FA-26521 / HTTP ranges / Open access

User-specific partial objects remain partitioned by principal · case 01

User-specific partial objects remain partitioned by principal.

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

ROOT CAUSE

The cache-private-partition decision uses return [url,validator,None].

VERIFIED REPAIR

Apply the bounded decision exactly: return [url,validator,principal if private else None]

Unsuccessful approach: The partial repair uses return [url,validator,principal or None], which still violates the stated contract.

Case contract

Return cache identity [url,validator,principal-or-null]; principal participates only for private responses, including empty principal.

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(url, private, principal, validator):
    return [url,validator,None]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('cache-private-partition fixture 0', solve("/x",True,"u"+str(N),"v"), ["/x","v","u"+str(N)])
check('cache-private-partition fixture 1', solve("/x",True,"","v"), ["/x","v",""])
check('cache-private-partition fixture 2', solve("/x",False,"u","v"), ["/x","v",None])
check('cache-private-partition fixture 3', solve("/y",False,"","w"), ["/y","w",None])
check('cache-private-partition fixture 4', solve("/x",True,"a","w"), ["/x","w","a"])
check('cache-private-partition fixture 5', solve("/x",True,"b","w"), ["/x","w","b"])
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
cache-private-partition fixture 0	`['/x', 'v', None]`	`['/x', 'v', 'u1']`	Failed
cache-private-partition fixture 1	`['/x', 'v', None]`	`['/x', 'v', '']`	Failed
cache-private-partition fixture 2	`['/x', 'v', None]`	`['/x', 'v', None]`	Passed
cache-private-partition fixture 3	`['/y', 'w', None]`	`['/y', 'w', None]`	Passed
cache-private-partition fixture 4	`['/x', 'w', None]`	`['/x', 'w', 'a']`	Failed
cache-private-partition fixture 5	`['/x', 'w', None]`	`['/x', 'w', 'b']`	Failed

SHA-256 / 7beedb5e944bc0c6a46ebe1dbced75220840475c8c044b19837197b5454dcabb

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(url, private, principal, validator):
    return [url,validator,principal or None]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('cache-private-partition fixture 0', solve("/x",True,"u"+str(N),"v"), ["/x","v","u"+str(N)])
check('cache-private-partition fixture 1', solve("/x",True,"","v"), ["/x","v",""])
check('cache-private-partition fixture 2', solve("/x",False,"u","v"), ["/x","v",None])
check('cache-private-partition fixture 3', solve("/y",False,"","w"), ["/y","w",None])
check('cache-private-partition fixture 4', solve("/x",True,"a","w"), ["/x","w","a"])
check('cache-private-partition fixture 5', solve("/x",True,"b","w"), ["/x","w","b"])
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
cache-private-partition fixture 0	`['/x', 'v', 'u1']`	`['/x', 'v', 'u1']`	Passed
cache-private-partition fixture 1	`['/x', 'v', None]`	`['/x', 'v', '']`	Failed
cache-private-partition fixture 2	`['/x', 'v', 'u']`	`['/x', 'v', None]`	Failed
cache-private-partition fixture 3	`['/y', 'w', None]`	`['/y', 'w', None]`	Passed
cache-private-partition fixture 4	`['/x', 'w', 'a']`	`['/x', 'w', 'a']`	Passed
cache-private-partition fixture 5	`['/x', 'w', 'b']`	`['/x', 'w', 'b']`	Passed

SHA-256 / 4b6e0a20c7c192cae2460c2d10b24cd07146eeeb81fbfa697a57bb0c9a6afb44

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(url, private, principal, validator):
    return [url,validator,principal if private else None]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('cache-private-partition fixture 0', solve("/x",True,"u"+str(N),"v"), ["/x","v","u"+str(N)])
check('cache-private-partition fixture 1', solve("/x",True,"","v"), ["/x","v",""])
check('cache-private-partition fixture 2', solve("/x",False,"u","v"), ["/x","v",None])
check('cache-private-partition fixture 3', solve("/y",False,"","w"), ["/y","w",None])
check('cache-private-partition fixture 4', solve("/x",True,"a","w"), ["/x","w","a"])
check('cache-private-partition fixture 5', solve("/x",True,"b","w"), ["/x","w","b"])
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
cache-private-partition fixture 0	`['/x', 'v', 'u1']`	`['/x', 'v', 'u1']`	Passed
cache-private-partition fixture 1	`['/x', 'v', '']`	`['/x', 'v', '']`	Passed
cache-private-partition fixture 2	`['/x', 'v', None]`	`['/x', 'v', None]`	Passed
cache-private-partition fixture 3	`['/y', 'w', None]`	`['/y', 'w', None]`	Passed
cache-private-partition fixture 4	`['/x', 'w', 'a']`	`['/x', 'w', 'a']`	Passed
cache-private-partition fixture 5	`['/x', 'w', 'b']`	`['/x', 'w', 'b']`	Passed

SHA-256 / 432a497c47cf0a9882ae1a84d672f44494c8b0a45d28434ca39769b20f079042

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 2026-09-29T14:41:16.816019+00:00.

Case digest / d00b7e478ebd5c99140451515f1254925b64a4cf3037f21cf49a884951d55173