FAILURE MAP
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FA-27841 / HTTP redirects / Open access

Select an unambiguous Location field without losing raw syntax: case insensitive name · case 01

Differently cased Location names are lost.

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

ROOT CAUSE

The case-insensitive-name decision uses "[v for k,v in lines if k == 'Location']"; this violates the stipulated controller policy.

VERIFIED REPAIR

At this decision use "[v for k,v in lines if k.lower() == 'location']", preserving the other controller outputs.

Unsuccessful approach: The partial repair uses "[v for k,v in lines if k == 'location']" and still fails an explicit boundary or control.

Case contract

Select an unambiguous Location field without losing raw syntax. 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, lines):
    return {'request': request, 'decision': [[v for k,v in lines if k == 'Location'], len([v for k,v in lines if k.lower() == 'location']) > 1, [v.strip(' \t') for k,v in lines if k.lower() == 'location'], [v for k,v in lines if k.lower() == 'location'], 'missing' if not any(k.lower() == 'location' for k,v in lines) else 'present']} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', [('Location', ' /a,b '), ('X', 'z')]), {'request': '/requests/' + str(N) + '/0', 'decision': [[' /a,b '], False, ['/a,b'], [' /a,b '], 'present']})
check('fixture 2', solve('/requests/' + str(N) + '/1', [('location', '/a b')]), {'request': '/requests/' + str(N) + '/1', 'decision': [['/a b'], False, ['/a b'], ['/a b'], 'present']})
check('fixture 3', solve('/requests/' + str(N) + '/2', [('LOCATION', '')]), {'request': '/requests/' + str(N) + '/2', 'decision': [[''], False, [''], [''], 'present']})
check('fixture 4', solve('/requests/' + str(N) + '/3', [('X', 'z')]), {'request': '/requests/' + str(N) + '/3', 'decision': [[], False, [], [], 'missing']})
check('fixture 5', solve('/requests/' + str(N) + '/4', [('Location', '/a'), ('location', '/b')]), {'request': '/requests/' + str(N) + '/4', 'decision': [['/a', '/b'], True, ['/a', '/b'], ['/a', '/b'], 'present']})
check('fixture 6', solve('/requests/' + str(N) + '/5', []), {'request': '/requests/' + str(N) + '/5', 'decision': [[], False, [], [], 'missing']})
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 '], False, ['/a,b'], [' /a,b '], 'present'], 'request': '/requests/1/0'}{'decision': [[' /a,b '], False, ['/a,b'], [' /a,b '], 'present'], 'request': '/requests/1/0'}Passed
fixture 2{'decision': [[], False, ['/a b'], ['/a b'], 'present'], 'request': '/requests/1/1'}{'decision': [['/a b'], False, ['/a b'], ['/a b'], 'present'], 'request': '/requests/1/1'}Failed
fixture 3{'decision': [[], False, [''], [''], 'present'], 'request': '/requests/1/2'}{'decision': [[''], False, [''], [''], 'present'], 'request': '/requests/1/2'}Failed
fixture 4{'decision': [[], False, [], [], 'missing'], 'request': '/requests/1/3'}{'decision': [[], False, [], [], 'missing'], 'request': '/requests/1/3'}Passed
fixture 5{'decision': [['/a'], True, ['/a', '/b'], ['/a', '/b'], 'present'], 'request': '/requests/1/4'}{'decision': [['/a', '/b'], True, ['/a', '/b'], ['/a', '/b'], 'present'], 'request': '/requests/1/4'}Failed
fixture 6{'decision': [[], False, [], [], 'missing'], 'request': '/requests/1/5'}{'decision': [[], False, [], [], 'missing'], 'request': '/requests/1/5'}Passed

SHA-256 / bdce3e5226b8d88957dc0d788921bad870f58cfb9dd32bb84ea26a0d0934f0d3

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, lines):
    return {'request': request, 'decision': [[v for k,v in lines if k == 'location'], len([v for k,v in lines if k.lower() == 'location']) > 1, [v.strip(' \t') for k,v in lines if k.lower() == 'location'], [v for k,v in lines if k.lower() == 'location'], 'missing' if not any(k.lower() == 'location' for k,v in lines) else 'present']} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', [('Location', ' /a,b '), ('X', 'z')]), {'request': '/requests/' + str(N) + '/0', 'decision': [[' /a,b '], False, ['/a,b'], [' /a,b '], 'present']})
check('fixture 2', solve('/requests/' + str(N) + '/1', [('location', '/a b')]), {'request': '/requests/' + str(N) + '/1', 'decision': [['/a b'], False, ['/a b'], ['/a b'], 'present']})
check('fixture 3', solve('/requests/' + str(N) + '/2', [('LOCATION', '')]), {'request': '/requests/' + str(N) + '/2', 'decision': [[''], False, [''], [''], 'present']})
check('fixture 4', solve('/requests/' + str(N) + '/3', [('X', 'z')]), {'request': '/requests/' + str(N) + '/3', 'decision': [[], False, [], [], 'missing']})
check('fixture 5', solve('/requests/' + str(N) + '/4', [('Location', '/a'), ('location', '/b')]), {'request': '/requests/' + str(N) + '/4', 'decision': [['/a', '/b'], True, ['/a', '/b'], ['/a', '/b'], 'present']})
check('fixture 6', solve('/requests/' + str(N) + '/5', []), {'request': '/requests/' + str(N) + '/5', 'decision': [[], False, [], [], 'missing']})
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': [[], False, ['/a,b'], [' /a,b '], 'present'], 'request': '/requests/1/0'}{'decision': [[' /a,b '], False, ['/a,b'], [' /a,b '], 'present'], 'request': '/requests/1/0'}Failed
fixture 2{'decision': [['/a b'], False, ['/a b'], ['/a b'], 'present'], 'request': '/requests/1/1'}{'decision': [['/a b'], False, ['/a b'], ['/a b'], 'present'], 'request': '/requests/1/1'}Passed
fixture 3{'decision': [[], False, [''], [''], 'present'], 'request': '/requests/1/2'}{'decision': [[''], False, [''], [''], 'present'], 'request': '/requests/1/2'}Failed
fixture 4{'decision': [[], False, [], [], 'missing'], 'request': '/requests/1/3'}{'decision': [[], False, [], [], 'missing'], 'request': '/requests/1/3'}Passed
fixture 5{'decision': [['/b'], True, ['/a', '/b'], ['/a', '/b'], 'present'], 'request': '/requests/1/4'}{'decision': [['/a', '/b'], True, ['/a', '/b'], ['/a', '/b'], 'present'], 'request': '/requests/1/4'}Failed
fixture 6{'decision': [[], False, [], [], 'missing'], 'request': '/requests/1/5'}{'decision': [[], False, [], [], 'missing'], 'request': '/requests/1/5'}Passed

SHA-256 / a3f2a5d023f0c90b212c56c6fc7968d3558ff28a50584eef3fff25bee916224a

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, lines):
    return {'request': request, 'decision': [[v for k,v in lines if k.lower() == 'location'], len([v for k,v in lines if k.lower() == 'location']) > 1, [v.strip(' \t') for k,v in lines if k.lower() == 'location'], [v for k,v in lines if k.lower() == 'location'], 'missing' if not any(k.lower() == 'location' for k,v in lines) else 'present']} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', [('Location', ' /a,b '), ('X', 'z')]), {'request': '/requests/' + str(N) + '/0', 'decision': [[' /a,b '], False, ['/a,b'], [' /a,b '], 'present']})
check('fixture 2', solve('/requests/' + str(N) + '/1', [('location', '/a b')]), {'request': '/requests/' + str(N) + '/1', 'decision': [['/a b'], False, ['/a b'], ['/a b'], 'present']})
check('fixture 3', solve('/requests/' + str(N) + '/2', [('LOCATION', '')]), {'request': '/requests/' + str(N) + '/2', 'decision': [[''], False, [''], [''], 'present']})
check('fixture 4', solve('/requests/' + str(N) + '/3', [('X', 'z')]), {'request': '/requests/' + str(N) + '/3', 'decision': [[], False, [], [], 'missing']})
check('fixture 5', solve('/requests/' + str(N) + '/4', [('Location', '/a'), ('location', '/b')]), {'request': '/requests/' + str(N) + '/4', 'decision': [['/a', '/b'], True, ['/a', '/b'], ['/a', '/b'], 'present']})
check('fixture 6', solve('/requests/' + str(N) + '/5', []), {'request': '/requests/' + str(N) + '/5', 'decision': [[], False, [], [], 'missing']})
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 '], False, ['/a,b'], [' /a,b '], 'present'], 'request': '/requests/1/0'}{'decision': [[' /a,b '], False, ['/a,b'], [' /a,b '], 'present'], 'request': '/requests/1/0'}Passed
fixture 2{'decision': [['/a b'], False, ['/a b'], ['/a b'], 'present'], 'request': '/requests/1/1'}{'decision': [['/a b'], False, ['/a b'], ['/a b'], 'present'], 'request': '/requests/1/1'}Passed
fixture 3{'decision': [[''], False, [''], [''], 'present'], 'request': '/requests/1/2'}{'decision': [[''], False, [''], [''], 'present'], 'request': '/requests/1/2'}Passed
fixture 4{'decision': [[], False, [], [], 'missing'], 'request': '/requests/1/3'}{'decision': [[], False, [], [], 'missing'], 'request': '/requests/1/3'}Passed
fixture 5{'decision': [['/a', '/b'], True, ['/a', '/b'], ['/a', '/b'], 'present'], 'request': '/requests/1/4'}{'decision': [['/a', '/b'], True, ['/a', '/b'], ['/a', '/b'], 'present'], 'request': '/requests/1/4'}Passed
fixture 6{'decision': [[], False, [], [], 'missing'], 'request': '/requests/1/5'}{'decision': [[], False, [], [], 'missing'], 'request': '/requests/1/5'}Passed

SHA-256 / 1eaeb7ff007000e5aeef3a6be05b0b42cc1dd54fd647a89b3d9aeb368a85668e

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 2026-09-29T14:41:28.668543+00:00.

Case digest / f620bbdc9bc49ce3c7422a223c4796f07ea1ac228e24f8767dea1a00a69965b1