FA-26476 / HTTP ranges / Open access

Multipart assembly preserves the normalized request order · case 01

Multipart assembly preserves the normalized request order.

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

ROOT CAUSE

The multipart-part-order decision uses return [p[2] for p in sorted(parts,key=lambda p:p[1])].

THE FAILURE

The multipart-part-order decision uses return [p[2] for p in sorted(parts,key=lambda p:p[1])].

Unsuccessful approach: The partial repair uses return [p[2] for p in parts], which still violates the stated contract.

Case contract

Parts are [request-position,absolute-start,payload]. Return payloads ordered by request-position, not by byte offset or arrival order. Positions unique.

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(parts):
    return [p[2] for p in sorted(parts,key=lambda p:p[1])]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('multipart-part-order fixture 0', solve([[1,0,"b"],[0,N,"a"]]), ["a","b"])
check('multipart-part-order fixture 1', solve([[0,N,"a"],[1,0,"b"]]), ["a","b"])
check('multipart-part-order fixture 2', solve([]), [])
check('multipart-part-order fixture 3', solve([[0,0,"x"*N]]), ["x"*N])
check('multipart-part-order fixture 4', solve([[2,0,"c"],[0,0,"a"],[1,0,"b"]]), ["a","b","c"])
check('multipart-part-order fixture 5', solve([[0,0,""],[1,1,"b"]]), ["","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
multipart-part-order fixture 0	`['b', 'a']`	`['a', 'b']`	Failed
multipart-part-order fixture 1	`['b', 'a']`	`['a', 'b']`	Failed
multipart-part-order fixture 2	`[]`	`[]`	Passed
multipart-part-order fixture 3	`['x']`	`['x']`	Passed
multipart-part-order fixture 4	`['c', 'a', 'b']`	`['a', 'b', 'c']`	Failed
multipart-part-order fixture 5	`['', 'b']`	`['', 'b']`	Passed

SHA-256 / c0d8682efe91002eba278fec08673d597977421e04e375b2aa2adb645692b768

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(parts):
    return [p[2] for p in parts]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('multipart-part-order fixture 0', solve([[1,0,"b"],[0,N,"a"]]), ["a","b"])
check('multipart-part-order fixture 1', solve([[0,N,"a"],[1,0,"b"]]), ["a","b"])
check('multipart-part-order fixture 2', solve([]), [])
check('multipart-part-order fixture 3', solve([[0,0,"x"*N]]), ["x"*N])
check('multipart-part-order fixture 4', solve([[2,0,"c"],[0,0,"a"],[1,0,"b"]]), ["a","b","c"])
check('multipart-part-order fixture 5', solve([[0,0,""],[1,1,"b"]]), ["","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
multipart-part-order fixture 0	`['b', 'a']`	`['a', 'b']`	Failed
multipart-part-order fixture 1	`['a', 'b']`	`['a', 'b']`	Passed
multipart-part-order fixture 2	`[]`	`[]`	Passed
multipart-part-order fixture 3	`['x']`	`['x']`	Passed
multipart-part-order fixture 4	`['c', 'a', 'b']`	`['a', 'b', 'c']`	Failed
multipart-part-order fixture 5	`['', 'b']`	`['', 'b']`	Passed

SHA-256 / a5132a29d38280ddaf4397543471c5bc21f4736a0e7c49fac7580b2f26c21bf5

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 2026-09-29T14:41:16.316017+00:00.

Case digest / 84351e1f9ad59be4d4a297b9cd13d6bc14b0cf9326975e6ac01c141c0104249b