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FA-28181 / HTTP redirects / Open access

Release an intermediate response before following its target: connection vs stream · case 01

Release an intermediate response before following its target: the connection vs stream branch emits an incorrect decision.

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

ROOT CAUSE

The connection-vs-stream decision uses "'connection'"; this violates the stipulated controller policy.

VERIFIED REPAIR

At this decision use "'stream' if http2 else 'connection'", preserving the other controller outputs.

Unsuccessful approach: The partial repair uses "'stream'" and still fails an explicit boundary or control.

Case contract

Release an intermediate response before following its 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, drained, remaining, reusable, closed, canceled, http2):
    return {'request': request, 'decision': [not drained and remaining > 0, reusable and drained and not closed, not http2 and remaining > 0 and not reusable, http2 and remaining > 0, not canceled and not closed, 'eof' if remaining == 0 else 'pending', not closed, remaining if not drained else 0, 'connection', 'released' if closed else ('canceling' if canceled else 'owned')]} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', False, 8, True, False, False, False), {'request': '/requests/' + str(N) + '/0', 'decision': [True, False, False, False, True, 'pending', True, 8, 'connection', 'owned']})
check('fixture 2', solve('/requests/' + str(N) + '/1', True, 0, True, False, False, False), {'request': '/requests/' + str(N) + '/1', 'decision': [False, True, False, False, True, 'eof', True, 0, 'connection', 'owned']})
check('fixture 3', solve('/requests/' + str(N) + '/2', False, 3, False, False, False, False), {'request': '/requests/' + str(N) + '/2', 'decision': [True, False, True, False, True, 'pending', True, 3, 'connection', 'owned']})
check('fixture 4', solve('/requests/' + str(N) + '/3', False, 5, True, False, True, True), {'request': '/requests/' + str(N) + '/3', 'decision': [True, False, False, True, False, 'pending', True, 5, 'stream', 'canceling']})
check('fixture 5', solve('/requests/' + str(N) + '/4', True, 0, True, True, False, True), {'request': '/requests/' + str(N) + '/4', 'decision': [False, False, False, False, False, 'eof', False, 0, 'stream', 'released']})
check('fixture 6', solve('/requests/' + str(N) + '/5', False, 0, False, True, True, False), {'request': '/requests/' + str(N) + '/5', 'decision': [False, False, False, False, False, 'eof', False, 0, 'connection', 'released']})
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': [True, False, False, False, True, 'pending', True, 8, 'connection', 'owned'], 'request': '/requests/1/0'}{'decision': [True, False, False, False, True, 'pending', True, 8, 'connection', 'owned'], 'request': '/requests/1/0'}Passed
fixture 2{'decision': [False, True, False, False, True, 'eof', True, 0, 'connection', 'owned'], 'request': '/requests/1/1'}{'decision': [False, True, False, False, True, 'eof', True, 0, 'connection', 'owned'], 'request': '/requests/1/1'}Passed
fixture 3{'decision': [True, False, True, False, True, 'pending', True, 3, 'connection', 'owned'], 'request': '/requests/1/2'}{'decision': [True, False, True, False, True, 'pending', True, 3, 'connection', 'owned'], 'request': '/requests/1/2'}Passed
fixture 4{'decision': [True, False, False, True, False, 'pending', True, 5, 'connection', 'canceling'], 'request': '/requests/1/3'}{'decision': [True, False, False, True, False, 'pending', True, 5, 'stream', 'canceling'], 'request': '/requests/1/3'}Failed
fixture 5{'decision': [False, False, False, False, False, 'eof', False, 0, 'connection', 'released'], 'request': '/requests/1/4'}{'decision': [False, False, False, False, False, 'eof', False, 0, 'stream', 'released'], 'request': '/requests/1/4'}Failed
fixture 6{'decision': [False, False, False, False, False, 'eof', False, 0, 'connection', 'released'], 'request': '/requests/1/5'}{'decision': [False, False, False, False, False, 'eof', False, 0, 'connection', 'released'], 'request': '/requests/1/5'}Passed

SHA-256 / e4bae157cc61f7222106786acc69348c39a4709b2c1cbbdc39943dfedc749abc

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, drained, remaining, reusable, closed, canceled, http2):
    return {'request': request, 'decision': [not drained and remaining > 0, reusable and drained and not closed, not http2 and remaining > 0 and not reusable, http2 and remaining > 0, not canceled and not closed, 'eof' if remaining == 0 else 'pending', not closed, remaining if not drained else 0, 'stream', 'released' if closed else ('canceling' if canceled else 'owned')]} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', False, 8, True, False, False, False), {'request': '/requests/' + str(N) + '/0', 'decision': [True, False, False, False, True, 'pending', True, 8, 'connection', 'owned']})
check('fixture 2', solve('/requests/' + str(N) + '/1', True, 0, True, False, False, False), {'request': '/requests/' + str(N) + '/1', 'decision': [False, True, False, False, True, 'eof', True, 0, 'connection', 'owned']})
check('fixture 3', solve('/requests/' + str(N) + '/2', False, 3, False, False, False, False), {'request': '/requests/' + str(N) + '/2', 'decision': [True, False, True, False, True, 'pending', True, 3, 'connection', 'owned']})
check('fixture 4', solve('/requests/' + str(N) + '/3', False, 5, True, False, True, True), {'request': '/requests/' + str(N) + '/3', 'decision': [True, False, False, True, False, 'pending', True, 5, 'stream', 'canceling']})
check('fixture 5', solve('/requests/' + str(N) + '/4', True, 0, True, True, False, True), {'request': '/requests/' + str(N) + '/4', 'decision': [False, False, False, False, False, 'eof', False, 0, 'stream', 'released']})
check('fixture 6', solve('/requests/' + str(N) + '/5', False, 0, False, True, True, False), {'request': '/requests/' + str(N) + '/5', 'decision': [False, False, False, False, False, 'eof', False, 0, 'connection', 'released']})
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': [True, False, False, False, True, 'pending', True, 8, 'stream', 'owned'], 'request': '/requests/1/0'}{'decision': [True, False, False, False, True, 'pending', True, 8, 'connection', 'owned'], 'request': '/requests/1/0'}Failed
fixture 2{'decision': [False, True, False, False, True, 'eof', True, 0, 'stream', 'owned'], 'request': '/requests/1/1'}{'decision': [False, True, False, False, True, 'eof', True, 0, 'connection', 'owned'], 'request': '/requests/1/1'}Failed
fixture 3{'decision': [True, False, True, False, True, 'pending', True, 3, 'stream', 'owned'], 'request': '/requests/1/2'}{'decision': [True, False, True, False, True, 'pending', True, 3, 'connection', 'owned'], 'request': '/requests/1/2'}Failed
fixture 4{'decision': [True, False, False, True, False, 'pending', True, 5, 'stream', 'canceling'], 'request': '/requests/1/3'}{'decision': [True, False, False, True, False, 'pending', True, 5, 'stream', 'canceling'], 'request': '/requests/1/3'}Passed
fixture 5{'decision': [False, False, False, False, False, 'eof', False, 0, 'stream', 'released'], 'request': '/requests/1/4'}{'decision': [False, False, False, False, False, 'eof', False, 0, 'stream', 'released'], 'request': '/requests/1/4'}Passed
fixture 6{'decision': [False, False, False, False, False, 'eof', False, 0, 'stream', 'released'], 'request': '/requests/1/5'}{'decision': [False, False, False, False, False, 'eof', False, 0, 'connection', 'released'], 'request': '/requests/1/5'}Failed

SHA-256 / 823c31423373dea3a56203bb5ac006697d1a044ae6cc602dc97dded3d3dfbe36

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, drained, remaining, reusable, closed, canceled, http2):
    return {'request': request, 'decision': [not drained and remaining > 0, reusable and drained and not closed, not http2 and remaining > 0 and not reusable, http2 and remaining > 0, not canceled and not closed, 'eof' if remaining == 0 else 'pending', not closed, remaining if not drained else 0, 'stream' if http2 else 'connection', 'released' if closed else ('canceling' if canceled else 'owned')]} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', False, 8, True, False, False, False), {'request': '/requests/' + str(N) + '/0', 'decision': [True, False, False, False, True, 'pending', True, 8, 'connection', 'owned']})
check('fixture 2', solve('/requests/' + str(N) + '/1', True, 0, True, False, False, False), {'request': '/requests/' + str(N) + '/1', 'decision': [False, True, False, False, True, 'eof', True, 0, 'connection', 'owned']})
check('fixture 3', solve('/requests/' + str(N) + '/2', False, 3, False, False, False, False), {'request': '/requests/' + str(N) + '/2', 'decision': [True, False, True, False, True, 'pending', True, 3, 'connection', 'owned']})
check('fixture 4', solve('/requests/' + str(N) + '/3', False, 5, True, False, True, True), {'request': '/requests/' + str(N) + '/3', 'decision': [True, False, False, True, False, 'pending', True, 5, 'stream', 'canceling']})
check('fixture 5', solve('/requests/' + str(N) + '/4', True, 0, True, True, False, True), {'request': '/requests/' + str(N) + '/4', 'decision': [False, False, False, False, False, 'eof', False, 0, 'stream', 'released']})
check('fixture 6', solve('/requests/' + str(N) + '/5', False, 0, False, True, True, False), {'request': '/requests/' + str(N) + '/5', 'decision': [False, False, False, False, False, 'eof', False, 0, 'connection', 'released']})
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': [True, False, False, False, True, 'pending', True, 8, 'connection', 'owned'], 'request': '/requests/1/0'}{'decision': [True, False, False, False, True, 'pending', True, 8, 'connection', 'owned'], 'request': '/requests/1/0'}Passed
fixture 2{'decision': [False, True, False, False, True, 'eof', True, 0, 'connection', 'owned'], 'request': '/requests/1/1'}{'decision': [False, True, False, False, True, 'eof', True, 0, 'connection', 'owned'], 'request': '/requests/1/1'}Passed
fixture 3{'decision': [True, False, True, False, True, 'pending', True, 3, 'connection', 'owned'], 'request': '/requests/1/2'}{'decision': [True, False, True, False, True, 'pending', True, 3, 'connection', 'owned'], 'request': '/requests/1/2'}Passed
fixture 4{'decision': [True, False, False, True, False, 'pending', True, 5, 'stream', 'canceling'], 'request': '/requests/1/3'}{'decision': [True, False, False, True, False, 'pending', True, 5, 'stream', 'canceling'], 'request': '/requests/1/3'}Passed
fixture 5{'decision': [False, False, False, False, False, 'eof', False, 0, 'stream', 'released'], 'request': '/requests/1/4'}{'decision': [False, False, False, False, False, 'eof', False, 0, 'stream', 'released'], 'request': '/requests/1/4'}Passed
fixture 6{'decision': [False, False, False, False, False, 'eof', False, 0, 'connection', 'released'], 'request': '/requests/1/5'}{'decision': [False, False, False, False, False, 'eof', False, 0, 'connection', 'released'], 'request': '/requests/1/5'}Passed

SHA-256 / 204b11e22fc592885bad3b3fe88a5f7148c2a772a36a293f7ecc886355101675

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 2026-09-29T14:41:31.663005+00:00.

Case digest / cb837bd069c3d99671de5422eaacdb6d2758a863cf40d08edc9643e075c1c053