FA-26461 / HTTP ranges / Open access

Every part uses the selected representation media type · case 01

Every part uses the selected representation media type.

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

ROOT CAUSE

The multipart-part-type-preserved decision uses return ["multipart/byteranges"]*count.

VERIFIED REPAIR

Apply the bounded decision exactly: return [object_type]*count

Unsuccessful approach: The partial repair uses return [object_type.split(";")[0]]*count, which still violates the stated contract.

Case contract

Return one Content-Type value per part, preserving the full selected object type including parameters.

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(object_type, count):
    return ["multipart/byteranges"]*count
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('multipart-part-type-preserved fixture 0', solve("text/plain; charset=utf-8",N), ["text/plain; charset=utf-8"]*N)
check('multipart-part-type-preserved fixture 1', solve("image/png",2), ["image/png","image/png"])
check('multipart-part-type-preserved fixture 2', solve("text/plain",0), [])
check('multipart-part-type-preserved fixture 3', solve("application/x; a=b",2), ["application/x; a=b"]*2)
check('multipart-part-type-preserved fixture 4', solve("x/y",1), ["x/y"])
check('multipart-part-type-preserved fixture 5', solve("",1), [""])
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-type-preserved fixture 0	`['multipart/byteranges']`	`['text/plain; charset=utf-8']`	Failed
multipart-part-type-preserved fixture 1	`['multipart/byteranges', 'multipart/byteranges']`	`['image/png', 'image/png']`	Failed
multipart-part-type-preserved fixture 2	`[]`	`[]`	Passed
multipart-part-type-preserved fixture 3	`['multipart/byteranges', 'multipart/byteranges']`	`['application/x; a=b', 'application/x; a=b']`	Failed
multipart-part-type-preserved fixture 4	`['multipart/byteranges']`	`['x/y']`	Failed
multipart-part-type-preserved fixture 5	`['multipart/byteranges']`	`['']`	Failed

SHA-256 / 3331606780056ee632c836e49a31ad59db4588ef49ae7b4d2637c475aa3a4bb3

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(object_type, count):
    return [object_type.split(";")[0]]*count
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('multipart-part-type-preserved fixture 0', solve("text/plain; charset=utf-8",N), ["text/plain; charset=utf-8"]*N)
check('multipart-part-type-preserved fixture 1', solve("image/png",2), ["image/png","image/png"])
check('multipart-part-type-preserved fixture 2', solve("text/plain",0), [])
check('multipart-part-type-preserved fixture 3', solve("application/x; a=b",2), ["application/x; a=b"]*2)
check('multipart-part-type-preserved fixture 4', solve("x/y",1), ["x/y"])
check('multipart-part-type-preserved fixture 5', solve("",1), [""])
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-type-preserved fixture 0	`['text/plain']`	`['text/plain; charset=utf-8']`	Failed
multipart-part-type-preserved fixture 1	`['image/png', 'image/png']`	`['image/png', 'image/png']`	Passed
multipart-part-type-preserved fixture 2	`[]`	`[]`	Passed
multipart-part-type-preserved fixture 3	`['application/x', 'application/x']`	`['application/x; a=b', 'application/x; a=b']`	Failed
multipart-part-type-preserved fixture 4	`['x/y']`	`['x/y']`	Passed
multipart-part-type-preserved fixture 5	`['']`	`['']`	Passed

SHA-256 / 689ca49f2560d133d178c0f5533ee4239551da69b77b52c7631110edf7442a1e

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(object_type, count):
    return [object_type]*count
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('multipart-part-type-preserved fixture 0', solve("text/plain; charset=utf-8",N), ["text/plain; charset=utf-8"]*N)
check('multipart-part-type-preserved fixture 1', solve("image/png",2), ["image/png","image/png"])
check('multipart-part-type-preserved fixture 2', solve("text/plain",0), [])
check('multipart-part-type-preserved fixture 3', solve("application/x; a=b",2), ["application/x; a=b"]*2)
check('multipart-part-type-preserved fixture 4', solve("x/y",1), ["x/y"])
check('multipart-part-type-preserved fixture 5', solve("",1), [""])
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-type-preserved fixture 0	`['text/plain; charset=utf-8']`	`['text/plain; charset=utf-8']`	Passed
multipart-part-type-preserved fixture 1	`['image/png', 'image/png']`	`['image/png', 'image/png']`	Passed
multipart-part-type-preserved fixture 2	`[]`	`[]`	Passed
multipart-part-type-preserved fixture 3	`['application/x; a=b', 'application/x; a=b']`	`['application/x; a=b', 'application/x; a=b']`	Passed
multipart-part-type-preserved fixture 4	`['x/y']`	`['x/y']`	Passed
multipart-part-type-preserved fixture 5	`['']`	`['']`	Passed

SHA-256 / 8ff051dfbfcd6299f0043d9788d86ee355975bac3bc5d481575e8a8ad8f84c45

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 2026-09-29T14:41:16.272339+00:00.

Case digest / 60be6b7d29e0f0a6704224342ad046a922d094d0041fea9c874e4780fd70264e