FA-26736 / HTTP ranges / Open access

The representation length header does not collapse to the transferred fragment length · case 01

The representation length header does not collapse to the transferred fragment length.

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

ROOT CAUSE

The range-response-total-not-part-length decision uses return [part,part].

VERIFIED REPAIR

Apply the bounded decision exactly: return [part,whole]

Unsuccessful approach: The partial repair uses return [whole,whole], which still violates the stated contract.

Case contract

Return [Content-Length,complete-length] as [part,whole] for a prevalidated single range response.

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(whole, part):
    return [part,part]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('range-response-total-not-part-length fixture 0', solve(3*N,N), [N,3*N])
check('range-response-total-not-part-length fixture 1', solve(N,0), [0,N])
check('range-response-total-not-part-length fixture 2', solve(0,0), [0,0])
check('range-response-total-not-part-length fixture 3', solve(N,N), [N,N])
check('range-response-total-not-part-length fixture 4', solve(10,1), [1,10])
check('range-response-total-not-part-length fixture 5', solve(10,9), [9,10])
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-response-total-not-part-length fixture 0	`[1, 1]`	`[1, 3]`	Failed
range-response-total-not-part-length fixture 1	`[0, 0]`	`[0, 1]`	Failed
range-response-total-not-part-length fixture 2	`[0, 0]`	`[0, 0]`	Passed
range-response-total-not-part-length fixture 3	`[1, 1]`	`[1, 1]`	Passed
range-response-total-not-part-length fixture 4	`[1, 1]`	`[1, 10]`	Failed
range-response-total-not-part-length fixture 5	`[9, 9]`	`[9, 10]`	Failed

SHA-256 / 4c6ba737eb647e632e4ada03466615b2e9030ec956979a92247efefc4cc62a4c

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(whole, part):
    return [whole,whole]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('range-response-total-not-part-length fixture 0', solve(3*N,N), [N,3*N])
check('range-response-total-not-part-length fixture 1', solve(N,0), [0,N])
check('range-response-total-not-part-length fixture 2', solve(0,0), [0,0])
check('range-response-total-not-part-length fixture 3', solve(N,N), [N,N])
check('range-response-total-not-part-length fixture 4', solve(10,1), [1,10])
check('range-response-total-not-part-length fixture 5', solve(10,9), [9,10])
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-response-total-not-part-length fixture 0	`[3, 3]`	`[1, 3]`	Failed
range-response-total-not-part-length fixture 1	`[1, 1]`	`[0, 1]`	Failed
range-response-total-not-part-length fixture 2	`[0, 0]`	`[0, 0]`	Passed
range-response-total-not-part-length fixture 3	`[1, 1]`	`[1, 1]`	Passed
range-response-total-not-part-length fixture 4	`[10, 10]`	`[1, 10]`	Failed
range-response-total-not-part-length fixture 5	`[10, 10]`	`[9, 10]`	Failed

SHA-256 / f1a7ddd9eb8284d57bcc115af8eb623fcfa17b2a2c7f22f2fff3b0b36c95e4ba

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(whole, part):
    return [part,whole]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('range-response-total-not-part-length fixture 0', solve(3*N,N), [N,3*N])
check('range-response-total-not-part-length fixture 1', solve(N,0), [0,N])
check('range-response-total-not-part-length fixture 2', solve(0,0), [0,0])
check('range-response-total-not-part-length fixture 3', solve(N,N), [N,N])
check('range-response-total-not-part-length fixture 4', solve(10,1), [1,10])
check('range-response-total-not-part-length fixture 5', solve(10,9), [9,10])
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-response-total-not-part-length fixture 0	`[1, 3]`	`[1, 3]`	Passed
range-response-total-not-part-length fixture 1	`[0, 1]`	`[0, 1]`	Passed
range-response-total-not-part-length fixture 2	`[0, 0]`	`[0, 0]`	Passed
range-response-total-not-part-length fixture 3	`[1, 1]`	`[1, 1]`	Passed
range-response-total-not-part-length fixture 4	`[1, 10]`	`[1, 10]`	Passed
range-response-total-not-part-length fixture 5	`[9, 10]`	`[9, 10]`	Passed

SHA-256 / 088b5d884d0c3c2f695c1e8d41513a085f7902c115c8329de521cbc2483eea6c

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 2026-09-29T14:41:18.738126+00:00.

Case digest / ed64b4c04993135af4792f98655d205486115e4975345db6a8ba0739a26e4093