FA-28626 / HTTP redirects / Open access
Translate a redirect between internal and public application mounts: public prefix join · case 01
Translate a redirect between internal and public application mounts: the public prefix join branch emits an incorrect decision.
ROOT CAUSE
The public-prefix-join decision uses 'external + path'; this violates the stipulated controller policy.
THE FAILURE
The public-prefix-join decision uses 'external + path'; this violates the stipulated controller policy.
Unsuccessful approach: The partial repair uses "external + '/' + path" and still fails an explicit boundary or control.
Case contract
Translate a redirect between internal and public application mounts. 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, internal, external, query, trailing, absolute):
return {'request': request, 'decision': [path == internal or path.startswith(internal.rstrip('/')+'/'), path[len(internal):] if path == internal or path.startswith(internal.rstrip('/')+'/') else path, external or '/', ('?' + query) if query else '', path+'/' if trailing and not path.endswith('/') else path, 'absolute' if absolute else 'relative', path[1:] if internal == '/' else path, external + path, ('/' + external.lstrip('/')) if external else '/', path.startswith(internal.rstrip('/')+'/') or path == internal]}
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', '/app/a', '/app', '/public', 'x=1', False, False), {'request': '/requests/' + str(N) + '/0', 'decision': [True, '/a', '/public', '?x=1', '/app/a', 'relative', '/app/a', '/public/app/a', '/public', True]})
check('fixture 2', solve('/requests/' + str(N) + '/1', '/apple/a', '/app', '/public', '', False, False), {'request': '/requests/' + str(N) + '/1', 'decision': [False, '/apple/a', '/public', '', '/apple/a', 'relative', '/apple/a', '/public/apple/a', '/public', False]})
check('fixture 3', solve('/requests/' + str(N) + '/2', '/app', '/app', '/public', 'q=', True, False), {'request': '/requests/' + str(N) + '/2', 'decision': [True, '', '/public', '?q=', '/app/', 'relative', '/app', '/public/app', '/public', True]})
check('fixture 4', solve('/requests/' + str(N) + '/3', '/app/a/app', '/app', '/v2', 'k=1&k=2', True, True), {'request': '/requests/' + str(N) + '/3', 'decision': [True, '/a/app', '/v2', '?k=1&k=2', '/app/a/app/', 'absolute', '/app/a/app', '/v2/app/a/app', '/v2', True]})
check('fixture 5', solve('/requests/' + str(N) + '/4', '/', '/', '/edge', '', False, True), {'request': '/requests/' + str(N) + '/4', 'decision': [True, '', '/edge', '', '/', 'absolute', '', '/edge/', '/edge', True]})
check('fixture 6', solve('/requests/' + str(N) + '/5', '/app/a', '/app', '', 'x=2', False, True), {'request': '/requests/' + str(N) + '/5', 'decision': [True, '/a', '/', '?x=2', '/app/a', 'absolute', '/app/a', '/app/a', '/', True]})
check('fixture 7', solve('/requests/' + str(N) + '/6', '/app/a/', '/app', '/public/', '', True, False), {'request': '/requests/' + str(N) + '/6', 'decision': [True, '/a/', '/public/', '', '/app/a/', 'relative', '/app/a/', '/public/app/a/', '/public/', 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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1 | {'decision': [True, '/a', '/public', '?x=1', '/app/a', 'relative', '/app/a', '/public/app/a', '/public', True], 'request': '/requests/1/0'} | {'decision': [True, '/a', '/public', '?x=1', '/app/a', 'relative', '/app/a', '/public/app/a', '/public', True], 'request': '/requests/1/0'} | Passed |
| fixture 2 | {'decision': [False, '/apple/a', '/public', '', '/apple/a', 'relative', '/apple/a', '/public/apple/a', '/public', False], 'request': '/requests/1/1'} | {'decision': [False, '/apple/a', '/public', '', '/apple/a', 'relative', '/apple/a', '/public/apple/a', '/public', False], 'request': '/requests/1/1'} | Passed |
| fixture 3 | {'decision': [True, '', '/public', '?q=', '/app/', 'relative', '/app', '/public/app', '/public', True], 'request': '/requests/1/2'} | {'decision': [True, '', '/public', '?q=', '/app/', 'relative', '/app', '/public/app', '/public', True], 'request': '/requests/1/2'} | Passed |
| fixture 4 | {'decision': [True, '/a/app', '/v2', '?k=1&k=2', '/app/a/app/', 'absolute', '/app/a/app', '/v2/app/a/app', '/v2', True], 'request': '/requests/1/3'} | {'decision': [True, '/a/app', '/v2', '?k=1&k=2', '/app/a/app/', 'absolute', '/app/a/app', '/v2/app/a/app', '/v2', True], 'request': '/requests/1/3'} | Passed |
| fixture 5 | {'decision': [True, '', '/edge', '', '/', 'absolute', '', '/edge/', '/edge', True], 'request': '/requests/1/4'} | {'decision': [True, '', '/edge', '', '/', 'absolute', '', '/edge/', '/edge', True], 'request': '/requests/1/4'} | Passed |
| fixture 6 | {'decision': [True, '/a', '/', '?x=2', '/app/a', 'absolute', '/app/a', '/app/a', '/', True], 'request': '/requests/1/5'} | {'decision': [True, '/a', '/', '?x=2', '/app/a', 'absolute', '/app/a', '/app/a', '/', True], 'request': '/requests/1/5'} | Passed |
| fixture 7 | {'decision': [True, '/a/', '/public/', '', '/app/a/', 'relative', '/app/a/', '/public//app/a/', '/public/', True], 'request': '/requests/1/6'} | {'decision': [True, '/a/', '/public/', '', '/app/a/', 'relative', '/app/a/', '/public/app/a/', '/public/', True], 'request': '/requests/1/6'} | Failed |
SHA-256 / 3d92f4033c4a7e56e9c8cec2d45ce6b6e3566ca3668f4abd4cc75d0f3c86c16b
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, internal, external, query, trailing, absolute):
return {'request': request, 'decision': [path == internal or path.startswith(internal.rstrip('/')+'/'), path[len(internal):] if path == internal or path.startswith(internal.rstrip('/')+'/') else path, external or '/', ('?' + query) if query else '', path+'/' if trailing and not path.endswith('/') else path, 'absolute' if absolute else 'relative', path[1:] if internal == '/' else path, external + '/' + path, ('/' + external.lstrip('/')) if external else '/', path.startswith(internal.rstrip('/')+'/') or path == internal]}
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', '/app/a', '/app', '/public', 'x=1', False, False), {'request': '/requests/' + str(N) + '/0', 'decision': [True, '/a', '/public', '?x=1', '/app/a', 'relative', '/app/a', '/public/app/a', '/public', True]})
check('fixture 2', solve('/requests/' + str(N) + '/1', '/apple/a', '/app', '/public', '', False, False), {'request': '/requests/' + str(N) + '/1', 'decision': [False, '/apple/a', '/public', '', '/apple/a', 'relative', '/apple/a', '/public/apple/a', '/public', False]})
check('fixture 3', solve('/requests/' + str(N) + '/2', '/app', '/app', '/public', 'q=', True, False), {'request': '/requests/' + str(N) + '/2', 'decision': [True, '', '/public', '?q=', '/app/', 'relative', '/app', '/public/app', '/public', True]})
check('fixture 4', solve('/requests/' + str(N) + '/3', '/app/a/app', '/app', '/v2', 'k=1&k=2', True, True), {'request': '/requests/' + str(N) + '/3', 'decision': [True, '/a/app', '/v2', '?k=1&k=2', '/app/a/app/', 'absolute', '/app/a/app', '/v2/app/a/app', '/v2', True]})
check('fixture 5', solve('/requests/' + str(N) + '/4', '/', '/', '/edge', '', False, True), {'request': '/requests/' + str(N) + '/4', 'decision': [True, '', '/edge', '', '/', 'absolute', '', '/edge/', '/edge', True]})
check('fixture 6', solve('/requests/' + str(N) + '/5', '/app/a', '/app', '', 'x=2', False, True), {'request': '/requests/' + str(N) + '/5', 'decision': [True, '/a', '/', '?x=2', '/app/a', 'absolute', '/app/a', '/app/a', '/', True]})
check('fixture 7', solve('/requests/' + str(N) + '/6', '/app/a/', '/app', '/public/', '', True, False), {'request': '/requests/' + str(N) + '/6', 'decision': [True, '/a/', '/public/', '', '/app/a/', 'relative', '/app/a/', '/public/app/a/', '/public/', 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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1 | {'decision': [True, '/a', '/public', '?x=1', '/app/a', 'relative', '/app/a', '/public//app/a', '/public', True], 'request': '/requests/1/0'} | {'decision': [True, '/a', '/public', '?x=1', '/app/a', 'relative', '/app/a', '/public/app/a', '/public', True], 'request': '/requests/1/0'} | Failed |
| fixture 2 | {'decision': [False, '/apple/a', '/public', '', '/apple/a', 'relative', '/apple/a', '/public//apple/a', '/public', False], 'request': '/requests/1/1'} | {'decision': [False, '/apple/a', '/public', '', '/apple/a', 'relative', '/apple/a', '/public/apple/a', '/public', False], 'request': '/requests/1/1'} | Failed |
| fixture 3 | {'decision': [True, '', '/public', '?q=', '/app/', 'relative', '/app', '/public//app', '/public', True], 'request': '/requests/1/2'} | {'decision': [True, '', '/public', '?q=', '/app/', 'relative', '/app', '/public/app', '/public', True], 'request': '/requests/1/2'} | Failed |
| fixture 4 | {'decision': [True, '/a/app', '/v2', '?k=1&k=2', '/app/a/app/', 'absolute', '/app/a/app', '/v2//app/a/app', '/v2', True], 'request': '/requests/1/3'} | {'decision': [True, '/a/app', '/v2', '?k=1&k=2', '/app/a/app/', 'absolute', '/app/a/app', '/v2/app/a/app', '/v2', True], 'request': '/requests/1/3'} | Failed |
| fixture 5 | {'decision': [True, '', '/edge', '', '/', 'absolute', '', '/edge//', '/edge', True], 'request': '/requests/1/4'} | {'decision': [True, '', '/edge', '', '/', 'absolute', '', '/edge/', '/edge', True], 'request': '/requests/1/4'} | Failed |
| fixture 6 | {'decision': [True, '/a', '/', '?x=2', '/app/a', 'absolute', '/app/a', '//app/a', '/', True], 'request': '/requests/1/5'} | {'decision': [True, '/a', '/', '?x=2', '/app/a', 'absolute', '/app/a', '/app/a', '/', True], 'request': '/requests/1/5'} | Failed |
| fixture 7 | {'decision': [True, '/a/', '/public/', '', '/app/a/', 'relative', '/app/a/', '/public///app/a/', '/public/', True], 'request': '/requests/1/6'} | {'decision': [True, '/a/', '/public/', '', '/app/a/', 'relative', '/app/a/', '/public/app/a/', '/public/', True], 'request': '/requests/1/6'} | Failed |
SHA-256 / e8620f14456bb9aad62e8d7c8110726f12430371567199dceb827791696d6bcf
HELD IN THE MEMBER ARCHIVE
The verified repair and its recorded checks are member-only.
This mechanism has 7 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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Sign in to the archive ↗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 2026-09-29T14:41:35.697873+00:00.
Case digest / 0c5b0081a300dd8a97588b686c35d9e70b94b7ececc613e0d935ed068f197e8f