FA-27866 / HTTP redirects / Open access
Admit only actionable redirect responses: supported status set · case 01
A non-followable status is followed or See Other is omitted.
ROOT CAUSE
The supported-status-set decision uses '300 <= status < 400'; this violates the stipulated controller policy.
VERIFIED REPAIR
At this decision use 'status in (301,302,303,307,308)', preserving the other controller outputs.
Unsuccessful approach: The partial repair uses 'status in (301,302,307,308)' and still fails an explicit boundary or control.
Case contract
Admit only actionable redirect responses. 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, status, location, informational, tunnel, mode):
return {'request': request, 'decision': [300 <= status < 400, not informational, not tunnel, mode == 'manual', location == '']}
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', 300, '/a', False, False, 'follow'), {'request': '/requests/' + str(N) + '/0', 'decision': [False, True, True, False, False]})
check('fixture 2', solve('/requests/' + str(N) + '/1', 303, '/b', True, True, 'manual'), {'request': '/requests/' + str(N) + '/1', 'decision': [True, False, False, True, False]})
check('fixture 3', solve('/requests/' + str(N) + '/2', 307, '', False, False, 'error'), {'request': '/requests/' + str(N) + '/2', 'decision': [True, True, True, False, True]})
check('fixture 4', solve('/requests/' + str(N) + '/3', 304, None, False, True, 'follow'), {'request': '/requests/' + str(N) + '/3', 'decision': [False, True, False, False, False]})
check('fixture 5', solve('/requests/' + str(N) + '/4', 308, '/c', False, False, 'manual'), {'request': '/requests/' + str(N) + '/4', 'decision': [True, True, True, True, False]})
check('fixture 6', solve('/requests/' + str(N) + '/5', 200, '/d', False, False, 'follow'), {'request': '/requests/' + str(N) + '/5', 'decision': [False, True, True, False, 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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1 | {'decision': [True, True, True, False, False], 'request': '/requests/1/0'} | {'decision': [False, True, True, False, False], 'request': '/requests/1/0'} | Failed |
| fixture 2 | {'decision': [True, False, False, True, False], 'request': '/requests/1/1'} | {'decision': [True, False, False, True, False], 'request': '/requests/1/1'} | Passed |
| fixture 3 | {'decision': [True, True, True, False, True], 'request': '/requests/1/2'} | {'decision': [True, True, True, False, True], 'request': '/requests/1/2'} | Passed |
| fixture 4 | {'decision': [True, True, False, False, False], 'request': '/requests/1/3'} | {'decision': [False, True, False, False, False], 'request': '/requests/1/3'} | Failed |
| fixture 5 | {'decision': [True, True, True, True, False], 'request': '/requests/1/4'} | {'decision': [True, True, True, True, False], 'request': '/requests/1/4'} | Passed |
| fixture 6 | {'decision': [False, True, True, False, False], 'request': '/requests/1/5'} | {'decision': [False, True, True, False, False], 'request': '/requests/1/5'} | Passed |
SHA-256 / bb8d1d9255d4f3543367523ebe37760896ec4f4478f309c321311a8aabec219c
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, status, location, informational, tunnel, mode):
return {'request': request, 'decision': [status in (301,302,307,308), not informational, not tunnel, mode == 'manual', location == '']}
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', 300, '/a', False, False, 'follow'), {'request': '/requests/' + str(N) + '/0', 'decision': [False, True, True, False, False]})
check('fixture 2', solve('/requests/' + str(N) + '/1', 303, '/b', True, True, 'manual'), {'request': '/requests/' + str(N) + '/1', 'decision': [True, False, False, True, False]})
check('fixture 3', solve('/requests/' + str(N) + '/2', 307, '', False, False, 'error'), {'request': '/requests/' + str(N) + '/2', 'decision': [True, True, True, False, True]})
check('fixture 4', solve('/requests/' + str(N) + '/3', 304, None, False, True, 'follow'), {'request': '/requests/' + str(N) + '/3', 'decision': [False, True, False, False, False]})
check('fixture 5', solve('/requests/' + str(N) + '/4', 308, '/c', False, False, 'manual'), {'request': '/requests/' + str(N) + '/4', 'decision': [True, True, True, True, False]})
check('fixture 6', solve('/requests/' + str(N) + '/5', 200, '/d', False, False, 'follow'), {'request': '/requests/' + str(N) + '/5', 'decision': [False, True, True, False, 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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1 | {'decision': [False, True, True, False, False], 'request': '/requests/1/0'} | {'decision': [False, True, True, False, False], 'request': '/requests/1/0'} | Passed |
| fixture 2 | {'decision': [False, False, False, True, False], 'request': '/requests/1/1'} | {'decision': [True, False, False, True, False], 'request': '/requests/1/1'} | Failed |
| fixture 3 | {'decision': [True, True, True, False, True], 'request': '/requests/1/2'} | {'decision': [True, True, True, False, True], 'request': '/requests/1/2'} | Passed |
| fixture 4 | {'decision': [False, True, False, False, False], 'request': '/requests/1/3'} | {'decision': [False, True, False, False, False], 'request': '/requests/1/3'} | Passed |
| fixture 5 | {'decision': [True, True, True, True, False], 'request': '/requests/1/4'} | {'decision': [True, True, True, True, False], 'request': '/requests/1/4'} | Passed |
| fixture 6 | {'decision': [False, True, True, False, False], 'request': '/requests/1/5'} | {'decision': [False, True, True, False, False], 'request': '/requests/1/5'} | Passed |
SHA-256 / 98acd744b68bb819dea2c2d1dd5dae2e28dbac26febad6eaca4559ed6d5bbb1b
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, status, location, informational, tunnel, mode):
return {'request': request, 'decision': [status in (301,302,303,307,308), not informational, not tunnel, mode == 'manual', location == '']}
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', 300, '/a', False, False, 'follow'), {'request': '/requests/' + str(N) + '/0', 'decision': [False, True, True, False, False]})
check('fixture 2', solve('/requests/' + str(N) + '/1', 303, '/b', True, True, 'manual'), {'request': '/requests/' + str(N) + '/1', 'decision': [True, False, False, True, False]})
check('fixture 3', solve('/requests/' + str(N) + '/2', 307, '', False, False, 'error'), {'request': '/requests/' + str(N) + '/2', 'decision': [True, True, True, False, True]})
check('fixture 4', solve('/requests/' + str(N) + '/3', 304, None, False, True, 'follow'), {'request': '/requests/' + str(N) + '/3', 'decision': [False, True, False, False, False]})
check('fixture 5', solve('/requests/' + str(N) + '/4', 308, '/c', False, False, 'manual'), {'request': '/requests/' + str(N) + '/4', 'decision': [True, True, True, True, False]})
check('fixture 6', solve('/requests/' + str(N) + '/5', 200, '/d', False, False, 'follow'), {'request': '/requests/' + str(N) + '/5', 'decision': [False, True, True, False, 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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1 | {'decision': [False, True, True, False, False], 'request': '/requests/1/0'} | {'decision': [False, True, True, False, False], 'request': '/requests/1/0'} | Passed |
| fixture 2 | {'decision': [True, False, False, True, False], 'request': '/requests/1/1'} | {'decision': [True, False, False, True, False], 'request': '/requests/1/1'} | Passed |
| fixture 3 | {'decision': [True, True, True, False, True], 'request': '/requests/1/2'} | {'decision': [True, True, True, False, True], 'request': '/requests/1/2'} | Passed |
| fixture 4 | {'decision': [False, True, False, False, False], 'request': '/requests/1/3'} | {'decision': [False, True, False, False, False], 'request': '/requests/1/3'} | Passed |
| fixture 5 | {'decision': [True, True, True, True, False], 'request': '/requests/1/4'} | {'decision': [True, True, True, True, False], 'request': '/requests/1/4'} | Passed |
| fixture 6 | {'decision': [False, True, True, False, False], 'request': '/requests/1/5'} | {'decision': [False, True, True, False, False], 'request': '/requests/1/5'} | Passed |
SHA-256 / 6600a850f7d09737f6ce24d7f2dc287d11ab58b683794787629988cc7ba5f99d
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 2026-09-29T14:41:28.873228+00:00.
Case digest / 7e6b059a702e015850b118961ebe328662bdf84c65c37fe4bbad431e922e666f