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FA-28446 / HTTP redirects / Open access

Resolve stored redirect chains with per-entry freshness and provenance: first stale entry · case 01

Resolve stored redirect chains with per-entry freshness and provenance: the first stale entry branch emits an incorrect decision.

Verified by executionVariant 1 · 6 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The first-stale-entry decision uses 'next((i for i,f in enumerate(fresh) if f),None)'; this violates the stipulated controller policy.

VERIFIED REPAIR

At this decision use 'next((i for i,f in enumerate(fresh) if not f),None)', preserving the other controller outputs.

Unsuccessful approach: The partial repair uses 'len(fresh)-1 if fresh and not fresh[-1] else None' and still fails an explicit boundary or control.

Case contract

Resolve stored redirect chains with per-entry freshness and provenance. The explicit fixture inputs and outputs define a bounded offline policy; request identity must accompany the decision.

Why this case matters

Models a redirect controller decision before following a target or exposing a redirect result.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
from urllib.parse import urlsplit, unquote, quote
import posixpath
import re
N = 1
observations = []
def solve(request, targets, fresh, network, blocked, now, inserted):
    return {'request': request, 'decision': [targets, next((i for i,f in enumerate(fresh) if f),None), all(fresh), max(0,now-inserted), 'network' if network else 'cache', blocked and not network, targets[0] if targets else None, len(targets), not targets, targets[:next((i for i,f in enumerate(fresh) if not f),len(fresh))]]} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', ['/b', '/c'], [True, False], False, False, 20, 10), {'request': '/requests/' + str(N) + '/0', 'decision': [['/b', '/c'], 1, False, 10, 'cache', False, '/b', 2, False, ['/b']]})
check('fixture 2', solve('/requests/' + str(N) + '/1', ['/b'], [True], True, False, 10, 10), {'request': '/requests/' + str(N) + '/1', 'decision': [['/b'], None, True, 0, 'network', False, '/b', 1, False, ['/b']]})
check('fixture 3', solve('/requests/' + str(N) + '/2', [], [], True, False, 0, 0), {'request': '/requests/' + str(N) + '/2', 'decision': [[], None, True, 0, 'network', False, None, 0, True, []]})
check('fixture 4', solve('/requests/' + str(N) + '/3', ['/z', '/a'], [True, True], False, True, 30, 5), {'request': '/requests/' + str(N) + '/3', 'decision': [['/z', '/a'], None, True, 25, 'cache', True, '/z', 2, False, ['/z', '/a']]})
check('fixture 5', solve('/requests/' + str(N) + '/4', ['/a', '/a'], [False, True], False, False, 8, 9), {'request': '/requests/' + str(N) + '/4', 'decision': [['/a', '/a'], 0, False, 0, 'cache', False, '/a', 2, False, []]})
check('fixture 6', solve('/requests/' + str(N) + '/5', ['/q'], [False], True, True, 100, 80), {'request': '/requests/' + str(N) + '/5', 'decision': [['/q'], 0, False, 20, 'network', False, '/q', 1, False, []]})
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
fixture 1{'decision': [['/b', '/c'], 0, False, 10, 'cache', False, '/b', 2, False, ['/b']], 'request': '/requests/1/0'}{'decision': [['/b', '/c'], 1, False, 10, 'cache', False, '/b', 2, False, ['/b']], 'request': '/requests/1/0'}Failed
fixture 2{'decision': [['/b'], 0, True, 0, 'network', False, '/b', 1, False, ['/b']], 'request': '/requests/1/1'}{'decision': [['/b'], None, True, 0, 'network', False, '/b', 1, False, ['/b']], 'request': '/requests/1/1'}Failed
fixture 3{'decision': [[], None, True, 0, 'network', False, None, 0, True, []], 'request': '/requests/1/2'}{'decision': [[], None, True, 0, 'network', False, None, 0, True, []], 'request': '/requests/1/2'}Passed
fixture 4{'decision': [['/z', '/a'], 0, True, 25, 'cache', True, '/z', 2, False, ['/z', '/a']], 'request': '/requests/1/3'}{'decision': [['/z', '/a'], None, True, 25, 'cache', True, '/z', 2, False, ['/z', '/a']], 'request': '/requests/1/3'}Failed
fixture 5{'decision': [['/a', '/a'], 1, False, 0, 'cache', False, '/a', 2, False, []], 'request': '/requests/1/4'}{'decision': [['/a', '/a'], 0, False, 0, 'cache', False, '/a', 2, False, []], 'request': '/requests/1/4'}Failed
fixture 6{'decision': [['/q'], None, False, 20, 'network', False, '/q', 1, False, []], 'request': '/requests/1/5'}{'decision': [['/q'], 0, False, 20, 'network', False, '/q', 1, False, []], 'request': '/requests/1/5'}Failed

SHA-256 / 8f3607aff20034ed7f871352a4ec235e078106e2a188d0706f079b85390eb45e

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
from urllib.parse import urlsplit, unquote, quote
import posixpath
import re
N = 1
observations = []
def solve(request, targets, fresh, network, blocked, now, inserted):
    return {'request': request, 'decision': [targets, len(fresh)-1 if fresh and not fresh[-1] else None, all(fresh), max(0,now-inserted), 'network' if network else 'cache', blocked and not network, targets[0] if targets else None, len(targets), not targets, targets[:next((i for i,f in enumerate(fresh) if not f),len(fresh))]]} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', ['/b', '/c'], [True, False], False, False, 20, 10), {'request': '/requests/' + str(N) + '/0', 'decision': [['/b', '/c'], 1, False, 10, 'cache', False, '/b', 2, False, ['/b']]})
check('fixture 2', solve('/requests/' + str(N) + '/1', ['/b'], [True], True, False, 10, 10), {'request': '/requests/' + str(N) + '/1', 'decision': [['/b'], None, True, 0, 'network', False, '/b', 1, False, ['/b']]})
check('fixture 3', solve('/requests/' + str(N) + '/2', [], [], True, False, 0, 0), {'request': '/requests/' + str(N) + '/2', 'decision': [[], None, True, 0, 'network', False, None, 0, True, []]})
check('fixture 4', solve('/requests/' + str(N) + '/3', ['/z', '/a'], [True, True], False, True, 30, 5), {'request': '/requests/' + str(N) + '/3', 'decision': [['/z', '/a'], None, True, 25, 'cache', True, '/z', 2, False, ['/z', '/a']]})
check('fixture 5', solve('/requests/' + str(N) + '/4', ['/a', '/a'], [False, True], False, False, 8, 9), {'request': '/requests/' + str(N) + '/4', 'decision': [['/a', '/a'], 0, False, 0, 'cache', False, '/a', 2, False, []]})
check('fixture 6', solve('/requests/' + str(N) + '/5', ['/q'], [False], True, True, 100, 80), {'request': '/requests/' + str(N) + '/5', 'decision': [['/q'], 0, False, 20, 'network', False, '/q', 1, False, []]})
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
fixture 1{'decision': [['/b', '/c'], 1, False, 10, 'cache', False, '/b', 2, False, ['/b']], 'request': '/requests/1/0'}{'decision': [['/b', '/c'], 1, False, 10, 'cache', False, '/b', 2, False, ['/b']], 'request': '/requests/1/0'}Passed
fixture 2{'decision': [['/b'], None, True, 0, 'network', False, '/b', 1, False, ['/b']], 'request': '/requests/1/1'}{'decision': [['/b'], None, True, 0, 'network', False, '/b', 1, False, ['/b']], 'request': '/requests/1/1'}Passed
fixture 3{'decision': [[], None, True, 0, 'network', False, None, 0, True, []], 'request': '/requests/1/2'}{'decision': [[], None, True, 0, 'network', False, None, 0, True, []], 'request': '/requests/1/2'}Passed
fixture 4{'decision': [['/z', '/a'], None, True, 25, 'cache', True, '/z', 2, False, ['/z', '/a']], 'request': '/requests/1/3'}{'decision': [['/z', '/a'], None, True, 25, 'cache', True, '/z', 2, False, ['/z', '/a']], 'request': '/requests/1/3'}Passed
fixture 5{'decision': [['/a', '/a'], None, False, 0, 'cache', False, '/a', 2, False, []], 'request': '/requests/1/4'}{'decision': [['/a', '/a'], 0, False, 0, 'cache', False, '/a', 2, False, []], 'request': '/requests/1/4'}Failed
fixture 6{'decision': [['/q'], 0, False, 20, 'network', False, '/q', 1, False, []], 'request': '/requests/1/5'}{'decision': [['/q'], 0, False, 20, 'network', False, '/q', 1, False, []], 'request': '/requests/1/5'}Passed

SHA-256 / 35aca283ff9035d004852bee960168136c8410d5529554466cc191d005845f34

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json
from urllib.parse import urlsplit, unquote, quote
import posixpath
import re
N = 1
observations = []
def solve(request, targets, fresh, network, blocked, now, inserted):
    return {'request': request, 'decision': [targets, next((i for i,f in enumerate(fresh) if not f),None), all(fresh), max(0,now-inserted), 'network' if network else 'cache', blocked and not network, targets[0] if targets else None, len(targets), not targets, targets[:next((i for i,f in enumerate(fresh) if not f),len(fresh))]]} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', ['/b', '/c'], [True, False], False, False, 20, 10), {'request': '/requests/' + str(N) + '/0', 'decision': [['/b', '/c'], 1, False, 10, 'cache', False, '/b', 2, False, ['/b']]})
check('fixture 2', solve('/requests/' + str(N) + '/1', ['/b'], [True], True, False, 10, 10), {'request': '/requests/' + str(N) + '/1', 'decision': [['/b'], None, True, 0, 'network', False, '/b', 1, False, ['/b']]})
check('fixture 3', solve('/requests/' + str(N) + '/2', [], [], True, False, 0, 0), {'request': '/requests/' + str(N) + '/2', 'decision': [[], None, True, 0, 'network', False, None, 0, True, []]})
check('fixture 4', solve('/requests/' + str(N) + '/3', ['/z', '/a'], [True, True], False, True, 30, 5), {'request': '/requests/' + str(N) + '/3', 'decision': [['/z', '/a'], None, True, 25, 'cache', True, '/z', 2, False, ['/z', '/a']]})
check('fixture 5', solve('/requests/' + str(N) + '/4', ['/a', '/a'], [False, True], False, False, 8, 9), {'request': '/requests/' + str(N) + '/4', 'decision': [['/a', '/a'], 0, False, 0, 'cache', False, '/a', 2, False, []]})
check('fixture 6', solve('/requests/' + str(N) + '/5', ['/q'], [False], True, True, 100, 80), {'request': '/requests/' + str(N) + '/5', 'decision': [['/q'], 0, False, 20, 'network', False, '/q', 1, False, []]})
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
fixture 1{'decision': [['/b', '/c'], 1, False, 10, 'cache', False, '/b', 2, False, ['/b']], 'request': '/requests/1/0'}{'decision': [['/b', '/c'], 1, False, 10, 'cache', False, '/b', 2, False, ['/b']], 'request': '/requests/1/0'}Passed
fixture 2{'decision': [['/b'], None, True, 0, 'network', False, '/b', 1, False, ['/b']], 'request': '/requests/1/1'}{'decision': [['/b'], None, True, 0, 'network', False, '/b', 1, False, ['/b']], 'request': '/requests/1/1'}Passed
fixture 3{'decision': [[], None, True, 0, 'network', False, None, 0, True, []], 'request': '/requests/1/2'}{'decision': [[], None, True, 0, 'network', False, None, 0, True, []], 'request': '/requests/1/2'}Passed
fixture 4{'decision': [['/z', '/a'], None, True, 25, 'cache', True, '/z', 2, False, ['/z', '/a']], 'request': '/requests/1/3'}{'decision': [['/z', '/a'], None, True, 25, 'cache', True, '/z', 2, False, ['/z', '/a']], 'request': '/requests/1/3'}Passed
fixture 5{'decision': [['/a', '/a'], 0, False, 0, 'cache', False, '/a', 2, False, []], 'request': '/requests/1/4'}{'decision': [['/a', '/a'], 0, False, 0, 'cache', False, '/a', 2, False, []], 'request': '/requests/1/4'}Passed
fixture 6{'decision': [['/q'], 0, False, 20, 'network', False, '/q', 1, False, []], 'request': '/requests/1/5'}{'decision': [['/q'], 0, False, 20, 'network', False, '/q', 1, False, []], 'request': '/requests/1/5'}Passed

SHA-256 / 52bb7bcb7bad9f080ed733e2adb1727223b437a99de3ef7029a88456a4753fcd

Verification & scope

Stipulated offline redirect policy, not a complete HTTP, browser, URL, cache, or security implementation. Numbered variants vary request correlation identity. 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 2026-09-29T14:41:33.928033+00:00.

Case digest / 423c4143e3d162e64fc980f808527009dc8943f93d0a191bd7570b8404cd7730