FAILURE MAP
← Case archive

FA-29196 / HTTP redirects / Open access

Compose explicit redirect policy decisions with veto precedence and reason retention: first rejection reason · case 01

Compose explicit redirect policy decisions with veto precedence and reason retention: the first rejection reason branch emits an incorrect decision.

Verified by executionVariant 1 · 7 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The first-rejection-reason decision uses 'next((k for k,v in decisions if v),None)'; this violates the stipulated controller policy.

VERIFIED REPAIR

At this decision use 'next((k for k,v in decisions if not v),None)', preserving the other controller outputs.

Unsuccessful approach: The partial repair uses 'next((k for k,v in reversed(decisions) if not v),None)' and still fails an explicit boundary or control.

Case contract

Compose explicit redirect policy decisions with veto precedence and reason retention. 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, decisions, mode, inspected, override, target):
    return {'request': request, 'decision': [all(v for k,v in decisions), next((k for k,v in decisions if v),None), [k for k,v in decisions if not v], mode == 'follow' and inspected, override and mode != 'error', mode == 'manual', [k for k,v in decisions], target is not None and override, sum(not v for k,v in decisions), inspected and all(v for k,v in decisions)]} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', [['scheme', True], ['host', False], ['port', True]], 'follow', True, False, '/b'), {'request': '/requests/' + str(N) + '/0', 'decision': [False, 'host', ['host'], True, False, False, ['scheme', 'host', 'port'], False, 1, False]})
check('fixture 2', solve('/requests/' + str(N) + '/1', [['scheme', True], ['host', True]], 'manual', False, False, '/c'), {'request': '/requests/' + str(N) + '/1', 'decision': [True, None, [], False, False, True, ['scheme', 'host'], False, 0, False]})
check('fixture 3', solve('/requests/' + str(N) + '/2', [], 'error', True, True, '/d'), {'request': '/requests/' + str(N) + '/2', 'decision': [True, None, [], False, False, False, [], True, 0, True]})
check('fixture 4', solve('/requests/' + str(N) + '/3', [['host', False], ['port', False]], 'follow', True, True, '/e'), {'request': '/requests/' + str(N) + '/3', 'decision': [False, 'host', ['host', 'port'], True, True, False, ['host', 'port'], True, 2, False]})
check('fixture 5', solve('/requests/' + str(N) + '/4', [['scheme', True]], 'follow', False, False, None), {'request': '/requests/' + str(N) + '/4', 'decision': [True, None, [], False, False, False, ['scheme'], False, 0, False]})
check('fixture 6', solve('/requests/' + str(N) + '/5', [['scheme', False], ['host', True]], 'manual', True, True, '/f'), {'request': '/requests/' + str(N) + '/5', 'decision': [False, 'scheme', ['scheme'], False, True, True, ['scheme', 'host'], True, 1, False]})
check('fixture 7', solve('/requests/' + str(N) + '/6', [['x', True]], 'follow', True, True, None), {'request': '/requests/' + str(N) + '/6', 'decision': [True, None, [], True, True, False, ['x'], False, 0, True]})
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': [False, 'scheme', ['host'], True, False, False, ['scheme', 'host', 'port'], False, 1, False], 'request': '/requests/1/0'}{'decision': [False, 'host', ['host'], True, False, False, ['scheme', 'host', 'port'], False, 1, False], 'request': '/requests/1/0'}Failed
fixture 2{'decision': [True, 'scheme', [], False, False, True, ['scheme', 'host'], False, 0, False], 'request': '/requests/1/1'}{'decision': [True, None, [], False, False, True, ['scheme', 'host'], False, 0, False], 'request': '/requests/1/1'}Failed
fixture 3{'decision': [True, None, [], False, False, False, [], True, 0, True], 'request': '/requests/1/2'}{'decision': [True, None, [], False, False, False, [], True, 0, True], 'request': '/requests/1/2'}Passed
fixture 4{'decision': [False, None, ['host', 'port'], True, True, False, ['host', 'port'], True, 2, False], 'request': '/requests/1/3'}{'decision': [False, 'host', ['host', 'port'], True, True, False, ['host', 'port'], True, 2, False], 'request': '/requests/1/3'}Failed
fixture 5{'decision': [True, 'scheme', [], False, False, False, ['scheme'], False, 0, False], 'request': '/requests/1/4'}{'decision': [True, None, [], False, False, False, ['scheme'], False, 0, False], 'request': '/requests/1/4'}Failed
fixture 6{'decision': [False, 'host', ['scheme'], False, True, True, ['scheme', 'host'], True, 1, False], 'request': '/requests/1/5'}{'decision': [False, 'scheme', ['scheme'], False, True, True, ['scheme', 'host'], True, 1, False], 'request': '/requests/1/5'}Failed
fixture 7{'decision': [True, 'x', [], True, True, False, ['x'], False, 0, True], 'request': '/requests/1/6'}{'decision': [True, None, [], True, True, False, ['x'], False, 0, True], 'request': '/requests/1/6'}Failed

SHA-256 / 423c122925d7e02adbca4e39dc3d755be63a9131a270fd07359e206d2115448b

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, decisions, mode, inspected, override, target):
    return {'request': request, 'decision': [all(v for k,v in decisions), next((k for k,v in reversed(decisions) if not v),None), [k for k,v in decisions if not v], mode == 'follow' and inspected, override and mode != 'error', mode == 'manual', [k for k,v in decisions], target is not None and override, sum(not v for k,v in decisions), inspected and all(v for k,v in decisions)]} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', [['scheme', True], ['host', False], ['port', True]], 'follow', True, False, '/b'), {'request': '/requests/' + str(N) + '/0', 'decision': [False, 'host', ['host'], True, False, False, ['scheme', 'host', 'port'], False, 1, False]})
check('fixture 2', solve('/requests/' + str(N) + '/1', [['scheme', True], ['host', True]], 'manual', False, False, '/c'), {'request': '/requests/' + str(N) + '/1', 'decision': [True, None, [], False, False, True, ['scheme', 'host'], False, 0, False]})
check('fixture 3', solve('/requests/' + str(N) + '/2', [], 'error', True, True, '/d'), {'request': '/requests/' + str(N) + '/2', 'decision': [True, None, [], False, False, False, [], True, 0, True]})
check('fixture 4', solve('/requests/' + str(N) + '/3', [['host', False], ['port', False]], 'follow', True, True, '/e'), {'request': '/requests/' + str(N) + '/3', 'decision': [False, 'host', ['host', 'port'], True, True, False, ['host', 'port'], True, 2, False]})
check('fixture 5', solve('/requests/' + str(N) + '/4', [['scheme', True]], 'follow', False, False, None), {'request': '/requests/' + str(N) + '/4', 'decision': [True, None, [], False, False, False, ['scheme'], False, 0, False]})
check('fixture 6', solve('/requests/' + str(N) + '/5', [['scheme', False], ['host', True]], 'manual', True, True, '/f'), {'request': '/requests/' + str(N) + '/5', 'decision': [False, 'scheme', ['scheme'], False, True, True, ['scheme', 'host'], True, 1, False]})
check('fixture 7', solve('/requests/' + str(N) + '/6', [['x', True]], 'follow', True, True, None), {'request': '/requests/' + str(N) + '/6', 'decision': [True, None, [], True, True, False, ['x'], False, 0, True]})
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': [False, 'host', ['host'], True, False, False, ['scheme', 'host', 'port'], False, 1, False], 'request': '/requests/1/0'}{'decision': [False, 'host', ['host'], True, False, False, ['scheme', 'host', 'port'], False, 1, False], 'request': '/requests/1/0'}Passed
fixture 2{'decision': [True, None, [], False, False, True, ['scheme', 'host'], False, 0, False], 'request': '/requests/1/1'}{'decision': [True, None, [], False, False, True, ['scheme', 'host'], False, 0, False], 'request': '/requests/1/1'}Passed
fixture 3{'decision': [True, None, [], False, False, False, [], True, 0, True], 'request': '/requests/1/2'}{'decision': [True, None, [], False, False, False, [], True, 0, True], 'request': '/requests/1/2'}Passed
fixture 4{'decision': [False, 'port', ['host', 'port'], True, True, False, ['host', 'port'], True, 2, False], 'request': '/requests/1/3'}{'decision': [False, 'host', ['host', 'port'], True, True, False, ['host', 'port'], True, 2, False], 'request': '/requests/1/3'}Failed
fixture 5{'decision': [True, None, [], False, False, False, ['scheme'], False, 0, False], 'request': '/requests/1/4'}{'decision': [True, None, [], False, False, False, ['scheme'], False, 0, False], 'request': '/requests/1/4'}Passed
fixture 6{'decision': [False, 'scheme', ['scheme'], False, True, True, ['scheme', 'host'], True, 1, False], 'request': '/requests/1/5'}{'decision': [False, 'scheme', ['scheme'], False, True, True, ['scheme', 'host'], True, 1, False], 'request': '/requests/1/5'}Passed
fixture 7{'decision': [True, None, [], True, True, False, ['x'], False, 0, True], 'request': '/requests/1/6'}{'decision': [True, None, [], True, True, False, ['x'], False, 0, True], 'request': '/requests/1/6'}Passed

SHA-256 / 328985c69ae155067c812155075bc5de15bfc2450002875e6866749d132bc8ea

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, decisions, mode, inspected, override, target):
    return {'request': request, 'decision': [all(v for k,v in decisions), next((k for k,v in decisions if not v),None), [k for k,v in decisions if not v], mode == 'follow' and inspected, override and mode != 'error', mode == 'manual', [k for k,v in decisions], target is not None and override, sum(not v for k,v in decisions), inspected and all(v for k,v in decisions)]} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', [['scheme', True], ['host', False], ['port', True]], 'follow', True, False, '/b'), {'request': '/requests/' + str(N) + '/0', 'decision': [False, 'host', ['host'], True, False, False, ['scheme', 'host', 'port'], False, 1, False]})
check('fixture 2', solve('/requests/' + str(N) + '/1', [['scheme', True], ['host', True]], 'manual', False, False, '/c'), {'request': '/requests/' + str(N) + '/1', 'decision': [True, None, [], False, False, True, ['scheme', 'host'], False, 0, False]})
check('fixture 3', solve('/requests/' + str(N) + '/2', [], 'error', True, True, '/d'), {'request': '/requests/' + str(N) + '/2', 'decision': [True, None, [], False, False, False, [], True, 0, True]})
check('fixture 4', solve('/requests/' + str(N) + '/3', [['host', False], ['port', False]], 'follow', True, True, '/e'), {'request': '/requests/' + str(N) + '/3', 'decision': [False, 'host', ['host', 'port'], True, True, False, ['host', 'port'], True, 2, False]})
check('fixture 5', solve('/requests/' + str(N) + '/4', [['scheme', True]], 'follow', False, False, None), {'request': '/requests/' + str(N) + '/4', 'decision': [True, None, [], False, False, False, ['scheme'], False, 0, False]})
check('fixture 6', solve('/requests/' + str(N) + '/5', [['scheme', False], ['host', True]], 'manual', True, True, '/f'), {'request': '/requests/' + str(N) + '/5', 'decision': [False, 'scheme', ['scheme'], False, True, True, ['scheme', 'host'], True, 1, False]})
check('fixture 7', solve('/requests/' + str(N) + '/6', [['x', True]], 'follow', True, True, None), {'request': '/requests/' + str(N) + '/6', 'decision': [True, None, [], True, True, False, ['x'], False, 0, True]})
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': [False, 'host', ['host'], True, False, False, ['scheme', 'host', 'port'], False, 1, False], 'request': '/requests/1/0'}{'decision': [False, 'host', ['host'], True, False, False, ['scheme', 'host', 'port'], False, 1, False], 'request': '/requests/1/0'}Passed
fixture 2{'decision': [True, None, [], False, False, True, ['scheme', 'host'], False, 0, False], 'request': '/requests/1/1'}{'decision': [True, None, [], False, False, True, ['scheme', 'host'], False, 0, False], 'request': '/requests/1/1'}Passed
fixture 3{'decision': [True, None, [], False, False, False, [], True, 0, True], 'request': '/requests/1/2'}{'decision': [True, None, [], False, False, False, [], True, 0, True], 'request': '/requests/1/2'}Passed
fixture 4{'decision': [False, 'host', ['host', 'port'], True, True, False, ['host', 'port'], True, 2, False], 'request': '/requests/1/3'}{'decision': [False, 'host', ['host', 'port'], True, True, False, ['host', 'port'], True, 2, False], 'request': '/requests/1/3'}Passed
fixture 5{'decision': [True, None, [], False, False, False, ['scheme'], False, 0, False], 'request': '/requests/1/4'}{'decision': [True, None, [], False, False, False, ['scheme'], False, 0, False], 'request': '/requests/1/4'}Passed
fixture 6{'decision': [False, 'scheme', ['scheme'], False, True, True, ['scheme', 'host'], True, 1, False], 'request': '/requests/1/5'}{'decision': [False, 'scheme', ['scheme'], False, True, True, ['scheme', 'host'], True, 1, False], 'request': '/requests/1/5'}Passed
fixture 7{'decision': [True, None, [], True, True, False, ['x'], False, 0, True], 'request': '/requests/1/6'}{'decision': [True, None, [], True, True, False, ['x'], False, 0, True], 'request': '/requests/1/6'}Passed

SHA-256 / fb563b1f5f08ef10911f65f17f57dbebd0f4556acb5033f9c14fe03e177e65e1

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 2026-09-29T14:41:40.851221+00:00.

Case digest / 1fd12f0229689d6353e989fb6c7418c2bbb13705bc79fbfe0696ccc0919a01be