{"abstract":"Play-next items are inserted before the playing item.","category":"Media playlist state","checks":4,"contract":"Insert a batch immediately after the current valid entry, retaining batch order and the playing entry.","contract_signature":"entries, current, added","evaluation_group":"xmed-play-next-insertion-order","failed_approach":"Repeated stack-style insertion reverses the requested batch order.","family":"xmed-play-next-insertion-order","id":"FA-11056","implementations":{"attempt":{"sha256":"50b3e22b0369846b7e6f2356beaeb7f08ae73fabfe807a0cf3ec00ef5c2bcd46","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(entries, current, added):\n    return entries[:current+1]+list(reversed(added))+entries[current+1:]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*(['a', 'b'], 0, ['x', 'y'])),['a', 'x', 'y', 'b'])\ncheck('fixture 2',solve(*(['a'], 0, ['x'])),['a', 'x'])\ncheck('fixture 3',solve(*(['a', 'b'], 1, [])),['a', 'b'])\ncheck('fixture 4',solve(*(['a', 'b', 'c'], 1, ['x', 'y'])),['a', 'b', 'x', 'y', 'c'])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"c70c6b2d36700dfe1cf8443d1ba9f6b9ef64ef5cff0f58ef012bf97d4e5cdf81","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(entries, current, added):\n    return entries[:current]+list(added)+entries[current:]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*(['a', 'b'], 0, ['x', 'y'])),['a', 'x', 'y', 'b'])\ncheck('fixture 2',solve(*(['a'], 0, ['x'])),['a', 'x'])\ncheck('fixture 3',solve(*(['a', 'b'], 1, [])),['a', 'b'])\ncheck('fixture 4',solve(*(['a', 'b', 'c'], 1, ['x', 'y'])),['a', 'b', 'x', 'y', 'c'])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":" 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.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"xmed-play-next-insertion-order","generated_at":"2026-09-29T14:38:44.589761+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic local media controller stage; metadata and downloaded data are supplied explicitly. No external player, service or codec is required.","root_cause":"Play-next items are inserted before the playing item.","sha256":"2029f5f26d718fb4f8a52588228577b347432ee0e743fe090adafd722cdb37b1","title":"Play next insertion order · case 01","variant":1,"variant_policy":"The five numbered cases rerun the same authored boundary fixtures; they are reproducibility runs, not independent input variants.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":39.246,"exit_code":1,"observations":[{"actual":["a","y","x","b"],"check":"fixture 1","expected":["a","x","y","b"],"passed":false},{"actual":["a","x"],"check":"fixture 2","expected":["a","x"],"passed":true},{"actual":["a","b"],"check":"fixture 3","expected":["a","b"],"passed":true},{"actual":["a","b","y","x","c"],"check":"fixture 4","expected":["a","b","x","y","c"],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [\"a\", \"y\", \"x\", \"b\"], \"expected\": [\"a\", \"x\", \"y\", \"b\"], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [\"a\", \"x\"], \"expected\": [\"a\", \"x\"], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [\"a\", \"b\"], \"expected\": [\"a\", \"b\"], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [\"a\", \"b\", \"y\", \"x\", \"c\"], \"expected\": [\"a\", \"b\", \"x\", \"y\", \"c\"], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":41.245,"exit_code":1,"observations":[{"actual":["x","y","a","b"],"check":"fixture 1","expected":["a","x","y","b"],"passed":false},{"actual":["x","a"],"check":"fixture 2","expected":["a","x"],"passed":false},{"actual":["a","b"],"check":"fixture 3","expected":["a","b"],"passed":true},{"actual":["a","x","y","b","c"],"check":"fixture 4","expected":["a","b","x","y","c"],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [\"x\", \"y\", \"a\", \"b\"], \"expected\": [\"a\", \"x\", \"y\", \"b\"], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [\"x\", \"a\"], \"expected\": [\"a\", \"x\"], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [\"a\", \"b\"], \"expected\": [\"a\", \"b\"], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [\"a\", \"x\", \"y\", \"b\", \"c\"], \"expected\": [\"a\", \"b\", \"x\", \"y\", \"c\"], \"passed\": false}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}