FA-11131 / Streaming segment lifecycle / Open access

Implicit range offset resource scope · case 01

An omitted range offset carries over from an unrelated resource URI.

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

ROOT CAUSE

An omitted range offset carries over from an unrelated resource URI.

THE FAILURE

An omitted range offset carries over from an unrelated resource URI.

Unsuccessful approach: Using truthiness discards an explicitly specified zero offset.

Case contract

Resolve byte-range offset under this explicit local policy: explicit offset wins including zero; omitted offset follows prior range only for same URI, otherwise starts at zero. Not a complete manifest validator.

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(previous, uri, length, explicit):
    return [uri,explicit if explicit is not None else (previous[1]+previous[2] if previous else 0),length]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*(['a', 10, 5], 'b', 3, None)),['b', 0, 3])
check('fixture 2',solve(*(['a', 10, 5], 'a', 3, None)),['a', 15, 3])
check('fixture 3',solve(*(['a', 10, 5], 'a', 3, 0)),['a', 0, 3])
check('fixture 4',solve(*(None, 'a', 2, None)),['a', 0, 2])
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	`['b', 15, 3]`	`['b', 0, 3]`	Failed
fixture 2	`['a', 15, 3]`	`['a', 15, 3]`	Passed
fixture 3	`['a', 0, 3]`	`['a', 0, 3]`	Passed
fixture 4	`['a', 0, 2]`	`['a', 0, 2]`	Passed

SHA-256 / 9883cb0d5a2c3054390eda22b5e54d0d333d664400864f55af04ec52174e2f15

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(previous, uri, length, explicit):
    return [uri,explicit or (previous[1]+previous[2] if previous and previous[0]==uri else 0),length]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*(['a', 10, 5], 'b', 3, None)),['b', 0, 3])
check('fixture 2',solve(*(['a', 10, 5], 'a', 3, None)),['a', 15, 3])
check('fixture 3',solve(*(['a', 10, 5], 'a', 3, 0)),['a', 0, 3])
check('fixture 4',solve(*(None, 'a', 2, None)),['a', 0, 2])
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	`['b', 0, 3]`	`['b', 0, 3]`	Passed
fixture 2	`['a', 15, 3]`	`['a', 15, 3]`	Passed
fixture 3	`['a', 15, 3]`	`['a', 0, 3]`	Failed
fixture 4	`['a', 0, 2]`	`['a', 0, 2]`	Passed

SHA-256 / ced5260293c93848f46ea2b5e920262c9b824b400b2558a362ed0fd865d5cfd5

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 4 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.

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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 2026-09-29T14:38:45.231343+00:00.

Case digest / b1ba26eb66017ca11898bf3afb0027553bdbe1dbd085200fe948f954ae69a735