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FA-28306 / HTTP redirects / Open access

Expose final response metadata without leaking intermediate representation state: final body only · case 01

Expose final response metadata without leaking intermediate representation state: the final body only branch emits an incorrect decision.

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

ROOT CAUSE

The final-body-only decision uses "'' if len(statuses)>1 else body"; this violates the stipulated controller policy.

VERIFIED REPAIR

At this decision use 'body', preserving the other controller outputs.

Unsuccessful approach: The partial repair uses "body if statuses[-1] == 200 else ''" and still fails an explicit boundary or control.

Case contract

Expose final response metadata without leaking intermediate representation state. 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, original, final, statuses, body, intermediate_lengths, final_length):
    return {'request': request, 'decision': [final, statuses[-1], len(statuses)>1, '' if len(statuses)>1 else body, final_length, sum(intermediate_lengths)+final_length, statuses[:-1], len(statuses)-1, statuses[-1]>=400, statuses[0]]} 
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', '/c', [301, 302, 200], 'ok', [8, 9], 2), {'request': '/requests/' + str(N) + '/0', 'decision': ['/c', 200, True, 'ok', 2, 19, [301, 302], 2, False, 301]})
check('fixture 2', solve('/requests/' + str(N) + '/1', '/a', '/a', [200], '', [], 0), {'request': '/requests/' + str(N) + '/1', 'decision': ['/a', 200, False, '', 0, 0, [], 0, False, 200]})
check('fixture 3', solve('/requests/' + str(N) + '/2', '/x', '/y', [307, 404], 'err', [100], 3), {'request': '/requests/' + str(N) + '/2', 'decision': ['/y', 404, True, 'err', 3, 103, [307], 1, True, 307]})
check('fixture 4', solve('/requests/' + str(N) + '/3', '/x', '/x', [302, 302, 200], 'done', [0, 2], 4), {'request': '/requests/' + str(N) + '/3', 'decision': ['/x', 200, True, 'done', 4, 6, [302, 302], 2, False, 302]})
check('fixture 5', solve('/requests/' + str(N) + '/4', '/m', '/n', [308, 204], '', [5], 0), {'request': '/requests/' + str(N) + '/4', 'decision': ['/n', 204, True, '', 0, 5, [308], 1, False, 308]})
check('fixture 6', solve('/requests/' + str(N) + '/5', '/v', '/w', [303, 500], 'bad', [7], 3), {'request': '/requests/' + str(N) + '/5', 'decision': ['/w', 500, True, 'bad', 3, 10, [303], 1, True, 303]})
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': ['/c', 200, True, '', 2, 19, [301, 302], 2, False, 301], 'request': '/requests/1/0'}{'decision': ['/c', 200, True, 'ok', 2, 19, [301, 302], 2, False, 301], 'request': '/requests/1/0'}Failed
fixture 2{'decision': ['/a', 200, False, '', 0, 0, [], 0, False, 200], 'request': '/requests/1/1'}{'decision': ['/a', 200, False, '', 0, 0, [], 0, False, 200], 'request': '/requests/1/1'}Passed
fixture 3{'decision': ['/y', 404, True, '', 3, 103, [307], 1, True, 307], 'request': '/requests/1/2'}{'decision': ['/y', 404, True, 'err', 3, 103, [307], 1, True, 307], 'request': '/requests/1/2'}Failed
fixture 4{'decision': ['/x', 200, True, '', 4, 6, [302, 302], 2, False, 302], 'request': '/requests/1/3'}{'decision': ['/x', 200, True, 'done', 4, 6, [302, 302], 2, False, 302], 'request': '/requests/1/3'}Failed
fixture 5{'decision': ['/n', 204, True, '', 0, 5, [308], 1, False, 308], 'request': '/requests/1/4'}{'decision': ['/n', 204, True, '', 0, 5, [308], 1, False, 308], 'request': '/requests/1/4'}Passed
fixture 6{'decision': ['/w', 500, True, '', 3, 10, [303], 1, True, 303], 'request': '/requests/1/5'}{'decision': ['/w', 500, True, 'bad', 3, 10, [303], 1, True, 303], 'request': '/requests/1/5'}Failed

SHA-256 / 1ce2a4d91c7348ffef5c6ed7cbb7a303fd97d666cd4a69d8078f911a7cbac065

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, original, final, statuses, body, intermediate_lengths, final_length):
    return {'request': request, 'decision': [final, statuses[-1], len(statuses)>1, body if statuses[-1] == 200 else '', final_length, sum(intermediate_lengths)+final_length, statuses[:-1], len(statuses)-1, statuses[-1]>=400, statuses[0]]} 
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', '/c', [301, 302, 200], 'ok', [8, 9], 2), {'request': '/requests/' + str(N) + '/0', 'decision': ['/c', 200, True, 'ok', 2, 19, [301, 302], 2, False, 301]})
check('fixture 2', solve('/requests/' + str(N) + '/1', '/a', '/a', [200], '', [], 0), {'request': '/requests/' + str(N) + '/1', 'decision': ['/a', 200, False, '', 0, 0, [], 0, False, 200]})
check('fixture 3', solve('/requests/' + str(N) + '/2', '/x', '/y', [307, 404], 'err', [100], 3), {'request': '/requests/' + str(N) + '/2', 'decision': ['/y', 404, True, 'err', 3, 103, [307], 1, True, 307]})
check('fixture 4', solve('/requests/' + str(N) + '/3', '/x', '/x', [302, 302, 200], 'done', [0, 2], 4), {'request': '/requests/' + str(N) + '/3', 'decision': ['/x', 200, True, 'done', 4, 6, [302, 302], 2, False, 302]})
check('fixture 5', solve('/requests/' + str(N) + '/4', '/m', '/n', [308, 204], '', [5], 0), {'request': '/requests/' + str(N) + '/4', 'decision': ['/n', 204, True, '', 0, 5, [308], 1, False, 308]})
check('fixture 6', solve('/requests/' + str(N) + '/5', '/v', '/w', [303, 500], 'bad', [7], 3), {'request': '/requests/' + str(N) + '/5', 'decision': ['/w', 500, True, 'bad', 3, 10, [303], 1, True, 303]})
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': ['/c', 200, True, 'ok', 2, 19, [301, 302], 2, False, 301], 'request': '/requests/1/0'}{'decision': ['/c', 200, True, 'ok', 2, 19, [301, 302], 2, False, 301], 'request': '/requests/1/0'}Passed
fixture 2{'decision': ['/a', 200, False, '', 0, 0, [], 0, False, 200], 'request': '/requests/1/1'}{'decision': ['/a', 200, False, '', 0, 0, [], 0, False, 200], 'request': '/requests/1/1'}Passed
fixture 3{'decision': ['/y', 404, True, '', 3, 103, [307], 1, True, 307], 'request': '/requests/1/2'}{'decision': ['/y', 404, True, 'err', 3, 103, [307], 1, True, 307], 'request': '/requests/1/2'}Failed
fixture 4{'decision': ['/x', 200, True, 'done', 4, 6, [302, 302], 2, False, 302], 'request': '/requests/1/3'}{'decision': ['/x', 200, True, 'done', 4, 6, [302, 302], 2, False, 302], 'request': '/requests/1/3'}Passed
fixture 5{'decision': ['/n', 204, True, '', 0, 5, [308], 1, False, 308], 'request': '/requests/1/4'}{'decision': ['/n', 204, True, '', 0, 5, [308], 1, False, 308], 'request': '/requests/1/4'}Passed
fixture 6{'decision': ['/w', 500, True, '', 3, 10, [303], 1, True, 303], 'request': '/requests/1/5'}{'decision': ['/w', 500, True, 'bad', 3, 10, [303], 1, True, 303], 'request': '/requests/1/5'}Failed

SHA-256 / f9b74556de092356a798e5ddc82f97e2442bd841ed58958d34b5239eb8deffe4

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, original, final, statuses, body, intermediate_lengths, final_length):
    return {'request': request, 'decision': [final, statuses[-1], len(statuses)>1, body, final_length, sum(intermediate_lengths)+final_length, statuses[:-1], len(statuses)-1, statuses[-1]>=400, statuses[0]]} 
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', '/c', [301, 302, 200], 'ok', [8, 9], 2), {'request': '/requests/' + str(N) + '/0', 'decision': ['/c', 200, True, 'ok', 2, 19, [301, 302], 2, False, 301]})
check('fixture 2', solve('/requests/' + str(N) + '/1', '/a', '/a', [200], '', [], 0), {'request': '/requests/' + str(N) + '/1', 'decision': ['/a', 200, False, '', 0, 0, [], 0, False, 200]})
check('fixture 3', solve('/requests/' + str(N) + '/2', '/x', '/y', [307, 404], 'err', [100], 3), {'request': '/requests/' + str(N) + '/2', 'decision': ['/y', 404, True, 'err', 3, 103, [307], 1, True, 307]})
check('fixture 4', solve('/requests/' + str(N) + '/3', '/x', '/x', [302, 302, 200], 'done', [0, 2], 4), {'request': '/requests/' + str(N) + '/3', 'decision': ['/x', 200, True, 'done', 4, 6, [302, 302], 2, False, 302]})
check('fixture 5', solve('/requests/' + str(N) + '/4', '/m', '/n', [308, 204], '', [5], 0), {'request': '/requests/' + str(N) + '/4', 'decision': ['/n', 204, True, '', 0, 5, [308], 1, False, 308]})
check('fixture 6', solve('/requests/' + str(N) + '/5', '/v', '/w', [303, 500], 'bad', [7], 3), {'request': '/requests/' + str(N) + '/5', 'decision': ['/w', 500, True, 'bad', 3, 10, [303], 1, True, 303]})
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': ['/c', 200, True, 'ok', 2, 19, [301, 302], 2, False, 301], 'request': '/requests/1/0'}{'decision': ['/c', 200, True, 'ok', 2, 19, [301, 302], 2, False, 301], 'request': '/requests/1/0'}Passed
fixture 2{'decision': ['/a', 200, False, '', 0, 0, [], 0, False, 200], 'request': '/requests/1/1'}{'decision': ['/a', 200, False, '', 0, 0, [], 0, False, 200], 'request': '/requests/1/1'}Passed
fixture 3{'decision': ['/y', 404, True, 'err', 3, 103, [307], 1, True, 307], 'request': '/requests/1/2'}{'decision': ['/y', 404, True, 'err', 3, 103, [307], 1, True, 307], 'request': '/requests/1/2'}Passed
fixture 4{'decision': ['/x', 200, True, 'done', 4, 6, [302, 302], 2, False, 302], 'request': '/requests/1/3'}{'decision': ['/x', 200, True, 'done', 4, 6, [302, 302], 2, False, 302], 'request': '/requests/1/3'}Passed
fixture 5{'decision': ['/n', 204, True, '', 0, 5, [308], 1, False, 308], 'request': '/requests/1/4'}{'decision': ['/n', 204, True, '', 0, 5, [308], 1, False, 308], 'request': '/requests/1/4'}Passed
fixture 6{'decision': ['/w', 500, True, 'bad', 3, 10, [303], 1, True, 303], 'request': '/requests/1/5'}{'decision': ['/w', 500, True, 'bad', 3, 10, [303], 1, True, 303], 'request': '/requests/1/5'}Passed

SHA-256 / 0e41b750c86286acb11e49bcf252a2b14876a150194c4eeabeb4f43881e20210

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 2026-09-29T14:41:32.698577+00:00.

Case digest / 09886e74fb830ac434b25c5551130b14603a32ee8ede0506da87a83cf3ecc782