FA-11061 / Media playlist state / Open access
Clear upcoming keeps history · case 01
An exclusive slice ending at current also removes the playing entry.
ROOT CAUSE
An exclusive slice ending at current also removes the playing entry.
VERIFIED REPAIR
Preserve the media contract: Clear only entries after a valid current index; retain playback history and the current entry.
Unsuccessful approach: Retaining only current destroys already-played history.
Case contract
Clear only entries after a valid current index; retain playback history and the current entry.
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(entries, current):
return entries[:current]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*(['a', 'b', 'c'], 1)),['a', 'b'])
check('fixture 2',solve(*(['a', 'b'], 0)),['a'])
check('fixture 3',solve(*(['a'], 0)),['a'])
check('fixture 4',solve(*(['a', 'b'], 1)),['a', 'b'])
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 | ['a'] | ['a', 'b'] | Failed |
| fixture 2 | [] | ['a'] | Failed |
| fixture 3 | [] | ['a'] | Failed |
| fixture 4 | ['a'] | ['a', 'b'] | Failed |
SHA-256 / 2f9007a7ff45fcd0e64ea5245dc984ddad5ef2e8428b1d18e0289d8087e16f3a
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(entries, current):
return [entries[current]]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*(['a', 'b', 'c'], 1)),['a', 'b'])
check('fixture 2',solve(*(['a', 'b'], 0)),['a'])
check('fixture 3',solve(*(['a'], 0)),['a'])
check('fixture 4',solve(*(['a', 'b'], 1)),['a', 'b'])
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'] | ['a', 'b'] | Failed |
| fixture 2 | ['a'] | ['a'] | Passed |
| fixture 3 | ['a'] | ['a'] | Passed |
| fixture 4 | ['b'] | ['a', 'b'] | Failed |
SHA-256 / c68c4bc2629205da64ec65a4919523df0ab64f677523915eaba17d37aaf6e57f
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(entries, current):
return entries[:current+1]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*(['a', 'b', 'c'], 1)),['a', 'b'])
check('fixture 2',solve(*(['a', 'b'], 0)),['a'])
check('fixture 3',solve(*(['a'], 0)),['a'])
check('fixture 4',solve(*(['a', 'b'], 1)),['a', 'b'])
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 | ['a', 'b'] | ['a', 'b'] | Passed |
| fixture 2 | ['a'] | ['a'] | Passed |
| fixture 3 | ['a'] | ['a'] | Passed |
| fixture 4 | ['a', 'b'] | ['a', 'b'] | Passed |
SHA-256 / caf2832abd57912891494dcf4f6f8b5f7528723ed00fdf0fe78802c97d848733
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 2026-09-29T14:38:44.624481+00:00.
Case digest / fc27ac5d6e850ac9e2e529f610c9083fd4365852bd187e5f2eb5c6d25d70117d