FA-28131 / HTTP redirects / Open access
Expose redirect events in request order without false completion: last observed target · case 01
Expose redirect events in request order without false completion: the last observed target branch emits an incorrect decision.
ROOT CAUSE
The last-observed-target decision uses 'events[0] if events else None'; this violates the stipulated controller policy.
VERIFIED REPAIR
At this decision use 'events[-1] if events else None', preserving the other controller outputs.
Unsuccessful approach: The partial repair uses 'target' and still fails an explicit boundary or control.
Case contract
Expose redirect events in request order without false completion. 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, events, accepted, target, done, canceled):
return {'request': request, 'decision': [events + ([target] if accepted else []), done and not canceled, len(events), events[0] if events else None, 'canceled' if canceled else ('redirect' if accepted else 'blocked')]}
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', '/b', '/a'], False, '/c', True, True), {'request': '/requests/' + str(N) + '/0', 'decision': [['/a', '/b', '/a'], False, 3, '/a', 'canceled']})
check('fixture 2', solve('/requests/' + str(N) + '/1', ['/a', '/b'], True, '/c', False, False), {'request': '/requests/' + str(N) + '/1', 'decision': [['/a', '/b', '/c'], False, 2, '/b', 'redirect']})
check('fixture 3', solve('/requests/' + str(N) + '/2', [], False, '/a', True, False), {'request': '/requests/' + str(N) + '/2', 'decision': [[], True, 0, None, 'blocked']})
check('fixture 4', solve('/requests/' + str(N) + '/3', [], True, '/a', False, False), {'request': '/requests/' + str(N) + '/3', 'decision': [['/a'], False, 0, None, 'redirect']})
check('fixture 5', solve('/requests/' + str(N) + '/4', ['/b'], True, '/c', True, True), {'request': '/requests/' + str(N) + '/4', 'decision': [['/b', '/c'], False, 1, '/b', 'canceled']})
check('fixture 6', solve('/requests/' + str(N) + '/5', ['/a', '/b'], False, '/c', False, False), {'request': '/requests/' + str(N) + '/5', 'decision': [['/a', '/b'], False, 2, '/b', 'blocked']})
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', '/b', '/a'], False, 3, '/a', 'canceled'], 'request': '/requests/1/0'} | {'decision': [['/a', '/b', '/a'], False, 3, '/a', 'canceled'], 'request': '/requests/1/0'} | Passed |
| fixture 2 | {'decision': [['/a', '/b', '/c'], False, 2, '/a', 'redirect'], 'request': '/requests/1/1'} | {'decision': [['/a', '/b', '/c'], False, 2, '/b', 'redirect'], 'request': '/requests/1/1'} | Failed |
| fixture 3 | {'decision': [[], True, 0, None, 'blocked'], 'request': '/requests/1/2'} | {'decision': [[], True, 0, None, 'blocked'], 'request': '/requests/1/2'} | Passed |
| fixture 4 | {'decision': [['/a'], False, 0, None, 'redirect'], 'request': '/requests/1/3'} | {'decision': [['/a'], False, 0, None, 'redirect'], 'request': '/requests/1/3'} | Passed |
| fixture 5 | {'decision': [['/b', '/c'], False, 1, '/b', 'canceled'], 'request': '/requests/1/4'} | {'decision': [['/b', '/c'], False, 1, '/b', 'canceled'], 'request': '/requests/1/4'} | Passed |
| fixture 6 | {'decision': [['/a', '/b'], False, 2, '/a', 'blocked'], 'request': '/requests/1/5'} | {'decision': [['/a', '/b'], False, 2, '/b', 'blocked'], 'request': '/requests/1/5'} | Failed |
SHA-256 / 84ee8110e2c80dd90fc77e5b23f77689dee2e9d587870fe656cd6e3b999dd436
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, events, accepted, target, done, canceled):
return {'request': request, 'decision': [events + ([target] if accepted else []), done and not canceled, len(events), target, 'canceled' if canceled else ('redirect' if accepted else 'blocked')]}
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', '/b', '/a'], False, '/c', True, True), {'request': '/requests/' + str(N) + '/0', 'decision': [['/a', '/b', '/a'], False, 3, '/a', 'canceled']})
check('fixture 2', solve('/requests/' + str(N) + '/1', ['/a', '/b'], True, '/c', False, False), {'request': '/requests/' + str(N) + '/1', 'decision': [['/a', '/b', '/c'], False, 2, '/b', 'redirect']})
check('fixture 3', solve('/requests/' + str(N) + '/2', [], False, '/a', True, False), {'request': '/requests/' + str(N) + '/2', 'decision': [[], True, 0, None, 'blocked']})
check('fixture 4', solve('/requests/' + str(N) + '/3', [], True, '/a', False, False), {'request': '/requests/' + str(N) + '/3', 'decision': [['/a'], False, 0, None, 'redirect']})
check('fixture 5', solve('/requests/' + str(N) + '/4', ['/b'], True, '/c', True, True), {'request': '/requests/' + str(N) + '/4', 'decision': [['/b', '/c'], False, 1, '/b', 'canceled']})
check('fixture 6', solve('/requests/' + str(N) + '/5', ['/a', '/b'], False, '/c', False, False), {'request': '/requests/' + str(N) + '/5', 'decision': [['/a', '/b'], False, 2, '/b', 'blocked']})
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', '/b', '/a'], False, 3, '/c', 'canceled'], 'request': '/requests/1/0'} | {'decision': [['/a', '/b', '/a'], False, 3, '/a', 'canceled'], 'request': '/requests/1/0'} | Failed |
| fixture 2 | {'decision': [['/a', '/b', '/c'], False, 2, '/c', 'redirect'], 'request': '/requests/1/1'} | {'decision': [['/a', '/b', '/c'], False, 2, '/b', 'redirect'], 'request': '/requests/1/1'} | Failed |
| fixture 3 | {'decision': [[], True, 0, '/a', 'blocked'], 'request': '/requests/1/2'} | {'decision': [[], True, 0, None, 'blocked'], 'request': '/requests/1/2'} | Failed |
| fixture 4 | {'decision': [['/a'], False, 0, '/a', 'redirect'], 'request': '/requests/1/3'} | {'decision': [['/a'], False, 0, None, 'redirect'], 'request': '/requests/1/3'} | Failed |
| fixture 5 | {'decision': [['/b', '/c'], False, 1, '/c', 'canceled'], 'request': '/requests/1/4'} | {'decision': [['/b', '/c'], False, 1, '/b', 'canceled'], 'request': '/requests/1/4'} | Failed |
| fixture 6 | {'decision': [['/a', '/b'], False, 2, '/c', 'blocked'], 'request': '/requests/1/5'} | {'decision': [['/a', '/b'], False, 2, '/b', 'blocked'], 'request': '/requests/1/5'} | Failed |
SHA-256 / 59d984435c8f3cd83b1881ccc9edd27b5f571d440b55e083b1299a352629fea3
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, events, accepted, target, done, canceled):
return {'request': request, 'decision': [events + ([target] if accepted else []), done and not canceled, len(events), events[-1] if events else None, 'canceled' if canceled else ('redirect' if accepted else 'blocked')]}
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', '/b', '/a'], False, '/c', True, True), {'request': '/requests/' + str(N) + '/0', 'decision': [['/a', '/b', '/a'], False, 3, '/a', 'canceled']})
check('fixture 2', solve('/requests/' + str(N) + '/1', ['/a', '/b'], True, '/c', False, False), {'request': '/requests/' + str(N) + '/1', 'decision': [['/a', '/b', '/c'], False, 2, '/b', 'redirect']})
check('fixture 3', solve('/requests/' + str(N) + '/2', [], False, '/a', True, False), {'request': '/requests/' + str(N) + '/2', 'decision': [[], True, 0, None, 'blocked']})
check('fixture 4', solve('/requests/' + str(N) + '/3', [], True, '/a', False, False), {'request': '/requests/' + str(N) + '/3', 'decision': [['/a'], False, 0, None, 'redirect']})
check('fixture 5', solve('/requests/' + str(N) + '/4', ['/b'], True, '/c', True, True), {'request': '/requests/' + str(N) + '/4', 'decision': [['/b', '/c'], False, 1, '/b', 'canceled']})
check('fixture 6', solve('/requests/' + str(N) + '/5', ['/a', '/b'], False, '/c', False, False), {'request': '/requests/' + str(N) + '/5', 'decision': [['/a', '/b'], False, 2, '/b', 'blocked']})
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', '/b', '/a'], False, 3, '/a', 'canceled'], 'request': '/requests/1/0'} | {'decision': [['/a', '/b', '/a'], False, 3, '/a', 'canceled'], 'request': '/requests/1/0'} | Passed |
| fixture 2 | {'decision': [['/a', '/b', '/c'], False, 2, '/b', 'redirect'], 'request': '/requests/1/1'} | {'decision': [['/a', '/b', '/c'], False, 2, '/b', 'redirect'], 'request': '/requests/1/1'} | Passed |
| fixture 3 | {'decision': [[], True, 0, None, 'blocked'], 'request': '/requests/1/2'} | {'decision': [[], True, 0, None, 'blocked'], 'request': '/requests/1/2'} | Passed |
| fixture 4 | {'decision': [['/a'], False, 0, None, 'redirect'], 'request': '/requests/1/3'} | {'decision': [['/a'], False, 0, None, 'redirect'], 'request': '/requests/1/3'} | Passed |
| fixture 5 | {'decision': [['/b', '/c'], False, 1, '/b', 'canceled'], 'request': '/requests/1/4'} | {'decision': [['/b', '/c'], False, 1, '/b', 'canceled'], 'request': '/requests/1/4'} | Passed |
| fixture 6 | {'decision': [['/a', '/b'], False, 2, '/b', 'blocked'], 'request': '/requests/1/5'} | {'decision': [['/a', '/b'], False, 2, '/b', 'blocked'], 'request': '/requests/1/5'} | Passed |
SHA-256 / e8ee6c261d6c7a8f0f134377aa251974d311a013423f4c0df3ec6afd3cf9a18f
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 2026-09-29T14:41:31.299162+00:00.
Case digest / 8864f690beb2ea89d6490c501cf58a0b9285595d8ffc9ba7068026a2d3308b6f