FA-26536 / HTTP ranges / Open access

No-store metadata prevents partial staging from surviving admission · case 01

No-store metadata prevents partial staging from surviving admission.

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

ROOT CAUSE

The cache-no-store-purges-staging decision uses return [staged,committed].

THE FAILURE

The cache-no-store-purges-staging decision uses return [staged,committed].

Unsuccessful approach: The partial repair uses return [staged,""] if no_store else [staged,committed], which still violates the stated contract.

Case contract

Return [staged,committed] unchanged for reusable responses; no-store clears both temporary and committed bytes for this object.

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(no_store, staged, committed):
    return [staged,committed]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('cache-no-store-purges-staging fixture 0', solve(True,"s"*N,"c"*N), ["",""])
check('cache-no-store-purges-staging fixture 1', solve(True,"s",""), ["",""])
check('cache-no-store-purges-staging fixture 2', solve(True,"","c"), ["",""])
check('cache-no-store-purges-staging fixture 3', solve(False,"s"*N,"c"), ["s"*N,"c"])
check('cache-no-store-purges-staging fixture 4', solve(False,"",""), ["",""])
check('cache-no-store-purges-staging fixture 5', solve(False,"s",""), ["s",""])
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-no-store-purges-staging fixture 0	`['s', 'c']`	`['', '']`	Failed
cache-no-store-purges-staging fixture 1	`['s', '']`	`['', '']`	Failed
cache-no-store-purges-staging fixture 2	`['', 'c']`	`['', '']`	Failed
cache-no-store-purges-staging fixture 3	`['s', 'c']`	`['s', 'c']`	Passed
cache-no-store-purges-staging fixture 4	`['', '']`	`['', '']`	Passed
cache-no-store-purges-staging fixture 5	`['s', '']`	`['s', '']`	Passed

SHA-256 / 67d9c12f3d59e0d6bd8e411ade6b5ebf587de48f758a4c22e2d7d83d10bd06eb

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(no_store, staged, committed):
    return [staged,""] if no_store else [staged,committed]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('cache-no-store-purges-staging fixture 0', solve(True,"s"*N,"c"*N), ["",""])
check('cache-no-store-purges-staging fixture 1', solve(True,"s",""), ["",""])
check('cache-no-store-purges-staging fixture 2', solve(True,"","c"), ["",""])
check('cache-no-store-purges-staging fixture 3', solve(False,"s"*N,"c"), ["s"*N,"c"])
check('cache-no-store-purges-staging fixture 4', solve(False,"",""), ["",""])
check('cache-no-store-purges-staging fixture 5', solve(False,"s",""), ["s",""])
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-no-store-purges-staging fixture 0	`['s', '']`	`['', '']`	Failed
cache-no-store-purges-staging fixture 1	`['s', '']`	`['', '']`	Failed
cache-no-store-purges-staging fixture 2	`['', '']`	`['', '']`	Passed
cache-no-store-purges-staging fixture 3	`['s', 'c']`	`['s', 'c']`	Passed
cache-no-store-purges-staging fixture 4	`['', '']`	`['', '']`	Passed
cache-no-store-purges-staging fixture 5	`['s', '']`	`['s', '']`	Passed

SHA-256 / 1de97b5b466908444cc56142ad9b3ee9d0c0b4d7a43b5ffe31582a137079d9dd

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.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

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 2026-09-29T14:41:16.906420+00:00.

Case digest / 80e76b0a64a654a59403a1fda45ddc7b25015ede89b1de5687a03ff1979460ec