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FA-28496 / HTTP redirects / Open access

Select a redirect rule by explicit priority, specificity and declaration order: method filter · case 01

Select a redirect rule by explicit priority, specificity and declaration order: the method filter branch emits an incorrect decision.

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

ROOT CAUSE

The method-filter decision uses '[r[3] for r in rules]'; this violates the stipulated controller policy.

THE FAILURE

The method-filter decision uses '[r[3] for r in rules]'; this violates the stipulated controller policy.

Unsuccessful approach: The partial repair uses "[r[3] for r in rules if r[2]=='GET']" and still fails an explicit boundary or control.

Case contract

Select a redirect rule by explicit priority, specificity and declaration order. 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, rules, path, method):
    return {'request': request, 'decision': [[r[3] for r in rules if r[0]==path], [r[3] for r in rules], [r[3] for r in sorted(rules,key=lambda r:r[1])], [r[3] for r in rules], next((r[3] for r in sorted(rules,key=lambda r:r[1]) if r[0]==path and r[2]==method),None), len(rules), sum(r[0]==path and r[2]==method for r in rules), method == 'HEAD', [r[3] for r in sorted(rules,key=lambda r:r[1]) if r[0]==path and r[2]==method][1:], not any(r[0]==path and r[2]==method for r in rules)]} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', [['/a', 3, 'GET', '/x'], ['/a', 1, 'GET', '/y']], '/a', 'GET'), {'request': '/requests/' + str(N) + '/0', 'decision': [['/x', '/y'], ['/x', '/y'], ['/y', '/x'], ['/x', '/y'], '/y', 2, 2, False, ['/x'], False]})
check('fixture 2', solve('/requests/' + str(N) + '/1', [['/a', 1, 'POST', '/p'], ['/a', 2, 'GET', '/g']], '/a', 'GET'), {'request': '/requests/' + str(N) + '/1', 'decision': [['/p', '/g'], ['/g'], ['/p', '/g'], ['/p', '/g'], '/g', 2, 1, False, [], False]})
check('fixture 3', solve('/requests/' + str(N) + '/2', [['/b', 1, 'GET', '/b'], ['/a', 1, 'GET', '/a']], '/a', 'GET'), {'request': '/requests/' + str(N) + '/2', 'decision': [['/a'], ['/b', '/a'], ['/b', '/a'], ['/b', '/a'], '/a', 2, 1, False, [], False]})
check('fixture 4', solve('/requests/' + str(N) + '/3', [['/a', 1, 'GET', '/x'], ['/a', 1, 'GET', '/y']], '/a', 'GET'), {'request': '/requests/' + str(N) + '/3', 'decision': [['/x', '/y'], ['/x', '/y'], ['/x', '/y'], ['/x', '/y'], '/x', 2, 2, False, ['/y'], False]})
check('fixture 5', solve('/requests/' + str(N) + '/4', [], '/a', 'GET'), {'request': '/requests/' + str(N) + '/4', 'decision': [[], [], [], [], None, 0, 0, False, [], True]})
check('fixture 6', solve('/requests/' + str(N) + '/5', [['/a', 1, 'HEAD', '/h'], ['/ab', 0, 'GET', '/q']], '/ab', 'HEAD'), {'request': '/requests/' + str(N) + '/5', 'decision': [['/q'], ['/h'], ['/q', '/h'], ['/h', '/q'], None, 2, 0, True, [], 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': [['/x', '/y'], ['/x', '/y'], ['/y', '/x'], ['/x', '/y'], '/y', 2, 2, False, ['/x'], False], 'request': '/requests/1/0'}{'decision': [['/x', '/y'], ['/x', '/y'], ['/y', '/x'], ['/x', '/y'], '/y', 2, 2, False, ['/x'], False], 'request': '/requests/1/0'}Passed
fixture 2{'decision': [['/p', '/g'], ['/p', '/g'], ['/p', '/g'], ['/p', '/g'], '/g', 2, 1, False, [], False], 'request': '/requests/1/1'}{'decision': [['/p', '/g'], ['/g'], ['/p', '/g'], ['/p', '/g'], '/g', 2, 1, False, [], False], 'request': '/requests/1/1'}Failed
fixture 3{'decision': [['/a'], ['/b', '/a'], ['/b', '/a'], ['/b', '/a'], '/a', 2, 1, False, [], False], 'request': '/requests/1/2'}{'decision': [['/a'], ['/b', '/a'], ['/b', '/a'], ['/b', '/a'], '/a', 2, 1, False, [], False], 'request': '/requests/1/2'}Passed
fixture 4{'decision': [['/x', '/y'], ['/x', '/y'], ['/x', '/y'], ['/x', '/y'], '/x', 2, 2, False, ['/y'], False], 'request': '/requests/1/3'}{'decision': [['/x', '/y'], ['/x', '/y'], ['/x', '/y'], ['/x', '/y'], '/x', 2, 2, False, ['/y'], False], 'request': '/requests/1/3'}Passed
fixture 5{'decision': [[], [], [], [], None, 0, 0, False, [], True], 'request': '/requests/1/4'}{'decision': [[], [], [], [], None, 0, 0, False, [], True], 'request': '/requests/1/4'}Passed
fixture 6{'decision': [['/q'], ['/h', '/q'], ['/q', '/h'], ['/h', '/q'], None, 2, 0, True, [], True], 'request': '/requests/1/5'}{'decision': [['/q'], ['/h'], ['/q', '/h'], ['/h', '/q'], None, 2, 0, True, [], True], 'request': '/requests/1/5'}Failed

SHA-256 / e0e34abef9d2d38f9b9e082d127b3f1054f09139753d3de04c66ad8fca7b1bf8

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, rules, path, method):
    return {'request': request, 'decision': [[r[3] for r in rules if r[0]==path], [r[3] for r in rules if r[2]=='GET'], [r[3] for r in sorted(rules,key=lambda r:r[1])], [r[3] for r in rules], next((r[3] for r in sorted(rules,key=lambda r:r[1]) if r[0]==path and r[2]==method),None), len(rules), sum(r[0]==path and r[2]==method for r in rules), method == 'HEAD', [r[3] for r in sorted(rules,key=lambda r:r[1]) if r[0]==path and r[2]==method][1:], not any(r[0]==path and r[2]==method for r in rules)]} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', [['/a', 3, 'GET', '/x'], ['/a', 1, 'GET', '/y']], '/a', 'GET'), {'request': '/requests/' + str(N) + '/0', 'decision': [['/x', '/y'], ['/x', '/y'], ['/y', '/x'], ['/x', '/y'], '/y', 2, 2, False, ['/x'], False]})
check('fixture 2', solve('/requests/' + str(N) + '/1', [['/a', 1, 'POST', '/p'], ['/a', 2, 'GET', '/g']], '/a', 'GET'), {'request': '/requests/' + str(N) + '/1', 'decision': [['/p', '/g'], ['/g'], ['/p', '/g'], ['/p', '/g'], '/g', 2, 1, False, [], False]})
check('fixture 3', solve('/requests/' + str(N) + '/2', [['/b', 1, 'GET', '/b'], ['/a', 1, 'GET', '/a']], '/a', 'GET'), {'request': '/requests/' + str(N) + '/2', 'decision': [['/a'], ['/b', '/a'], ['/b', '/a'], ['/b', '/a'], '/a', 2, 1, False, [], False]})
check('fixture 4', solve('/requests/' + str(N) + '/3', [['/a', 1, 'GET', '/x'], ['/a', 1, 'GET', '/y']], '/a', 'GET'), {'request': '/requests/' + str(N) + '/3', 'decision': [['/x', '/y'], ['/x', '/y'], ['/x', '/y'], ['/x', '/y'], '/x', 2, 2, False, ['/y'], False]})
check('fixture 5', solve('/requests/' + str(N) + '/4', [], '/a', 'GET'), {'request': '/requests/' + str(N) + '/4', 'decision': [[], [], [], [], None, 0, 0, False, [], True]})
check('fixture 6', solve('/requests/' + str(N) + '/5', [['/a', 1, 'HEAD', '/h'], ['/ab', 0, 'GET', '/q']], '/ab', 'HEAD'), {'request': '/requests/' + str(N) + '/5', 'decision': [['/q'], ['/h'], ['/q', '/h'], ['/h', '/q'], None, 2, 0, True, [], 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': [['/x', '/y'], ['/x', '/y'], ['/y', '/x'], ['/x', '/y'], '/y', 2, 2, False, ['/x'], False], 'request': '/requests/1/0'}{'decision': [['/x', '/y'], ['/x', '/y'], ['/y', '/x'], ['/x', '/y'], '/y', 2, 2, False, ['/x'], False], 'request': '/requests/1/0'}Passed
fixture 2{'decision': [['/p', '/g'], ['/g'], ['/p', '/g'], ['/p', '/g'], '/g', 2, 1, False, [], False], 'request': '/requests/1/1'}{'decision': [['/p', '/g'], ['/g'], ['/p', '/g'], ['/p', '/g'], '/g', 2, 1, False, [], False], 'request': '/requests/1/1'}Passed
fixture 3{'decision': [['/a'], ['/b', '/a'], ['/b', '/a'], ['/b', '/a'], '/a', 2, 1, False, [], False], 'request': '/requests/1/2'}{'decision': [['/a'], ['/b', '/a'], ['/b', '/a'], ['/b', '/a'], '/a', 2, 1, False, [], False], 'request': '/requests/1/2'}Passed
fixture 4{'decision': [['/x', '/y'], ['/x', '/y'], ['/x', '/y'], ['/x', '/y'], '/x', 2, 2, False, ['/y'], False], 'request': '/requests/1/3'}{'decision': [['/x', '/y'], ['/x', '/y'], ['/x', '/y'], ['/x', '/y'], '/x', 2, 2, False, ['/y'], False], 'request': '/requests/1/3'}Passed
fixture 5{'decision': [[], [], [], [], None, 0, 0, False, [], True], 'request': '/requests/1/4'}{'decision': [[], [], [], [], None, 0, 0, False, [], True], 'request': '/requests/1/4'}Passed
fixture 6{'decision': [['/q'], ['/q'], ['/q', '/h'], ['/h', '/q'], None, 2, 0, True, [], True], 'request': '/requests/1/5'}{'decision': [['/q'], ['/h'], ['/q', '/h'], ['/h', '/q'], None, 2, 0, True, [], True], 'request': '/requests/1/5'}Failed

SHA-256 / 487745b010598b23902e283050de8c94f4f196c33387923a2cbd3df4def1fa90

HELD IN THE MEMBER ARCHIVE

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This mechanism has 6 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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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 2026-09-29T14:41:34.797143+00:00.

Case digest / c9845ffd58a8d1076083bdaf7dabfe05bd4fb91dfb47b26cda10e9425002d5db