FA-10986 / Audio playback scheduling / Open access
Write ring wraparound · case 01
A contiguous write discards the portion crossing the ring end.
ROOT CAUSE
A contiguous write discards the portion crossing the ring end.
VERIFIED REPAIR
Apply the explicit PCM/playback contract: Write at most capacity incoming samples into a nonempty ring buffer at valid position, wrapping once and preserving unwritten slots.
Unsuccessful approach: Writing from buffer zero ignores the ring write cursor.
Case contract
Write at most capacity incoming samples into a nonempty ring buffer at valid position, wrapping once and preserving unwritten slots.
Why this case matters
A pure Python local audio pipeline stage with explicit sample formats and frame conventions; no real-time device or signal-spectrum claims.
1 / The failure
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(buffer, position, incoming):
return [incoming[i-position] if position<=i<position+len(incoming) else x for i,x in enumerate(buffer)]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*([0, 0, 0, 0], 3, [7, 8])),[8, 0, 0, 7])
check('fixture 2',solve(*([1, 2, 3], 1, [9])),[1, 9, 3])
check('fixture 3',solve(*([1, 2], 0, [])),[1, 2])
check('fixture 4',solve(*([0, 0], 0, [5, 6])),[5, 6])
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 | [0, 0, 0, 7] | [8, 0, 0, 7] | Failed |
| fixture 2 | [1, 9, 3] | [1, 9, 3] | Passed |
| fixture 3 | [1, 2] | [1, 2] | Passed |
| fixture 4 | [5, 6] | [5, 6] | Passed |
SHA-256 / 0c241b6c23ae6af3213a2e3e4ff5efbf8586c63217b98bf899ae9538d330a157
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(buffer, position, incoming):
return [incoming[i] if i<len(incoming) else x for i,x in enumerate(buffer)]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*([0, 0, 0, 0], 3, [7, 8])),[8, 0, 0, 7])
check('fixture 2',solve(*([1, 2, 3], 1, [9])),[1, 9, 3])
check('fixture 3',solve(*([1, 2], 0, [])),[1, 2])
check('fixture 4',solve(*([0, 0], 0, [5, 6])),[5, 6])
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 | [7, 8, 0, 0] | [8, 0, 0, 7] | Failed |
| fixture 2 | [9, 2, 3] | [1, 9, 3] | Failed |
| fixture 3 | [1, 2] | [1, 2] | Passed |
| fixture 4 | [5, 6] | [5, 6] | Passed |
SHA-256 / fbc48f68c2d570816d86b18b3002aa126ac29fa319520f0356f94543832fb114
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(buffer, position, incoming):
return [(incoming[(i-position)%len(buffer)] if (i-position)%len(buffer)<len(incoming) else x) for i,x in enumerate(buffer)]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*([0, 0, 0, 0], 3, [7, 8])),[8, 0, 0, 7])
check('fixture 2',solve(*([1, 2, 3], 1, [9])),[1, 9, 3])
check('fixture 3',solve(*([1, 2], 0, [])),[1, 2])
check('fixture 4',solve(*([0, 0], 0, [5, 6])),[5, 6])
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 | [8, 0, 0, 7] | [8, 0, 0, 7] | Passed |
| fixture 2 | [1, 9, 3] | [1, 9, 3] | Passed |
| fixture 3 | [1, 2] | [1, 2] | Passed |
| fixture 4 | [5, 6] | [5, 6] | Passed |
SHA-256 / 597084a256363b1f0f8c407012a06d787b8d77d0b60d434a1a322c4bbcbee6c3
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 2026-09-29T14:38:43.971123+00:00.
Case digest / 2f0f11b54fa46e4c004724d40e5d0d6ed15397befb828eb9c40986f63eed0ec2