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FA-28126 / HTTP redirects / Open access

Expose redirect events in request order without false completion: redirect count from events · case 01

Expose redirect events in request order without false completion: the redirect count from events branch emits an incorrect decision.

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

ROOT CAUSE

The redirect-count-from-events decision uses 'len(set(events))'; this violates the stipulated controller policy.

VERIFIED REPAIR

At this decision use 'len(events)', preserving the other controller outputs.

Unsuccessful approach: The partial repair uses 'max(0,len(events)-1)' 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(set(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 fixtureActualExpectedOutcome
fixture 1{'decision': [['/a', '/b', '/a'], False, 2, '/a', '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, '/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 / d1263531b61d3a96ed3a4f5e58c841be5c88397fbfb41697f7a5c5844a2c1a22

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, max(0,len(events)-1), 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 fixtureActualExpectedOutcome
fixture 1{'decision': [['/a', '/b', '/a'], False, 2, '/a', '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, 1, '/b', '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, 0, '/b', 'canceled'], 'request': '/requests/1/4'}{'decision': [['/b', '/c'], False, 1, '/b', 'canceled'], 'request': '/requests/1/4'}Failed
fixture 6{'decision': [['/a', '/b'], False, 1, '/b', 'blocked'], 'request': '/requests/1/5'}{'decision': [['/a', '/b'], False, 2, '/b', 'blocked'], 'request': '/requests/1/5'}Failed

SHA-256 / 9d5b6d90e423fab660b9b015858794aa4008326436c8e1db22139622db34d1e8

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 fixtureActualExpectedOutcome
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 2026-09-29T14:41:31.217693+00:00.

Case digest / f5971df751659d8988feb2f0348857a3f713337f3ddef9a7d0f8684d49d3f86a