FA-73891 / Feature flag rollout bucketing / Open access

Flag targeting precedence: Rules are evaluated before individual targets · case 01

A QA engineer added to an individual target list still receives the variation of a broad rule.

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

ROOT CAUSE

The individual-target loop runs after the rule loop, so the first matching rule returns first.

VERIFIED REPAIR

Check individual targets immediately after the on/off check and before any rule.

Unsuccessful approach: Skipping targets that point at the fallthrough variation lets a rule override those targeted users.

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 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]
    for variation in sorted(flag.get('targets', {})):
        if key in flag['targets'][variation]:
            return [variation, 'TARGET', -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]),
  ('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 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]),
  ('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 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])],
 [('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]),
  ('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 12',
   [{'on': True, 'off': 'v1', 'fallthrough': 'v0', 'targets': {'v1': ['k1', 'k4'], 'v2': []}, 'rules': []},
    {'key': 'k1', 'age': 30, 'plan': 'free'}],
   ['v1', 'TARGET', -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 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]),
  ('targeting sample 18',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v3',
     'targets': {'v2': []},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [21, 18], 'negate': False, 'variation': 'v0'},
               {'attr': 'plan', 'op': 'in', 'values': ['FR', 'DE'], 'negate': False, 'variation': 'v3'},
               {'attr': 'age', 'op': 'lt', 'values': [21, 18], 'negate': False, 'variation': 'v0'}]},
    {'key': 'k1', 'country': 'JP', 'age': 20, 'plan': 'free'}],
   ['v0', 'RULE', 0])],
 [('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]),
  ('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 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	`['v2', 'RULE', 0]`	`['v1', 'TARGET', -1]`	Failed
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
target to fallthrough variation still reports TARGET	`['v1', 'RULE', 0]`	`['v2', 'TARGET', -1]`	Failed
targeting sample 1	`['v0', 'RULE', 1]`	`['v0', 'RULE', 1]`	Passed
targeting sample 2	`['v0', 'FALLTHROUGH', -1]`	`['v0', 'FALLTHROUGH', -1]`	Passed

SHA-256 / d8067e4962f59a57abc4c22b33298dd3ada342cb62d6a371c57b9cfc86513911

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] and variation != flag.get('fallthrough'):
            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]),
  ('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 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]),
  ('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 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])],
 [('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]),
  ('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 12',
   [{'on': True, 'off': 'v1', 'fallthrough': 'v0', 'targets': {'v1': ['k1', 'k4'], 'v2': []}, 'rules': []},
    {'key': 'k1', 'age': 30, 'plan': 'free'}],
   ['v1', 'TARGET', -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 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]),
  ('targeting sample 18',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v3',
     'targets': {'v2': []},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [21, 18], 'negate': False, 'variation': 'v0'},
               {'attr': 'plan', 'op': 'in', 'values': ['FR', 'DE'], 'negate': False, 'variation': 'v3'},
               {'attr': 'age', 'op': 'lt', 'values': [21, 18], 'negate': False, 'variation': 'v0'}]},
    {'key': 'k1', 'country': 'JP', 'age': 20, 'plan': 'free'}],
   ['v0', 'RULE', 0])],
 [('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]),
  ('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 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
target to fallthrough variation still reports TARGET	`['v1', 'RULE', 0]`	`['v2', 'TARGET', -1]`	Failed
targeting sample 1	`['v0', 'RULE', 1]`	`['v0', 'RULE', 1]`	Passed
targeting sample 2	`['v0', 'FALLTHROUGH', -1]`	`['v0', 'FALLTHROUGH', -1]`	Passed

SHA-256 / 7d9e8b470748ffe881f5f5418f955d1cf72e72758154c3624becf7db48903643

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]),
  ('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 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]),
  ('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 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])],
 [('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]),
  ('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 12',
   [{'on': True, 'off': 'v1', 'fallthrough': 'v0', 'targets': {'v1': ['k1', 'k4'], 'v2': []}, 'rules': []},
    {'key': 'k1', 'age': 30, 'plan': 'free'}],
   ['v1', 'TARGET', -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 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]),
  ('targeting sample 18',
   [{'on': True,
     'off': 'v1',
     'fallthrough': 'v3',
     'targets': {'v2': []},
     'rules': [{'attr': 'age', 'op': 'lt', 'values': [21, 18], 'negate': False, 'variation': 'v0'},
               {'attr': 'plan', 'op': 'in', 'values': ['FR', 'DE'], 'negate': False, 'variation': 'v3'},
               {'attr': 'age', 'op': 'lt', 'values': [21, 18], 'negate': False, 'variation': 'v0'}]},
    {'key': 'k1', 'country': 'JP', 'age': 20, 'plan': 'free'}],
   ['v0', 'RULE', 0])],
 [('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]),
  ('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 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
target to fallthrough variation still reports TARGET	`['v2', 'TARGET', -1]`	`['v2', 'TARGET', -1]`	Passed
targeting sample 1	`['v0', 'RULE', 1]`	`['v0', 'RULE', 1]`	Passed
targeting sample 2	`['v0', 'FALLTHROUGH', -1]`	`['v0', 'FALLTHROUGH', -1]`	Passed

SHA-256 / fc120fe9e2d302985b002586fc6c4ff10df61eaf7a27ecfa955f474a67b503aa

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 2026-09-29T14:48:51.721403+00:00.

Case digest / 53127227d625c4431a9a0d82d908d0a130aa6c04ad437df7ebf5947e45ea0009