FA-26456 / HTTP ranges / Open access
Multipart response type carries a boundary rather than the object media type · case 01
Multipart response type carries a boundary rather than the object media type.
ROOT CAUSE
The multipart-top-content-type decision uses return object_type.
THE FAILURE
The multipart-top-content-type decision uses return object_type.
Unsuccessful approach: The partial repair uses return "multipart/byteranges", which still violates the stated contract.
Case contract
Return the stipulated ASCII top-level type multipart/byteranges; boundary="value". Boundary has only letters/digits and may be empty in this framing-unit test.
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(boundary, object_type):
return object_type
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('multipart-top-content-type fixture 0', solve("b"+str(N),"text/plain"), "multipart/byteranges; boundary=\"b"+str(N)+"\"")
check('multipart-top-content-type fixture 1', solve("x","image/png"), 'multipart/byteranges; boundary="x"')
check('multipart-top-content-type fixture 2', solve("","x/y"), 'multipart/byteranges; boundary=""')
check('multipart-top-content-type fixture 3', solve("abc",""), 'multipart/byteranges; boundary="abc"')
check('multipart-top-content-type fixture 4', solve("Z","application/octet-stream"), 'multipart/byteranges; boundary="Z"')
check('multipart-top-content-type fixture 5', solve("ab12","text/plain"), 'multipart/byteranges; boundary="ab12"')
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-top-content-type fixture 0 | text/plain | multipart/byteranges; boundary="b1" | Failed |
| multipart-top-content-type fixture 1 | image/png | multipart/byteranges; boundary="x" | Failed |
| multipart-top-content-type fixture 2 | x/y | multipart/byteranges; boundary="" | Failed |
| multipart-top-content-type fixture 3 | | multipart/byteranges; boundary="abc" | Failed |
| multipart-top-content-type fixture 4 | application/octet-stream | multipart/byteranges; boundary="Z" | Failed |
| multipart-top-content-type fixture 5 | text/plain | multipart/byteranges; boundary="ab12" | Failed |
SHA-256 / 33f075e5d44f5832b89ec93ec3116885206e6dc9196485604016c4ba53ec1e22
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(boundary, object_type):
return "multipart/byteranges"
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('multipart-top-content-type fixture 0', solve("b"+str(N),"text/plain"), "multipart/byteranges; boundary=\"b"+str(N)+"\"")
check('multipart-top-content-type fixture 1', solve("x","image/png"), 'multipart/byteranges; boundary="x"')
check('multipart-top-content-type fixture 2', solve("","x/y"), 'multipart/byteranges; boundary=""')
check('multipart-top-content-type fixture 3', solve("abc",""), 'multipart/byteranges; boundary="abc"')
check('multipart-top-content-type fixture 4', solve("Z","application/octet-stream"), 'multipart/byteranges; boundary="Z"')
check('multipart-top-content-type fixture 5', solve("ab12","text/plain"), 'multipart/byteranges; boundary="ab12"')
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-top-content-type fixture 0 | multipart/byteranges | multipart/byteranges; boundary="b1" | Failed |
| multipart-top-content-type fixture 1 | multipart/byteranges | multipart/byteranges; boundary="x" | Failed |
| multipart-top-content-type fixture 2 | multipart/byteranges | multipart/byteranges; boundary="" | Failed |
| multipart-top-content-type fixture 3 | multipart/byteranges | multipart/byteranges; boundary="abc" | Failed |
| multipart-top-content-type fixture 4 | multipart/byteranges | multipart/byteranges; boundary="Z" | Failed |
| multipart-top-content-type fixture 5 | multipart/byteranges | multipart/byteranges; boundary="ab12" | Failed |
SHA-256 / e6f03a9c2f0f5b8ddd311cf51af46a1489e49f917a1f74cded29db52b76402ad
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.
Sign in to the archive ↗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 2026-09-29T14:41:16.253557+00:00.
Case digest / 6ed10667287d7590707f27f7c0feea777b938d9d91bfbf98f20aaa99caba1227