FAILURE MAP
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FA-10871 / Audio frame buffers / Open access

Read cursor advances consumed · case 01

Read cursor advances beyond end by requested rather than consumed count.

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

ROOT CAUSE

Read cursor advances beyond end by requested rather than consumed count.

THE FAILURE

Read cursor advances beyond end by requested rather than consumed count.

Unsuccessful approach: Not advancing cursor repeats samples on the next read.

Case contract

Read up to nonnegative requested mono samples from cursor in [0,length], returning data and next cursor limited by actual available samples.

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(samples, cursor, requested):
    return [samples[cursor:cursor+requested],cursor+requested]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*([1, 2, 3], 2, 5)),[[3], 3])
check('fixture 2',solve(*([1, 2, 3], 0, 2)),[[1, 2], 2])
check('fixture 3',solve(*([], 0, 3)),[[], 0])
check('fixture 4',solve(*([1], 0, 0)),[[], 0])
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 fixtureActualExpectedOutcome
fixture 1[[3], 7][[3], 3]Failed
fixture 2[[1, 2], 2][[1, 2], 2]Passed
fixture 3[[], 3][[], 0]Failed
fixture 4[[], 0][[], 0]Passed

SHA-256 / 49fc64100137e3dfebb712f8182a55f87f5e22db6c873db0909aac7285bb8a42

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(samples, cursor, requested):
    return [samples[cursor:cursor+requested],cursor]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*([1, 2, 3], 2, 5)),[[3], 3])
check('fixture 2',solve(*([1, 2, 3], 0, 2)),[[1, 2], 2])
check('fixture 3',solve(*([], 0, 3)),[[], 0])
check('fixture 4',solve(*([1], 0, 0)),[[], 0])
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 fixtureActualExpectedOutcome
fixture 1[[3], 2][[3], 3]Failed
fixture 2[[1, 2], 0][[1, 2], 2]Failed
fixture 3[[], 0][[], 0]Passed
fixture 4[[], 0][[], 0]Passed

SHA-256 / a1dd65ab42650dd7809080f11a72dee945cab50e17b24d03180b5715e11a1702

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 2026-09-29T14:38:42.985093+00:00.

Case digest / e5178dad2ae7d4ca31717a470d6024de5de9f6ad0ba357334119457335d2362c