FA-28766 / HTTP redirects / Open access
Commit a redirect chain using terminal document semantics and the original navigation intent: referrer initiator not intermediate · case 01
Commit a redirect chain using terminal document semantics and the original navigation intent: the referrer initiator not intermediate branch emits an incorrect decision.
ROOT CAUSE
The referrer-initiator-not-intermediate decision uses 'chain[-2] if len(chain)>1 else chain[0]'; this violates the stipulated controller policy.
THE FAILURE
The referrer-initiator-not-intermediate decision uses 'chain[-2] if len(chain)>1 else chain[0]'; this violates the stipulated controller policy.
Unsuccessful approach: The partial repair uses 'chain[0]' and still fails an explicit boundary or control.
Case contract
Commit a redirect chain using terminal document semantics and the original navigation intent. 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, chain, methods, state, download, activation, replace, initiator, allows):
return {'request': request, 'decision': [[] if download else [chain[-1]], methods[-1] not in ('GET','HEAD'), state, 1 if activation else 0, replace, chain[-2] if len(chain)>1 else chain[0], [u for u,ok in zip(chain,allows) if not ok], urlsplit(chain[-1]).netloc, 'download' if download else 'document', {'requested':chain[0],'committed':None if download else chain[-1]}]}
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', ['https://a/x', 'https://b/y', 'https://c/z'], ['POST', 'GET', 'GET'], {'view': 'v'}, False, True, False, 'https://start/home', [True, False, True]), {'request': '/requests/' + str(N) + '/0', 'decision': [['https://c/z'], False, {'view': 'v'}, 1, False, 'https://start/home', ['https://b/y'], 'c', 'document', {'requested': 'https://a/x', 'committed': 'https://c/z'}]})
check('fixture 2', solve('/requests/' + str(N) + '/1', ['https://a/x'], ['GET'], {'view': 'q'}, False, True, True, 'https://start/home', [True]), {'request': '/requests/' + str(N) + '/1', 'decision': [['https://a/x'], False, {'view': 'q'}, 1, True, 'https://start/home', [], 'a', 'document', {'requested': 'https://a/x', 'committed': 'https://a/x'}]})
check('fixture 3', solve('/requests/' + str(N) + '/2', ['https://a/x', 'https://b/file'], ['GET', 'GET'], {}, True, False, False, 'https://start/a', [True, True]), {'request': '/requests/' + str(N) + '/2', 'decision': [[], False, {}, 0, False, 'https://start/a', [], 'b', 'download', {'requested': 'https://a/x', 'committed': None}]})
check('fixture 4', solve('/requests/' + str(N) + '/3', ['https://a/x', 'https://b/y'], ['POST', 'POST'], {'form': 'a'}, False, False, True, 'https://start/b', [False, True]), {'request': '/requests/' + str(N) + '/3', 'decision': [['https://b/y'], True, {'form': 'a'}, 0, True, 'https://start/b', ['https://a/x'], 'b', 'document', {'requested': 'https://a/x', 'committed': 'https://b/y'}]})
check('fixture 5', solve('/requests/' + str(N) + '/4', ['https://a/x', 'https://a/y'], ['GET', 'HEAD'], {}, False, True, False, 'https://start/c', [True, True]), {'request': '/requests/' + str(N) + '/4', 'decision': [['https://a/y'], False, {}, 1, False, 'https://start/c', [], 'a', 'document', {'requested': 'https://a/x', 'committed': 'https://a/y'}]})
check('fixture 6', solve('/requests/' + str(N) + '/5', ['https://a/x', 'https://b/file'], ['POST', 'GET'], {'download': 'd'}, True, True, True, 'https://start/d', [True, False]), {'request': '/requests/' + str(N) + '/5', 'decision': [[], False, {'download': 'd'}, 1, True, 'https://start/d', ['https://b/file'], 'b', 'download', {'requested': 'https://a/x', 'committed': None}]})
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': [['https://c/z'], False, {'view': 'v'}, 1, False, 'https://b/y', ['https://b/y'], 'c', 'document', {'committed': 'https://c/z', 'requested': 'https://a/x'}], 'request': '/requests/1/0'} | {'decision': [['https://c/z'], False, {'view': 'v'}, 1, False, 'https://start/home', ['https://b/y'], 'c', 'document', {'committed': 'https://c/z', 'requested': 'https://a/x'}], 'request': '/requests/1/0'} | Failed |
| fixture 2 | {'decision': [['https://a/x'], False, {'view': 'q'}, 1, True, 'https://a/x', [], 'a', 'document', {'committed': 'https://a/x', 'requested': 'https://a/x'}], 'request': '/requests/1/1'} | {'decision': [['https://a/x'], False, {'view': 'q'}, 1, True, 'https://start/home', [], 'a', 'document', {'committed': 'https://a/x', 'requested': 'https://a/x'}], 'request': '/requests/1/1'} | Failed |
| fixture 3 | {'decision': [[], False, {}, 0, False, 'https://a/x', [], 'b', 'download', {'committed': None, 'requested': 'https://a/x'}], 'request': '/requests/1/2'} | {'decision': [[], False, {}, 0, False, 'https://start/a', [], 'b', 'download', {'committed': None, 'requested': 'https://a/x'}], 'request': '/requests/1/2'} | Failed |
| fixture 4 | {'decision': [['https://b/y'], True, {'form': 'a'}, 0, True, 'https://a/x', ['https://a/x'], 'b', 'document', {'committed': 'https://b/y', 'requested': 'https://a/x'}], 'request': '/requests/1/3'} | {'decision': [['https://b/y'], True, {'form': 'a'}, 0, True, 'https://start/b', ['https://a/x'], 'b', 'document', {'committed': 'https://b/y', 'requested': 'https://a/x'}], 'request': '/requests/1/3'} | Failed |
| fixture 5 | {'decision': [['https://a/y'], False, {}, 1, False, 'https://a/x', [], 'a', 'document', {'committed': 'https://a/y', 'requested': 'https://a/x'}], 'request': '/requests/1/4'} | {'decision': [['https://a/y'], False, {}, 1, False, 'https://start/c', [], 'a', 'document', {'committed': 'https://a/y', 'requested': 'https://a/x'}], 'request': '/requests/1/4'} | Failed |
| fixture 6 | {'decision': [[], False, {'download': 'd'}, 1, True, 'https://a/x', ['https://b/file'], 'b', 'download', {'committed': None, 'requested': 'https://a/x'}], 'request': '/requests/1/5'} | {'decision': [[], False, {'download': 'd'}, 1, True, 'https://start/d', ['https://b/file'], 'b', 'download', {'committed': None, 'requested': 'https://a/x'}], 'request': '/requests/1/5'} | Failed |
SHA-256 / 5dbe1cc2687443faaf7859b98551c7bb20637ceab5dc66872da6cf4767124576
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, chain, methods, state, download, activation, replace, initiator, allows):
return {'request': request, 'decision': [[] if download else [chain[-1]], methods[-1] not in ('GET','HEAD'), state, 1 if activation else 0, replace, chain[0], [u for u,ok in zip(chain,allows) if not ok], urlsplit(chain[-1]).netloc, 'download' if download else 'document', {'requested':chain[0],'committed':None if download else chain[-1]}]}
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', ['https://a/x', 'https://b/y', 'https://c/z'], ['POST', 'GET', 'GET'], {'view': 'v'}, False, True, False, 'https://start/home', [True, False, True]), {'request': '/requests/' + str(N) + '/0', 'decision': [['https://c/z'], False, {'view': 'v'}, 1, False, 'https://start/home', ['https://b/y'], 'c', 'document', {'requested': 'https://a/x', 'committed': 'https://c/z'}]})
check('fixture 2', solve('/requests/' + str(N) + '/1', ['https://a/x'], ['GET'], {'view': 'q'}, False, True, True, 'https://start/home', [True]), {'request': '/requests/' + str(N) + '/1', 'decision': [['https://a/x'], False, {'view': 'q'}, 1, True, 'https://start/home', [], 'a', 'document', {'requested': 'https://a/x', 'committed': 'https://a/x'}]})
check('fixture 3', solve('/requests/' + str(N) + '/2', ['https://a/x', 'https://b/file'], ['GET', 'GET'], {}, True, False, False, 'https://start/a', [True, True]), {'request': '/requests/' + str(N) + '/2', 'decision': [[], False, {}, 0, False, 'https://start/a', [], 'b', 'download', {'requested': 'https://a/x', 'committed': None}]})
check('fixture 4', solve('/requests/' + str(N) + '/3', ['https://a/x', 'https://b/y'], ['POST', 'POST'], {'form': 'a'}, False, False, True, 'https://start/b', [False, True]), {'request': '/requests/' + str(N) + '/3', 'decision': [['https://b/y'], True, {'form': 'a'}, 0, True, 'https://start/b', ['https://a/x'], 'b', 'document', {'requested': 'https://a/x', 'committed': 'https://b/y'}]})
check('fixture 5', solve('/requests/' + str(N) + '/4', ['https://a/x', 'https://a/y'], ['GET', 'HEAD'], {}, False, True, False, 'https://start/c', [True, True]), {'request': '/requests/' + str(N) + '/4', 'decision': [['https://a/y'], False, {}, 1, False, 'https://start/c', [], 'a', 'document', {'requested': 'https://a/x', 'committed': 'https://a/y'}]})
check('fixture 6', solve('/requests/' + str(N) + '/5', ['https://a/x', 'https://b/file'], ['POST', 'GET'], {'download': 'd'}, True, True, True, 'https://start/d', [True, False]), {'request': '/requests/' + str(N) + '/5', 'decision': [[], False, {'download': 'd'}, 1, True, 'https://start/d', ['https://b/file'], 'b', 'download', {'requested': 'https://a/x', 'committed': None}]})
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': [['https://c/z'], False, {'view': 'v'}, 1, False, 'https://a/x', ['https://b/y'], 'c', 'document', {'committed': 'https://c/z', 'requested': 'https://a/x'}], 'request': '/requests/1/0'} | {'decision': [['https://c/z'], False, {'view': 'v'}, 1, False, 'https://start/home', ['https://b/y'], 'c', 'document', {'committed': 'https://c/z', 'requested': 'https://a/x'}], 'request': '/requests/1/0'} | Failed |
| fixture 2 | {'decision': [['https://a/x'], False, {'view': 'q'}, 1, True, 'https://a/x', [], 'a', 'document', {'committed': 'https://a/x', 'requested': 'https://a/x'}], 'request': '/requests/1/1'} | {'decision': [['https://a/x'], False, {'view': 'q'}, 1, True, 'https://start/home', [], 'a', 'document', {'committed': 'https://a/x', 'requested': 'https://a/x'}], 'request': '/requests/1/1'} | Failed |
| fixture 3 | {'decision': [[], False, {}, 0, False, 'https://a/x', [], 'b', 'download', {'committed': None, 'requested': 'https://a/x'}], 'request': '/requests/1/2'} | {'decision': [[], False, {}, 0, False, 'https://start/a', [], 'b', 'download', {'committed': None, 'requested': 'https://a/x'}], 'request': '/requests/1/2'} | Failed |
| fixture 4 | {'decision': [['https://b/y'], True, {'form': 'a'}, 0, True, 'https://a/x', ['https://a/x'], 'b', 'document', {'committed': 'https://b/y', 'requested': 'https://a/x'}], 'request': '/requests/1/3'} | {'decision': [['https://b/y'], True, {'form': 'a'}, 0, True, 'https://start/b', ['https://a/x'], 'b', 'document', {'committed': 'https://b/y', 'requested': 'https://a/x'}], 'request': '/requests/1/3'} | Failed |
| fixture 5 | {'decision': [['https://a/y'], False, {}, 1, False, 'https://a/x', [], 'a', 'document', {'committed': 'https://a/y', 'requested': 'https://a/x'}], 'request': '/requests/1/4'} | {'decision': [['https://a/y'], False, {}, 1, False, 'https://start/c', [], 'a', 'document', {'committed': 'https://a/y', 'requested': 'https://a/x'}], 'request': '/requests/1/4'} | Failed |
| fixture 6 | {'decision': [[], False, {'download': 'd'}, 1, True, 'https://a/x', ['https://b/file'], 'b', 'download', {'committed': None, 'requested': 'https://a/x'}], 'request': '/requests/1/5'} | {'decision': [[], False, {'download': 'd'}, 1, True, 'https://start/d', ['https://b/file'], 'b', 'download', {'committed': None, 'requested': 'https://a/x'}], 'request': '/requests/1/5'} | Failed |
SHA-256 / e2d171beb30c348ee0e8f9102f21454ba18a76dbf72aecef978aa51ce6f9d101
HELD IN THE MEMBER ARCHIVE
The verified repair and its recorded checks are member-only.
This mechanism has 6 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 2026-09-29T14:41:37.049365+00:00.
Case digest / 2528deda7fb4bc3cd75c232ce1484ea23b18e2eb4e400126133e1d9b373f45bf