FA-26426 / HTTP ranges / Open access

Partial cache entries distinguish selected language variants · case 01

Partial cache entries distinguish selected language variants.

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

ROOT CAUSE

The language-variant-cache-key decision uses return [uri,coding].

VERIFIED REPAIR

Apply the bounded decision exactly: return [uri,language,coding]

Unsuccessful approach: The partial repair uses return [uri,language], which still violates the stated contract.

Case contract

Return composite partial-object cache identity [uri,language,coding]. Empty language represents the default variant and is retained.

Why this case matters

Range responses combine representation identity, conditional requests, framing, and partial-object state.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(uri, language, coding):
    return [uri,coding]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('language-variant-cache-key fixture 0', solve("/r"+str(N),"en","gzip"), ["/r"+str(N),"en","gzip"])
check('language-variant-cache-key fixture 1', solve("/r","fr","identity"), ["/r","fr","identity"])
check('language-variant-cache-key fixture 2', solve("/r","","identity"), ["/r","","identity"])
check('language-variant-cache-key fixture 3', solve("/x","en","identity"), ["/x","en","identity"])
check('language-variant-cache-key fixture 4', solve("/r","en","br"), ["/r","en","br"])
check('language-variant-cache-key fixture 5', solve("/r","fr","gzip"), ["/r","fr","gzip"])
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
language-variant-cache-key fixture 0	`['/r1', 'gzip']`	`['/r1', 'en', 'gzip']`	Failed
language-variant-cache-key fixture 1	`['/r', 'identity']`	`['/r', 'fr', 'identity']`	Failed
language-variant-cache-key fixture 2	`['/r', 'identity']`	`['/r', '', 'identity']`	Failed
language-variant-cache-key fixture 3	`['/x', 'identity']`	`['/x', 'en', 'identity']`	Failed
language-variant-cache-key fixture 4	`['/r', 'br']`	`['/r', 'en', 'br']`	Failed
language-variant-cache-key fixture 5	`['/r', 'gzip']`	`['/r', 'fr', 'gzip']`	Failed

SHA-256 / cbf5d3894ccc42d4a3ac5d2b7be5ac916875e10026af6daf2c5ea27c25bcbda0

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(uri, language, coding):
    return [uri,language]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('language-variant-cache-key fixture 0', solve("/r"+str(N),"en","gzip"), ["/r"+str(N),"en","gzip"])
check('language-variant-cache-key fixture 1', solve("/r","fr","identity"), ["/r","fr","identity"])
check('language-variant-cache-key fixture 2', solve("/r","","identity"), ["/r","","identity"])
check('language-variant-cache-key fixture 3', solve("/x","en","identity"), ["/x","en","identity"])
check('language-variant-cache-key fixture 4', solve("/r","en","br"), ["/r","en","br"])
check('language-variant-cache-key fixture 5', solve("/r","fr","gzip"), ["/r","fr","gzip"])
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
language-variant-cache-key fixture 0	`['/r1', 'en']`	`['/r1', 'en', 'gzip']`	Failed
language-variant-cache-key fixture 1	`['/r', 'fr']`	`['/r', 'fr', 'identity']`	Failed
language-variant-cache-key fixture 2	`['/r', '']`	`['/r', '', 'identity']`	Failed
language-variant-cache-key fixture 3	`['/x', 'en']`	`['/x', 'en', 'identity']`	Failed
language-variant-cache-key fixture 4	`['/r', 'en']`	`['/r', 'en', 'br']`	Failed
language-variant-cache-key fixture 5	`['/r', 'fr']`	`['/r', 'fr', 'gzip']`	Failed

SHA-256 / 7e5f15e81ba6d933b563589f2b7b011461b337ab1b27dbc20c8b367965d03dd3

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(uri, language, coding):
    return [uri,language,coding]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('language-variant-cache-key fixture 0', solve("/r"+str(N),"en","gzip"), ["/r"+str(N),"en","gzip"])
check('language-variant-cache-key fixture 1', solve("/r","fr","identity"), ["/r","fr","identity"])
check('language-variant-cache-key fixture 2', solve("/r","","identity"), ["/r","","identity"])
check('language-variant-cache-key fixture 3', solve("/x","en","identity"), ["/x","en","identity"])
check('language-variant-cache-key fixture 4', solve("/r","en","br"), ["/r","en","br"])
check('language-variant-cache-key fixture 5', solve("/r","fr","gzip"), ["/r","fr","gzip"])
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
language-variant-cache-key fixture 0	`['/r1', 'en', 'gzip']`	`['/r1', 'en', 'gzip']`	Passed
language-variant-cache-key fixture 1	`['/r', 'fr', 'identity']`	`['/r', 'fr', 'identity']`	Passed
language-variant-cache-key fixture 2	`['/r', '', 'identity']`	`['/r', '', 'identity']`	Passed
language-variant-cache-key fixture 3	`['/x', 'en', 'identity']`	`['/x', 'en', 'identity']`	Passed
language-variant-cache-key fixture 4	`['/r', 'en', 'br']`	`['/r', 'en', 'br']`	Passed
language-variant-cache-key fixture 5	`['/r', 'fr', 'gzip']`	`['/r', 'fr', 'gzip']`	Passed

SHA-256 / ce09323f1804bbda3345e80b7221636a9b9f0c7db10adcf8a7cd2397a6d0a86c

Verification & scope

Deterministic simplified range service, with stipulated local policies and already parsed trusted inputs; not a complete HTTP implementation. 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 2026-09-29T14:41:15.843679+00:00.

Case digest / f0c7e678544df95b0a6afee6bdbb600eccca8177e8be6f3c5659830fad4dfbbf