate': True, 'variation': 'v2'}]},
    {'key': 'k5', 'country': 'DE', 'plan': 'team'}],
   ['v2', 'RULE', 1]),
  ('targeting sample 7',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['FR', 'free'], 'negate': True, 'variation': 'v1'},
               {'attr': 'plan', 'op': 'in', 'values': ['FR', 'US'], 'negate': False, 'variation': 'v0'}]},
    {'key': 'k6', 'country': 'JP', 'email': 'annie', 'age': 17, 'plan': 'free'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('targeting sample 13',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v0',
     'targets': {'v1': ['k3'], 'v2': ['k4']},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['DE', 'free'], 'negate': True, 'variation': 'v2'}]},
    {'key': 'k5', 'country': 'US', 'email': 'qa-1@z.io', 'plan': 'team'}],
   ['v2', 'RULE', 0])],
 [('off flag serves off variation',
   [{'on': False, 'off': 'v1', 'fallthrough': 'v2', 'targets': {}, 'rules': []}, {'key': 'k1'}],
   ['v1', 'OFF', -1]),
  ('second rule reports index one',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'country', 'op': 'in', 'values': ['FR'], 'negate': False, 'variation': 'v1'},
               {'attr': 'country', 'op': 'in', 'values': ['DE'], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k3', 'country': 'DE'}],
   ['v2', 'RULE', 1]),
  ('prefix match is case sensitive',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email', 'op': 'startsWith', 'values': ['ann'], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k4', 'email': 'Ann@x.io'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('rule index skips rules on absent attributes',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': False, 'variation': 'v1'},
               {'attr': 'age', 'op': 'lt', 'values': [21], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k5', 'age': 19}],
   ['v2', 'RULE', 1]),
  ('target to fallthrough variation still reports TARGET',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v2',
     'targets': {'v2': ['k1']},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [30], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k1', 'age': 20}],
   ['v2', 'TARGET', -1]),
  ('targeting sample 11',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v3',
     'targets': {'v3': ['k2'], 'v2': ['k4', 'k2']},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['qa-', 'a'],
                'negate': False,
                'variation': 'v1'},
               {'attr': 'country', 'op': 'in', 'values': ['DE', 'FR'], 'negate': True, 'variation': 'v3'},
               {'attr': 'email',
                'op': 'startsWith',
                'values': ['qa-', 'a'],
                'negate': False,
                'variation': 'v1'}]},
    {'key': 'k6', 'email': 'annie', 'age': 40, 'plan': 'free'}],
   ['v1', 'RULE', 0]),
  ('targeting sample 23',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v2',
     'targets': {'v1': ['k5', 'k3'], 'v2': []},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['ann', 'qa-'],
                'negate': False,
                'variation': 'v2'},
               {'attr': 'plan', 'op': 'in', 'values': ['pro', 'DE'], 'negate': False, 'variation': 'v3'}]},
    {'key': 'k2', 'age': 17, 'plan': 'pro'}],
   ['v3', 'RULE', 1]),
  ('targeting sample 35',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {'v1': [], 'v3': ['k3', 'k4']},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['ann', 'qa-'],
                'negate': False,
                'variation': 'v2'},
               {'attr': 'age', 'op': 'lt', 'values': [65, 18], 'negate': True, 'variation': 'v2'}]},
    {'key': 'k1', 'email': 'Ann@x.io', 'age': 70}],
   ['v2', 'RULE', 1])],
 [('second rule reports index one',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'country', 'op': 'in', 'values': ['FR'], 'negate': False, 'variation': 'v1'},
               {'attr': 'country', 'op': 'in', 'values': ['DE'], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k3', 'country': 'DE'}],
   ['v2', 'RULE', 1]),
  ('prefix match is case sensitive',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email', 'op': 'startsWith', 'values': ['ann'], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k4', 'email': 'Ann@x.io'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('rule index skips rules on absent attributes',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': False, 'variation': 'v1'},
               {'attr': 'age', 'op': 'lt', 'values': [21], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k5', 'age': 19}],
   ['v2', 'RULE', 1]),
  ('target to fallthrough variation still reports TARGET',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v2',
     'targets': {'v2': ['k1']},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [30], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k1', 'age': 20}],
   ['v2', 'TARGET', -1]),
  ('no rule matches uses fallthrough',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v3',
     'targets': {'v1': ['k9']},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [18], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k1', 'age': 40}],
   ['v3', 'FALLTHROUGH', -1]),
  ('targeting sample 1',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {'v1': []},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['a', 'Ann'],
                'negate': False,
                'variation': 'v2'},
               {'attr': 'age', 'op': 'lt', 'values': [21, 18], 'negate': False, 'variation': 'v0'},
               {'attr': 'age', 'op': 'lt', 'values': [18, 30], 'negate': True, 'variation': 'v2'},
               {'attr': 'email',
                'op': 'startsWith',
                'values': ['a', 'Ann'],
                'negate': False,
                'variation': 'v2'}]},
    {'key': 'k2', 'country': 'DE', 'age': 20, 'plan': 'team'}],
   ['v0', 'RULE', 1]),
  ('targeting sample 16',
   [{'on': True, 'off': 'v0', 'fallthrough': 'v2', 'targets': {}, 'rules': []},
    {'key': 'k5', 'age': 40, 'plan': 'free'}],
   ['v2', 'FALLTHROUGH', -1]),
  ('targeting sample 17',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v3',
     'targets': {},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['ann', 'a'],
                'negate': True,
                'variation': 'v0'},
               {'attr': 'plan', 'op': 'lt', 'values': [30, 18], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k6', 'country': 'JP', 'email': 'ann@x.io', 'plan': 'team'}],
   ['v3', 'FALLTHROUGH', -1])],
 [('prefix match is case sensitive',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email', 'op': 'startsWith', 'values': ['ann'], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k4', 'email': 'Ann@x.io'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('rule index skips rules on absent attributes',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan', 'op': 'in', 'values': ['pro'], 'negate': False, 'variation': 'v1'},
               {'attr': 'age', 'op': 'lt', 'values': [21], 'negate': False, 'variation': 'v2'}]},
    {'key': 'k5', 'age': 19}],
   ['v2', 'RULE', 1]),
  ('target to fallthrough variation still reports TARGET',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v2',
     'targets': {'v2': ['k1']},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [30], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k1', 'age': 20}],
   ['v2', 'TARGET', -1]),
  ('no rule matches uses fallthrough',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v3',
     'targets': {'v1': ['k9']},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [18], 'negate': False, 'variation': 'v1'}]},
    {'key': 'k1', 'age': 40}],
   ['v3', 'FALLTHROUGH', -1]),
  ('prefix operand order matters',
   [{'on': True,
     'off': 'v0',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'email',
                'op': 'startsWith',
                'values': ['annie@corp'],
                'negate': False,
                'variation': 'v1'}]},
    {'key': 'k2', 'email': 'annie'}],
   ['v0', 'FALLTHROUGH', -1]),
  ('targeting sample 14',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v0',
     'targets': {},
     'rules': [{'attr': 'plan',
                'op': 'startsWith',
                'values': ['bob', 'ann'],
                'negate': False,
                'variation': 'v3'},
               {'attr': 'email',
                'op': 'startsWith',
                'values': ['bob', 'a'],
                'negate': True,
                'variation': 'v2'},
               {'attr': 'email',
                'op': 'startsWith',
                'values': ['bob', 'a'],
                'negate': False,
                'variation': 'v3'}]},
    {'key': 'k5', 'email': 'qa-1@z.io'}],
   ['v2', 'RULE', 1]),
  ('targeting sample 21',
   [{'on': True, 'off': 'v1', 'fallthrough': 'v2', 'targets': {}, 'rules': []},
    {'key': 'k3', 'email': 'qa-1@z.io', 'plan': 'free'}],
   ['v2', 'FALLTHROUGH', -1]),
  ('targeting sample 22',
   [{'on': False, 'off': 'v0', 'fallthrough': 'v2', 'targets': {'v1': [], 'v3': ['k3']}, 'rules': []},
    {'key': 'k6', 'country': 'DE', 'email': 'Ann@x.io', 'plan': 'team'}],
   ['v0', 'OFF', -1])]]
for label, args, expected in fixtures[N - 1]:
    check(label, solve(*args), 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
individual target beats a matching rule	`['v1', 'TARGET', -1]`	`['v1', 'TARGET', -1]`	Passed
negated rule does not match a missing attribute	`['v3', 'FALLTHROUGH', -1]`	`['v3', 'FALLTHROUGH', -1]`	Passed
off flag serves off variation	`['v1', 'OFF', -1]`	`['v1', 'OFF', -1]`	Passed
second rule reports index one	`['v2', 'RULE', 1]`	`['v2', 'RULE', 1]`	Passed
prefix match is case sensitive	`['v0', 'FALLTHROUGH', -1]`	`['v0', 'FALLTHROUGH', -1]`	Passed
rule index skips rules on absent attributes	`['v2', 'RULE', 1]`	`['v2', 'RULE', 1]`	Passed
targeting sample 1	`['v0', 'RULE', 1]`	`['v0', 'RULE', 1]`	Passed
targeting sample 2	`['v0', 'FALLTHROUGH', -1]`	`['v0', 'FALLTHROUGH', -1]`	Passed

SHA-256 / 022c664cbd29db6a049b71689d57e874976d3778c1e7fa08be79fd690569fdfd

Verification & scope

A deterministic toy flag-evaluation model with a stipulated contract; it does not reproduce any vendor SDK byte for byte. 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 2026-09-29T14:48:51.876723+00:00.

Case digest / a03590c58fd2bd14698bccd9ff4b4dea2119a1f4507939d52ec2bea95da79d11