FA-11126 / Streaming segment lifecycle / Open access

Segment byte range inclusive header · case 01

Adding full byte length fetches one byte from the following range.

Verified by executionVariant 1 · 4 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Adding full byte length fetches one byte from the following range.

VERIFIED REPAIR

Preserve the media contract: Convert nonnegative byte offset/length metadata to an inclusive request range; zero length produces no request.

Unsuccessful approach: The ending byte is computed without adding the resource offset.

Case contract

Convert nonnegative byte offset/length metadata to an inclusive request range; zero length produces no request.

Why this case matters

A deterministic local media controller stage; metadata and downloaded data are supplied explicitly. No external player, service or codec is required.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(offset, length):
    return [offset,offset+length]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*(10, 5)),[10, 14])
check('fixture 2',solve(*(0, 1)),[0, 0])
check('fixture 3',solve(*(7, 0)),None)
check('fixture 4',solve(*(100, 2)),[100, 101])
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
fixture 1	`[10, 15]`	`[10, 14]`	Failed
fixture 2	`[0, 1]`	`[0, 0]`	Failed
fixture 3	`[7, 7]`	`None`	Failed
fixture 4	`[100, 102]`	`[100, 101]`	Failed

SHA-256 / 516505456a346737b116c17ea4be69395a9e3c41508ab61edfa766f2ea0663a7

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(offset, length):
    return [offset,length-1] if length else None
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*(10, 5)),[10, 14])
check('fixture 2',solve(*(0, 1)),[0, 0])
check('fixture 3',solve(*(7, 0)),None)
check('fixture 4',solve(*(100, 2)),[100, 101])
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
fixture 1	`[10, 4]`	`[10, 14]`	Failed
fixture 2	`[0, 0]`	`[0, 0]`	Passed
fixture 3	`None`	`None`	Passed
fixture 4	`[100, 1]`	`[100, 101]`	Failed

SHA-256 / afec4ac76867c6685806a1331f46fb82da91dc2c585a8be6760db6dd33917899

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(offset, length):
    return [offset,offset+length-1] if length else None
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*(10, 5)),[10, 14])
check('fixture 2',solve(*(0, 1)),[0, 0])
check('fixture 3',solve(*(7, 0)),None)
check('fixture 4',solve(*(100, 2)),[100, 101])
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
fixture 1	`[10, 14]`	`[10, 14]`	Passed
fixture 2	`[0, 0]`	`[0, 0]`	Passed
fixture 3	`None`	`None`	Passed
fixture 4	`[100, 101]`	`[100, 101]`	Passed

SHA-256 / 09989de559ac9cc7c422e2da1a113d1e2982759ec7f3e0b28c01dcb25f510a63

Verification & scope

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 2026-09-29T14:38:45.194033+00:00.

Case digest / 816bacd041f6cd05d74711284ef3b9537e8f677e7e51ada592c1e61d6cbb97a2