FAILURE MAP
← Case archive

FA-29146 / HTTP redirects / Open access

Extract redirect route captures under an explicit segment-matching grammar: segment wildcard not slash · case 01

Extract redirect route captures under an explicit segment-matching grammar: the segment wildcard not slash branch emits an incorrect decision.

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

ROOT CAUSE

The segment-wildcard-not-slash decision uses "'/'.join(segments[1:])"; this violates the stipulated controller policy.

VERIFIED REPAIR

At this decision use 'segments[1] if len(segments)>1 else None', preserving the other controller outputs.

Unsuccessful approach: The partial repair uses 'segments[-1] if segments else None' and still fails an explicit boundary or control.

Case contract

Extract redirect route captures under an explicit segment-matching grammar. 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, path, prefix, segments, greedy, case_sensitive, suffix):
    return {'request': request, 'decision': [path[len(prefix):] if path.startswith(prefix) else None, '/'.join(segments[1:]), '/'.join(segments[1:]) if greedy else (segments[1] if len(segments)>1 else ''), path.startswith(prefix) if case_sensitive else path.lower().startswith(prefix.lower()), segments, path[:-len(suffix)] if suffix and path.endswith(suffix) else path, '.' in path, segments[1:], len(segments), greedy and len(segments)>1]} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', '/api/a/b', '/api', ['api', 'a', 'b'], True, True, '.json'), {'request': '/requests/' + str(N) + '/0', 'decision': ['/a/b', 'a', 'a/b', True, ['api', 'a', 'b'], '/api/a/b', False, ['a', 'b'], 3, True]})
check('fixture 2', solve('/requests/' + str(N) + '/1', '/API/a', '/api', ['API', 'a'], False, False, ''), {'request': '/requests/' + str(N) + '/1', 'decision': [None, 'a', 'a', True, ['API', 'a'], '/API/a', False, ['a'], 2, False]})
check('fixture 3', solve('/requests/' + str(N) + '/2', '/api', '/api', ['api'], True, True, ''), {'request': '/requests/' + str(N) + '/2', 'decision': ['', None, '', True, ['api'], '/api', False, [], 1, False]})
check('fixture 4', solve('/requests/' + str(N) + '/3', '/apix/a', '/api', ['apix', 'a'], False, True, '.txt'), {'request': '/requests/' + str(N) + '/3', 'decision': ['x/a', 'a', 'a', True, ['apix', 'a'], '/apix/a', False, ['a'], 2, False]})
check('fixture 5', solve('/requests/' + str(N) + '/4', '/api/a//b/', '/api', ['api', 'a', '', 'b', ''], True, True, '/'), {'request': '/requests/' + str(N) + '/4', 'decision': ['/a//b/', 'a', 'a//b/', True, ['api', 'a', '', 'b', ''], '/api/a//b', False, ['a', '', 'b', ''], 5, True]})
check('fixture 6', solve('/requests/' + str(N) + '/5', '/api/a.json', '/api', ['api', 'a.json'], False, True, '.json'), {'request': '/requests/' + str(N) + '/5', 'decision': ['/a.json', 'a.json', 'a.json', True, ['api', 'a.json'], '/api/a', True, ['a.json'], 2, False]})
check('fixture 7', solve('/requests/' + str(N) + '/6', '/API/a', '/api', ['API', 'a'], False, True, ''), {'request': '/requests/' + str(N) + '/6', 'decision': [None, 'a', 'a', False, ['API', 'a'], '/API/a', False, ['a'], 2, 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': ['/a/b', 'a/b', 'a/b', True, ['api', 'a', 'b'], '/api/a/b', False, ['a', 'b'], 3, True], 'request': '/requests/1/0'}{'decision': ['/a/b', 'a', 'a/b', True, ['api', 'a', 'b'], '/api/a/b', False, ['a', 'b'], 3, True], 'request': '/requests/1/0'}Failed
fixture 2{'decision': [None, 'a', 'a', True, ['API', 'a'], '/API/a', False, ['a'], 2, False], 'request': '/requests/1/1'}{'decision': [None, 'a', 'a', True, ['API', 'a'], '/API/a', False, ['a'], 2, False], 'request': '/requests/1/1'}Passed
fixture 3{'decision': ['', '', '', True, ['api'], '/api', False, [], 1, False], 'request': '/requests/1/2'}{'decision': ['', None, '', True, ['api'], '/api', False, [], 1, False], 'request': '/requests/1/2'}Failed
fixture 4{'decision': ['x/a', 'a', 'a', True, ['apix', 'a'], '/apix/a', False, ['a'], 2, False], 'request': '/requests/1/3'}{'decision': ['x/a', 'a', 'a', True, ['apix', 'a'], '/apix/a', False, ['a'], 2, False], 'request': '/requests/1/3'}Passed
fixture 5{'decision': ['/a//b/', 'a//b/', 'a//b/', True, ['api', 'a', '', 'b', ''], '/api/a//b', False, ['a', '', 'b', ''], 5, True], 'request': '/requests/1/4'}{'decision': ['/a//b/', 'a', 'a//b/', True, ['api', 'a', '', 'b', ''], '/api/a//b', False, ['a', '', 'b', ''], 5, True], 'request': '/requests/1/4'}Failed
fixture 6{'decision': ['/a.json', 'a.json', 'a.json', True, ['api', 'a.json'], '/api/a', True, ['a.json'], 2, False], 'request': '/requests/1/5'}{'decision': ['/a.json', 'a.json', 'a.json', True, ['api', 'a.json'], '/api/a', True, ['a.json'], 2, False], 'request': '/requests/1/5'}Passed
fixture 7{'decision': [None, 'a', 'a', False, ['API', 'a'], '/API/a', False, ['a'], 2, False], 'request': '/requests/1/6'}{'decision': [None, 'a', 'a', False, ['API', 'a'], '/API/a', False, ['a'], 2, False], 'request': '/requests/1/6'}Passed

SHA-256 / 45c7f81444e9cd7353e266913ee3b46a5a118661487742a18fc1997650645953

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, path, prefix, segments, greedy, case_sensitive, suffix):
    return {'request': request, 'decision': [path[len(prefix):] if path.startswith(prefix) else None, segments[-1] if segments else None, '/'.join(segments[1:]) if greedy else (segments[1] if len(segments)>1 else ''), path.startswith(prefix) if case_sensitive else path.lower().startswith(prefix.lower()), segments, path[:-len(suffix)] if suffix and path.endswith(suffix) else path, '.' in path, segments[1:], len(segments), greedy and len(segments)>1]} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', '/api/a/b', '/api', ['api', 'a', 'b'], True, True, '.json'), {'request': '/requests/' + str(N) + '/0', 'decision': ['/a/b', 'a', 'a/b', True, ['api', 'a', 'b'], '/api/a/b', False, ['a', 'b'], 3, True]})
check('fixture 2', solve('/requests/' + str(N) + '/1', '/API/a', '/api', ['API', 'a'], False, False, ''), {'request': '/requests/' + str(N) + '/1', 'decision': [None, 'a', 'a', True, ['API', 'a'], '/API/a', False, ['a'], 2, False]})
check('fixture 3', solve('/requests/' + str(N) + '/2', '/api', '/api', ['api'], True, True, ''), {'request': '/requests/' + str(N) + '/2', 'decision': ['', None, '', True, ['api'], '/api', False, [], 1, False]})
check('fixture 4', solve('/requests/' + str(N) + '/3', '/apix/a', '/api', ['apix', 'a'], False, True, '.txt'), {'request': '/requests/' + str(N) + '/3', 'decision': ['x/a', 'a', 'a', True, ['apix', 'a'], '/apix/a', False, ['a'], 2, False]})
check('fixture 5', solve('/requests/' + str(N) + '/4', '/api/a//b/', '/api', ['api', 'a', '', 'b', ''], True, True, '/'), {'request': '/requests/' + str(N) + '/4', 'decision': ['/a//b/', 'a', 'a//b/', True, ['api', 'a', '', 'b', ''], '/api/a//b', False, ['a', '', 'b', ''], 5, True]})
check('fixture 6', solve('/requests/' + str(N) + '/5', '/api/a.json', '/api', ['api', 'a.json'], False, True, '.json'), {'request': '/requests/' + str(N) + '/5', 'decision': ['/a.json', 'a.json', 'a.json', True, ['api', 'a.json'], '/api/a', True, ['a.json'], 2, False]})
check('fixture 7', solve('/requests/' + str(N) + '/6', '/API/a', '/api', ['API', 'a'], False, True, ''), {'request': '/requests/' + str(N) + '/6', 'decision': [None, 'a', 'a', False, ['API', 'a'], '/API/a', False, ['a'], 2, 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': ['/a/b', 'b', 'a/b', True, ['api', 'a', 'b'], '/api/a/b', False, ['a', 'b'], 3, True], 'request': '/requests/1/0'}{'decision': ['/a/b', 'a', 'a/b', True, ['api', 'a', 'b'], '/api/a/b', False, ['a', 'b'], 3, True], 'request': '/requests/1/0'}Failed
fixture 2{'decision': [None, 'a', 'a', True, ['API', 'a'], '/API/a', False, ['a'], 2, False], 'request': '/requests/1/1'}{'decision': [None, 'a', 'a', True, ['API', 'a'], '/API/a', False, ['a'], 2, False], 'request': '/requests/1/1'}Passed
fixture 3{'decision': ['', 'api', '', True, ['api'], '/api', False, [], 1, False], 'request': '/requests/1/2'}{'decision': ['', None, '', True, ['api'], '/api', False, [], 1, False], 'request': '/requests/1/2'}Failed
fixture 4{'decision': ['x/a', 'a', 'a', True, ['apix', 'a'], '/apix/a', False, ['a'], 2, False], 'request': '/requests/1/3'}{'decision': ['x/a', 'a', 'a', True, ['apix', 'a'], '/apix/a', False, ['a'], 2, False], 'request': '/requests/1/3'}Passed
fixture 5{'decision': ['/a//b/', '', 'a//b/', True, ['api', 'a', '', 'b', ''], '/api/a//b', False, ['a', '', 'b', ''], 5, True], 'request': '/requests/1/4'}{'decision': ['/a//b/', 'a', 'a//b/', True, ['api', 'a', '', 'b', ''], '/api/a//b', False, ['a', '', 'b', ''], 5, True], 'request': '/requests/1/4'}Failed
fixture 6{'decision': ['/a.json', 'a.json', 'a.json', True, ['api', 'a.json'], '/api/a', True, ['a.json'], 2, False], 'request': '/requests/1/5'}{'decision': ['/a.json', 'a.json', 'a.json', True, ['api', 'a.json'], '/api/a', True, ['a.json'], 2, False], 'request': '/requests/1/5'}Passed
fixture 7{'decision': [None, 'a', 'a', False, ['API', 'a'], '/API/a', False, ['a'], 2, False], 'request': '/requests/1/6'}{'decision': [None, 'a', 'a', False, ['API', 'a'], '/API/a', False, ['a'], 2, False], 'request': '/requests/1/6'}Passed

SHA-256 / 84607ab16b78194bb7cf1111dadddc92eb76b7a26ca6dd7c482e75cd1eba0bc8

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, path, prefix, segments, greedy, case_sensitive, suffix):
    return {'request': request, 'decision': [path[len(prefix):] if path.startswith(prefix) else None, segments[1] if len(segments)>1 else None, '/'.join(segments[1:]) if greedy else (segments[1] if len(segments)>1 else ''), path.startswith(prefix) if case_sensitive else path.lower().startswith(prefix.lower()), segments, path[:-len(suffix)] if suffix and path.endswith(suffix) else path, '.' in path, segments[1:], len(segments), greedy and len(segments)>1]} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', '/api/a/b', '/api', ['api', 'a', 'b'], True, True, '.json'), {'request': '/requests/' + str(N) + '/0', 'decision': ['/a/b', 'a', 'a/b', True, ['api', 'a', 'b'], '/api/a/b', False, ['a', 'b'], 3, True]})
check('fixture 2', solve('/requests/' + str(N) + '/1', '/API/a', '/api', ['API', 'a'], False, False, ''), {'request': '/requests/' + str(N) + '/1', 'decision': [None, 'a', 'a', True, ['API', 'a'], '/API/a', False, ['a'], 2, False]})
check('fixture 3', solve('/requests/' + str(N) + '/2', '/api', '/api', ['api'], True, True, ''), {'request': '/requests/' + str(N) + '/2', 'decision': ['', None, '', True, ['api'], '/api', False, [], 1, False]})
check('fixture 4', solve('/requests/' + str(N) + '/3', '/apix/a', '/api', ['apix', 'a'], False, True, '.txt'), {'request': '/requests/' + str(N) + '/3', 'decision': ['x/a', 'a', 'a', True, ['apix', 'a'], '/apix/a', False, ['a'], 2, False]})
check('fixture 5', solve('/requests/' + str(N) + '/4', '/api/a//b/', '/api', ['api', 'a', '', 'b', ''], True, True, '/'), {'request': '/requests/' + str(N) + '/4', 'decision': ['/a//b/', 'a', 'a//b/', True, ['api', 'a', '', 'b', ''], '/api/a//b', False, ['a', '', 'b', ''], 5, True]})
check('fixture 6', solve('/requests/' + str(N) + '/5', '/api/a.json', '/api', ['api', 'a.json'], False, True, '.json'), {'request': '/requests/' + str(N) + '/5', 'decision': ['/a.json', 'a.json', 'a.json', True, ['api', 'a.json'], '/api/a', True, ['a.json'], 2, False]})
check('fixture 7', solve('/requests/' + str(N) + '/6', '/API/a', '/api', ['API', 'a'], False, True, ''), {'request': '/requests/' + str(N) + '/6', 'decision': [None, 'a', 'a', False, ['API', 'a'], '/API/a', False, ['a'], 2, 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': ['/a/b', 'a', 'a/b', True, ['api', 'a', 'b'], '/api/a/b', False, ['a', 'b'], 3, True], 'request': '/requests/1/0'}{'decision': ['/a/b', 'a', 'a/b', True, ['api', 'a', 'b'], '/api/a/b', False, ['a', 'b'], 3, True], 'request': '/requests/1/0'}Passed
fixture 2{'decision': [None, 'a', 'a', True, ['API', 'a'], '/API/a', False, ['a'], 2, False], 'request': '/requests/1/1'}{'decision': [None, 'a', 'a', True, ['API', 'a'], '/API/a', False, ['a'], 2, False], 'request': '/requests/1/1'}Passed
fixture 3{'decision': ['', None, '', True, ['api'], '/api', False, [], 1, False], 'request': '/requests/1/2'}{'decision': ['', None, '', True, ['api'], '/api', False, [], 1, False], 'request': '/requests/1/2'}Passed
fixture 4{'decision': ['x/a', 'a', 'a', True, ['apix', 'a'], '/apix/a', False, ['a'], 2, False], 'request': '/requests/1/3'}{'decision': ['x/a', 'a', 'a', True, ['apix', 'a'], '/apix/a', False, ['a'], 2, False], 'request': '/requests/1/3'}Passed
fixture 5{'decision': ['/a//b/', 'a', 'a//b/', True, ['api', 'a', '', 'b', ''], '/api/a//b', False, ['a', '', 'b', ''], 5, True], 'request': '/requests/1/4'}{'decision': ['/a//b/', 'a', 'a//b/', True, ['api', 'a', '', 'b', ''], '/api/a//b', False, ['a', '', 'b', ''], 5, True], 'request': '/requests/1/4'}Passed
fixture 6{'decision': ['/a.json', 'a.json', 'a.json', True, ['api', 'a.json'], '/api/a', True, ['a.json'], 2, False], 'request': '/requests/1/5'}{'decision': ['/a.json', 'a.json', 'a.json', True, ['api', 'a.json'], '/api/a', True, ['a.json'], 2, False], 'request': '/requests/1/5'}Passed
fixture 7{'decision': [None, 'a', 'a', False, ['API', 'a'], '/API/a', False, ['a'], 2, False], 'request': '/requests/1/6'}{'decision': [None, 'a', 'a', False, ['API', 'a'], '/API/a', False, ['a'], 2, False], 'request': '/requests/1/6'}Passed

SHA-256 / 465e4c59b54316d0d35460eaa77cab148ce48321e5041341c6e129e08398745e

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 2026-09-29T14:41:40.354662+00:00.

Case digest / 2baec369308693e3497ad82224c10e4574df04b1ecd2a2b238fa7fea89a41b2d