FA-26641 / HTTP ranges / Open access

Repeated Range fields combine their member lists under one unit · case 01

Repeated Range fields combine their member lists under one unit.

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

ROOT CAUSE

The range-field-combination decision uses return fields[0] if fields else None.

VERIFIED REPAIR

Apply the bounded decision exactly: return [fields[0][0],[m for u,ms in fields for m in ms]] if fields and all(u==fields[0][0] for u,ms in fields) else None

Unsuccessful approach: The partial repair uses return [fields[0][0],[m for u,ms in fields for m in ms]] if fields else None, which still violates the stated contract.

Case contract

Parsed fields are [unit,members]. Return [unit,joined-members] when every unit matches first; mixed units return None; no fields returns None. Units already normalized.

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(fields):
    return fields[0] if fields else None
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('range-field-combination fixture 0', solve([["bytes",["0-"+str(N)]],["bytes",["8-9"]]]), ["bytes",["0-"+str(N),"8-9"]])
check('range-field-combination fixture 1', solve([["bytes",["0-1"]],["items",["2-3"]]]), None)
check('range-field-combination fixture 2', solve([]), None)
check('range-field-combination fixture 3', solve([["bytes",["0-1"]]]), ["bytes",["0-1"]])
check('range-field-combination fixture 4', solve([["items",["a"]],["items",["b"]]]), ["items",["a","b"]])
check('range-field-combination fixture 5', solve([["bytes",[]],["bytes",["0-0"]]]), ["bytes",["0-0"]])
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
range-field-combination fixture 0	`['bytes', ['0-1']]`	`['bytes', ['0-1', '8-9']]`	Failed
range-field-combination fixture 1	`['bytes', ['0-1']]`	`None`	Failed
range-field-combination fixture 2	`None`	`None`	Passed
range-field-combination fixture 3	`['bytes', ['0-1']]`	`['bytes', ['0-1']]`	Passed
range-field-combination fixture 4	`['items', ['a']]`	`['items', ['a', 'b']]`	Failed
range-field-combination fixture 5	`['bytes', []]`	`['bytes', ['0-0']]`	Failed

SHA-256 / f1f62d00f897f9c6532d03633f71d177a9846da384d7186a4ed99fca3714cb6d

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(fields):
    return [fields[0][0],[m for u,ms in fields for m in ms]] if fields else None
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('range-field-combination fixture 0', solve([["bytes",["0-"+str(N)]],["bytes",["8-9"]]]), ["bytes",["0-"+str(N),"8-9"]])
check('range-field-combination fixture 1', solve([["bytes",["0-1"]],["items",["2-3"]]]), None)
check('range-field-combination fixture 2', solve([]), None)
check('range-field-combination fixture 3', solve([["bytes",["0-1"]]]), ["bytes",["0-1"]])
check('range-field-combination fixture 4', solve([["items",["a"]],["items",["b"]]]), ["items",["a","b"]])
check('range-field-combination fixture 5', solve([["bytes",[]],["bytes",["0-0"]]]), ["bytes",["0-0"]])
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
range-field-combination fixture 0	`['bytes', ['0-1', '8-9']]`	`['bytes', ['0-1', '8-9']]`	Passed
range-field-combination fixture 1	`['bytes', ['0-1', '2-3']]`	`None`	Failed
range-field-combination fixture 2	`None`	`None`	Passed
range-field-combination fixture 3	`['bytes', ['0-1']]`	`['bytes', ['0-1']]`	Passed
range-field-combination fixture 4	`['items', ['a', 'b']]`	`['items', ['a', 'b']]`	Passed
range-field-combination fixture 5	`['bytes', ['0-0']]`	`['bytes', ['0-0']]`	Passed

SHA-256 / c5427fc899540058bd221850a7f9f60842b3218b5c8d3caa7a0c3dfcff2752c4

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(fields):
    return [fields[0][0],[m for u,ms in fields for m in ms]] if fields and all(u==fields[0][0] for u,ms in fields) else None
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('range-field-combination fixture 0', solve([["bytes",["0-"+str(N)]],["bytes",["8-9"]]]), ["bytes",["0-"+str(N),"8-9"]])
check('range-field-combination fixture 1', solve([["bytes",["0-1"]],["items",["2-3"]]]), None)
check('range-field-combination fixture 2', solve([]), None)
check('range-field-combination fixture 3', solve([["bytes",["0-1"]]]), ["bytes",["0-1"]])
check('range-field-combination fixture 4', solve([["items",["a"]],["items",["b"]]]), ["items",["a","b"]])
check('range-field-combination fixture 5', solve([["bytes",[]],["bytes",["0-0"]]]), ["bytes",["0-0"]])
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
range-field-combination fixture 0	`['bytes', ['0-1', '8-9']]`	`['bytes', ['0-1', '8-9']]`	Passed
range-field-combination fixture 1	`None`	`None`	Passed
range-field-combination fixture 2	`None`	`None`	Passed
range-field-combination fixture 3	`['bytes', ['0-1']]`	`['bytes', ['0-1']]`	Passed
range-field-combination fixture 4	`['items', ['a', 'b']]`	`['items', ['a', 'b']]`	Passed
range-field-combination fixture 5	`['bytes', ['0-0']]`	`['bytes', ['0-0']]`	Passed

SHA-256 / 65863e794a8328facab23545472a22d1aa7745258db69db7fa9a1747cd831ef4

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 2026-09-29T14:41:17.815620+00:00.

Case digest / 65abeb1c8c42efa27fb08fdfb2388d85a976be542afc87e012d3455c3eb8a18b