FA-28076 / HTTP redirects / Open access
Preserve query-field structure while preparing a redirect target: first equals boundary · case 01
Preserve query-field structure while preparing a redirect target: the first equals boundary branch emits an incorrect decision.
ROOT CAUSE
The first-equals-boundary decision uses "[p.split('=')[-1] for p in query.split('&')] if query else []"; this violates the stipulated controller policy.
VERIFIED REPAIR
At this decision use "[p.partition('=')[2] for p in query.split('&')] if query else []", preserving the other controller outputs.
Unsuccessful approach: The partial repair uses "[p.split('=')[1] if '=' in p else '' for p in query.split('&')] if query else []" and still fails an explicit boundary or control.
Case contract
Preserve query-field structure while preparing a redirect target. 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, query):
return {'request': request, 'decision': [query.split('&') if query else [], [('bare' if '=' not in p else 'value') for p in query.split('&')] if query else [], [p.split('=')[-1] for p in query.split('&')] if query else [], query.count('&')+1 if query else 0, query.split('&') if query else []]}
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=1&a=1&b'), {'request': '/requests/' + str(N) + '/0', 'decision': [['a=1', 'a=1', 'b'], ['value', 'value', 'bare'], ['1', '1', ''], 3, ['a=1', 'a=1', 'b']]})
check('fixture 2', solve('/requests/' + str(N) + '/1', 'a=&b=x=y=z'), {'request': '/requests/' + str(N) + '/1', 'decision': [['a=', 'b=x=y=z'], ['value', 'value'], ['', 'x=y=z'], 2, ['a=', 'b=x=y=z']]})
check('fixture 3', solve('/requests/' + str(N) + '/2', 'a=x;y=z'), {'request': '/requests/' + str(N) + '/2', 'decision': [['a=x;y=z'], ['value'], ['x;y=z'], 1, ['a=x;y=z']]})
check('fixture 4', solve('/requests/' + str(N) + '/3', 'a=x%26b=y'), {'request': '/requests/' + str(N) + '/3', 'decision': [['a=x%26b=y'], ['value'], ['x%26b=y'], 1, ['a=x%26b=y']]})
check('fixture 5', solve('/requests/' + str(N) + '/4', 'flag'), {'request': '/requests/' + str(N) + '/4', 'decision': [['flag'], ['bare'], [''], 1, ['flag']]})
check('fixture 6', solve('/requests/' + str(N) + '/5', ''), {'request': '/requests/' + str(N) + '/5', 'decision': [[], [], [], 0, []]})
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': [['a=1', 'a=1', 'b'], ['value', 'value', 'bare'], ['1', '1', 'b'], 3, ['a=1', 'a=1', 'b']], 'request': '/requests/1/0'} | {'decision': [['a=1', 'a=1', 'b'], ['value', 'value', 'bare'], ['1', '1', ''], 3, ['a=1', 'a=1', 'b']], 'request': '/requests/1/0'} | Failed |
| fixture 2 | {'decision': [['a=', 'b=x=y=z'], ['value', 'value'], ['', 'z'], 2, ['a=', 'b=x=y=z']], 'request': '/requests/1/1'} | {'decision': [['a=', 'b=x=y=z'], ['value', 'value'], ['', 'x=y=z'], 2, ['a=', 'b=x=y=z']], 'request': '/requests/1/1'} | Failed |
| fixture 3 | {'decision': [['a=x;y=z'], ['value'], ['z'], 1, ['a=x;y=z']], 'request': '/requests/1/2'} | {'decision': [['a=x;y=z'], ['value'], ['x;y=z'], 1, ['a=x;y=z']], 'request': '/requests/1/2'} | Failed |
| fixture 4 | {'decision': [['a=x%26b=y'], ['value'], ['y'], 1, ['a=x%26b=y']], 'request': '/requests/1/3'} | {'decision': [['a=x%26b=y'], ['value'], ['x%26b=y'], 1, ['a=x%26b=y']], 'request': '/requests/1/3'} | Failed |
| fixture 5 | {'decision': [['flag'], ['bare'], ['flag'], 1, ['flag']], 'request': '/requests/1/4'} | {'decision': [['flag'], ['bare'], [''], 1, ['flag']], 'request': '/requests/1/4'} | Failed |
| fixture 6 | {'decision': [[], [], [], 0, []], 'request': '/requests/1/5'} | {'decision': [[], [], [], 0, []], 'request': '/requests/1/5'} | Passed |
SHA-256 / 7259216d8f1df0668dc38ec2e1b38addc28cb64941850e3673bfe19a87df5b52
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, query):
return {'request': request, 'decision': [query.split('&') if query else [], [('bare' if '=' not in p else 'value') for p in query.split('&')] if query else [], [p.split('=')[1] if '=' in p else '' for p in query.split('&')] if query else [], query.count('&')+1 if query else 0, query.split('&') if query else []]}
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=1&a=1&b'), {'request': '/requests/' + str(N) + '/0', 'decision': [['a=1', 'a=1', 'b'], ['value', 'value', 'bare'], ['1', '1', ''], 3, ['a=1', 'a=1', 'b']]})
check('fixture 2', solve('/requests/' + str(N) + '/1', 'a=&b=x=y=z'), {'request': '/requests/' + str(N) + '/1', 'decision': [['a=', 'b=x=y=z'], ['value', 'value'], ['', 'x=y=z'], 2, ['a=', 'b=x=y=z']]})
check('fixture 3', solve('/requests/' + str(N) + '/2', 'a=x;y=z'), {'request': '/requests/' + str(N) + '/2', 'decision': [['a=x;y=z'], ['value'], ['x;y=z'], 1, ['a=x;y=z']]})
check('fixture 4', solve('/requests/' + str(N) + '/3', 'a=x%26b=y'), {'request': '/requests/' + str(N) + '/3', 'decision': [['a=x%26b=y'], ['value'], ['x%26b=y'], 1, ['a=x%26b=y']]})
check('fixture 5', solve('/requests/' + str(N) + '/4', 'flag'), {'request': '/requests/' + str(N) + '/4', 'decision': [['flag'], ['bare'], [''], 1, ['flag']]})
check('fixture 6', solve('/requests/' + str(N) + '/5', ''), {'request': '/requests/' + str(N) + '/5', 'decision': [[], [], [], 0, []]})
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': [['a=1', 'a=1', 'b'], ['value', 'value', 'bare'], ['1', '1', ''], 3, ['a=1', 'a=1', 'b']], 'request': '/requests/1/0'} | {'decision': [['a=1', 'a=1', 'b'], ['value', 'value', 'bare'], ['1', '1', ''], 3, ['a=1', 'a=1', 'b']], 'request': '/requests/1/0'} | Passed |
| fixture 2 | {'decision': [['a=', 'b=x=y=z'], ['value', 'value'], ['', 'x'], 2, ['a=', 'b=x=y=z']], 'request': '/requests/1/1'} | {'decision': [['a=', 'b=x=y=z'], ['value', 'value'], ['', 'x=y=z'], 2, ['a=', 'b=x=y=z']], 'request': '/requests/1/1'} | Failed |
| fixture 3 | {'decision': [['a=x;y=z'], ['value'], ['x;y'], 1, ['a=x;y=z']], 'request': '/requests/1/2'} | {'decision': [['a=x;y=z'], ['value'], ['x;y=z'], 1, ['a=x;y=z']], 'request': '/requests/1/2'} | Failed |
| fixture 4 | {'decision': [['a=x%26b=y'], ['value'], ['x%26b'], 1, ['a=x%26b=y']], 'request': '/requests/1/3'} | {'decision': [['a=x%26b=y'], ['value'], ['x%26b=y'], 1, ['a=x%26b=y']], 'request': '/requests/1/3'} | Failed |
| fixture 5 | {'decision': [['flag'], ['bare'], [''], 1, ['flag']], 'request': '/requests/1/4'} | {'decision': [['flag'], ['bare'], [''], 1, ['flag']], 'request': '/requests/1/4'} | Passed |
| fixture 6 | {'decision': [[], [], [], 0, []], 'request': '/requests/1/5'} | {'decision': [[], [], [], 0, []], 'request': '/requests/1/5'} | Passed |
SHA-256 / 5833b353b77f5c684278c42005943b696a41b897133a86a64892fd9a6cbf1785
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, query):
return {'request': request, 'decision': [query.split('&') if query else [], [('bare' if '=' not in p else 'value') for p in query.split('&')] if query else [], [p.partition('=')[2] for p in query.split('&')] if query else [], query.count('&')+1 if query else 0, query.split('&') if query else []]}
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=1&a=1&b'), {'request': '/requests/' + str(N) + '/0', 'decision': [['a=1', 'a=1', 'b'], ['value', 'value', 'bare'], ['1', '1', ''], 3, ['a=1', 'a=1', 'b']]})
check('fixture 2', solve('/requests/' + str(N) + '/1', 'a=&b=x=y=z'), {'request': '/requests/' + str(N) + '/1', 'decision': [['a=', 'b=x=y=z'], ['value', 'value'], ['', 'x=y=z'], 2, ['a=', 'b=x=y=z']]})
check('fixture 3', solve('/requests/' + str(N) + '/2', 'a=x;y=z'), {'request': '/requests/' + str(N) + '/2', 'decision': [['a=x;y=z'], ['value'], ['x;y=z'], 1, ['a=x;y=z']]})
check('fixture 4', solve('/requests/' + str(N) + '/3', 'a=x%26b=y'), {'request': '/requests/' + str(N) + '/3', 'decision': [['a=x%26b=y'], ['value'], ['x%26b=y'], 1, ['a=x%26b=y']]})
check('fixture 5', solve('/requests/' + str(N) + '/4', 'flag'), {'request': '/requests/' + str(N) + '/4', 'decision': [['flag'], ['bare'], [''], 1, ['flag']]})
check('fixture 6', solve('/requests/' + str(N) + '/5', ''), {'request': '/requests/' + str(N) + '/5', 'decision': [[], [], [], 0, []]})
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': [['a=1', 'a=1', 'b'], ['value', 'value', 'bare'], ['1', '1', ''], 3, ['a=1', 'a=1', 'b']], 'request': '/requests/1/0'} | {'decision': [['a=1', 'a=1', 'b'], ['value', 'value', 'bare'], ['1', '1', ''], 3, ['a=1', 'a=1', 'b']], 'request': '/requests/1/0'} | Passed |
| fixture 2 | {'decision': [['a=', 'b=x=y=z'], ['value', 'value'], ['', 'x=y=z'], 2, ['a=', 'b=x=y=z']], 'request': '/requests/1/1'} | {'decision': [['a=', 'b=x=y=z'], ['value', 'value'], ['', 'x=y=z'], 2, ['a=', 'b=x=y=z']], 'request': '/requests/1/1'} | Passed |
| fixture 3 | {'decision': [['a=x;y=z'], ['value'], ['x;y=z'], 1, ['a=x;y=z']], 'request': '/requests/1/2'} | {'decision': [['a=x;y=z'], ['value'], ['x;y=z'], 1, ['a=x;y=z']], 'request': '/requests/1/2'} | Passed |
| fixture 4 | {'decision': [['a=x%26b=y'], ['value'], ['x%26b=y'], 1, ['a=x%26b=y']], 'request': '/requests/1/3'} | {'decision': [['a=x%26b=y'], ['value'], ['x%26b=y'], 1, ['a=x%26b=y']], 'request': '/requests/1/3'} | Passed |
| fixture 5 | {'decision': [['flag'], ['bare'], [''], 1, ['flag']], 'request': '/requests/1/4'} | {'decision': [['flag'], ['bare'], [''], 1, ['flag']], 'request': '/requests/1/4'} | Passed |
| fixture 6 | {'decision': [[], [], [], 0, []], 'request': '/requests/1/5'} | {'decision': [[], [], [], 0, []], 'request': '/requests/1/5'} | Passed |
SHA-256 / 150480b926365e5f982776604ea2dc42a580250138d66f4926e52249023c9615
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 2026-09-29T14:41:30.729057+00:00.
Case digest / c90e3ecb80b1c57be701b3bd92b6423d0bfef9501e7ef1c7ec3080b8a4364209