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FA-26571 / HTTP ranges / Open access

Canceled range streams release snapshot pins and pending data · case 01

Canceled range streams release snapshot pins and pending data.

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

ROOT CAUSE

The stream-cancel-releases-pin decision uses return [pins,""] if cancelled else [pins,pending].

VERIFIED REPAIR

Apply the bounded decision exactly: return [0,""] if cancelled else [pins,pending]

Unsuccessful approach: The partial repair uses return [0,pending] if cancelled else [pins,pending], which still violates the stated contract.

Case contract

pins is the current stream-owned count (0 or1); cancellation clears both pin and pending body, otherwise preserves state.

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(cancelled, pins, pending):
    return [pins,""] if cancelled else [pins,pending]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('stream-cancel-releases-pin fixture 0', solve(True,1,"p"*N), [0,""])
check('stream-cancel-releases-pin fixture 1', solve(True,0,"p"), [0,""])
check('stream-cancel-releases-pin fixture 2', solve(True,1,""), [0,""])
check('stream-cancel-releases-pin fixture 3', solve(False,1,"p"*N), [1,"p"*N])
check('stream-cancel-releases-pin fixture 4', solve(False,0,""), [0,""])
check('stream-cancel-releases-pin fixture 5', solve(False,0,"p"), [0,"p"])
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
stream-cancel-releases-pin fixture 0[1, ''][0, '']Failed
stream-cancel-releases-pin fixture 1[0, ''][0, '']Passed
stream-cancel-releases-pin fixture 2[1, ''][0, '']Failed
stream-cancel-releases-pin fixture 3[1, 'p'][1, 'p']Passed
stream-cancel-releases-pin fixture 4[0, ''][0, '']Passed
stream-cancel-releases-pin fixture 5[0, 'p'][0, 'p']Passed

SHA-256 / 86fdc67ed75f7b32311e3968e4488a053e03208d3bb2f004d61fb34ac061e25e

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(cancelled, pins, pending):
    return [0,pending] if cancelled else [pins,pending]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('stream-cancel-releases-pin fixture 0', solve(True,1,"p"*N), [0,""])
check('stream-cancel-releases-pin fixture 1', solve(True,0,"p"), [0,""])
check('stream-cancel-releases-pin fixture 2', solve(True,1,""), [0,""])
check('stream-cancel-releases-pin fixture 3', solve(False,1,"p"*N), [1,"p"*N])
check('stream-cancel-releases-pin fixture 4', solve(False,0,""), [0,""])
check('stream-cancel-releases-pin fixture 5', solve(False,0,"p"), [0,"p"])
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
stream-cancel-releases-pin fixture 0[0, 'p'][0, '']Failed
stream-cancel-releases-pin fixture 1[0, 'p'][0, '']Failed
stream-cancel-releases-pin fixture 2[0, ''][0, '']Passed
stream-cancel-releases-pin fixture 3[1, 'p'][1, 'p']Passed
stream-cancel-releases-pin fixture 4[0, ''][0, '']Passed
stream-cancel-releases-pin fixture 5[0, 'p'][0, 'p']Passed

SHA-256 / 2e81bc62751d3e0f69d882c6de84ff3183da24e4d2774ab3751afda43a65c7ea

3 / The verified repair

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

N = 1
observations = []
def solve(cancelled, pins, pending):
    return [0,""] if cancelled else [pins,pending]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('stream-cancel-releases-pin fixture 0', solve(True,1,"p"*N), [0,""])
check('stream-cancel-releases-pin fixture 1', solve(True,0,"p"), [0,""])
check('stream-cancel-releases-pin fixture 2', solve(True,1,""), [0,""])
check('stream-cancel-releases-pin fixture 3', solve(False,1,"p"*N), [1,"p"*N])
check('stream-cancel-releases-pin fixture 4', solve(False,0,""), [0,""])
check('stream-cancel-releases-pin fixture 5', solve(False,0,"p"), [0,"p"])
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
stream-cancel-releases-pin fixture 0[0, ''][0, '']Passed
stream-cancel-releases-pin fixture 1[0, ''][0, '']Passed
stream-cancel-releases-pin fixture 2[0, ''][0, '']Passed
stream-cancel-releases-pin fixture 3[1, 'p'][1, 'p']Passed
stream-cancel-releases-pin fixture 4[0, ''][0, '']Passed
stream-cancel-releases-pin fixture 5[0, 'p'][0, 'p']Passed

SHA-256 / c9a04afdf4bca7f917c5e5b6ab69d9c45c3403598da458589dca6787e9159f25

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 2026-09-29T14:41:17.184978+00:00.

Case digest / 7f844c7fc2eef490596c36334feded9f6518549e3ddf73f313acf8708d4052a6