FAILURE MAP
← Case archive

FA-26526 / HTTP ranges / Open access

A wildcard Vary response is not stored as a reusable partial object · case 01

A wildcard Vary response is not stored as a reusable partial object.

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

ROOT CAUSE

The cache-vary-star-bypass decision uses return ["store",payload].

VERIFIED REPAIR

Apply the bounded decision exactly: return ["bypass",""] if any(v.strip()=="*" for v in vary) else ["store",payload]

Unsuccessful approach: The partial repair uses return ["bypass",""] if vary==["*"] else ["store",payload], which still violates the stated contract.

Case contract

Return [store,payload] unless parsed Vary tokens include *, then [bypass,empty]. Tokens may have surrounding ASCII space.

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(vary, payload):
    return ["store",payload]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('cache-vary-star-bypass fixture 0', solve( ["accept-encoding","*"],"p"*N), ["bypass",""])
check('cache-vary-star-bypass fixture 1', solve([" * "],"p"), ["bypass",""])
check('cache-vary-star-bypass fixture 2', solve(["*"],"p"), ["bypass",""])
check('cache-vary-star-bypass fixture 3', solve([],"p"*N), ["store","p"*N])
check('cache-vary-star-bypass fixture 4', solve(["x-star"],"p"), ["store","p"])
check('cache-vary-star-bypass fixture 5', solve(["accept-language"],""), ["store",""])
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
cache-vary-star-bypass fixture 0['store', 'p']['bypass', '']Failed
cache-vary-star-bypass fixture 1['store', 'p']['bypass', '']Failed
cache-vary-star-bypass fixture 2['store', 'p']['bypass', '']Failed
cache-vary-star-bypass fixture 3['store', 'p']['store', 'p']Passed
cache-vary-star-bypass fixture 4['store', 'p']['store', 'p']Passed
cache-vary-star-bypass fixture 5['store', '']['store', '']Passed

SHA-256 / 7010bc2a6e89e1b5f57af3de67e3b06291ac629dabf5216629aa47c605c82604

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(vary, payload):
    return ["bypass",""] if vary==["*"] else ["store",payload]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('cache-vary-star-bypass fixture 0', solve( ["accept-encoding","*"],"p"*N), ["bypass",""])
check('cache-vary-star-bypass fixture 1', solve([" * "],"p"), ["bypass",""])
check('cache-vary-star-bypass fixture 2', solve(["*"],"p"), ["bypass",""])
check('cache-vary-star-bypass fixture 3', solve([],"p"*N), ["store","p"*N])
check('cache-vary-star-bypass fixture 4', solve(["x-star"],"p"), ["store","p"])
check('cache-vary-star-bypass fixture 5', solve(["accept-language"],""), ["store",""])
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
cache-vary-star-bypass fixture 0['store', 'p']['bypass', '']Failed
cache-vary-star-bypass fixture 1['store', 'p']['bypass', '']Failed
cache-vary-star-bypass fixture 2['bypass', '']['bypass', '']Passed
cache-vary-star-bypass fixture 3['store', 'p']['store', 'p']Passed
cache-vary-star-bypass fixture 4['store', 'p']['store', 'p']Passed
cache-vary-star-bypass fixture 5['store', '']['store', '']Passed

SHA-256 / 9d6e426a77cfb57d68690eac27272843d79760256c52b1e1d201746f12761817

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(vary, payload):
    return ["bypass",""] if any(v.strip()=="*" for v in vary) else ["store",payload]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('cache-vary-star-bypass fixture 0', solve( ["accept-encoding","*"],"p"*N), ["bypass",""])
check('cache-vary-star-bypass fixture 1', solve([" * "],"p"), ["bypass",""])
check('cache-vary-star-bypass fixture 2', solve(["*"],"p"), ["bypass",""])
check('cache-vary-star-bypass fixture 3', solve([],"p"*N), ["store","p"*N])
check('cache-vary-star-bypass fixture 4', solve(["x-star"],"p"), ["store","p"])
check('cache-vary-star-bypass fixture 5', solve(["accept-language"],""), ["store",""])
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
cache-vary-star-bypass fixture 0['bypass', '']['bypass', '']Passed
cache-vary-star-bypass fixture 1['bypass', '']['bypass', '']Passed
cache-vary-star-bypass fixture 2['bypass', '']['bypass', '']Passed
cache-vary-star-bypass fixture 3['store', 'p']['store', 'p']Passed
cache-vary-star-bypass fixture 4['store', 'p']['store', 'p']Passed
cache-vary-star-bypass fixture 5['store', '']['store', '']Passed

SHA-256 / 565643ab08173a411583e14f75dc5b37f64eb7d705dddd825a8f9d415f5f9639

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 2026-09-29T14:41:16.852634+00:00.

Case digest / 4b163d84a0e00a0ae0c8c1d5579baa97b65ea304c7166bfee6a99740eda0621e