{"abstract":"An expiration sweep stops at a live entry and leaves later expired entries.","category":"Caching","checks":4,"contract":"Entries have arbitrary order and are [key,exclusive expiration timestamp]. Sweep every expired entry while preserving survivor order; do not assume expiration and recency share order.","contract_signature":"entries, now","evaluation_group":"xc-expired-sweep-mixed-order","failed_approach":"Scanning all entries while making expiration inclusive leaves entries at their deadline.","family":"xc-expired-sweep-mixed-order","id":"FA-10511","implementations":{"attempt":{"sha256":"032a03d76b6d5fffcd27b7eb25a13e5904d0cafdea6af152db1a726cb7a497d3","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(entries, now):\n    return [x for x in entries if x[1]>=now]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*([['a', 20], ['b', 5], ['c', 30]], 10)), [['a', 20], ['c', 30]])\ncheck('fixture 2', solve(*([['a', 10], ['b', 11]], 10)), [['b', 11]])\ncheck('fixture 3', solve(*([], 10)), [])\ncheck('fixture 4', solve(*([['a', 1], ['b', 2]], 10)), [])\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":"1bbe6fefaf963aaf46bd52d60aaa6e58a1b8bdf4da6b42cfd0547430f9f9516b","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(entries, now):\n    out=list(entries)\n    while out and out[0][1]<=now:\n        out.pop(0)\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*([['a', 20], ['b', 5], ['c', 30]], 10)), [['a', 20], ['c', 30]])\ncheck('fixture 2', solve(*([['a', 10], ['b', 11]], 10)), [['b', 11]])\ncheck('fixture 3', solve(*([], 10)), [])\ncheck('fixture 4', solve(*([['a', 1], ['b', 2]], 10)), [])\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":"xc-expired-sweep-mixed-order","generated_at":"2026-09-29T14:38:39.701756+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic cache state transformation. Inputs are copied or treated as immutable; no remote storage, real clock, or concurrent interleaving is simulated.","root_cause":"An access-ordered cache is incorrectly treated as expiration-ordered.","sha256":"b1dc701fbcccd9f118d6f6accc5c8877c91ed7513dcf02106a773313fc199896","title":"An expiration sweep stops at a live entry and leaves later expired entries · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":39.544,"exit_code":1,"observations":[{"actual":[["a",20],["c",30]],"check":"fixture 1","expected":[["a",20],["c",30]],"passed":true},{"actual":[["a",10],["b",11]],"check":"fixture 2","expected":[["b",11]],"passed":false},{"actual":[],"check":"fixture 3","expected":[],"passed":true},{"actual":[],"check":"fixture 4","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [[\"a\", 20], [\"c\", 30]], \"expected\": [[\"a\", 20], [\"c\", 30]], \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": [[\"a\", 10], [\"b\", 11]], \"expected\": [[\"b\", 11]], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.069,"exit_code":1,"observations":[{"actual":[["a",20],["b",5],["c",30]],"check":"fixture 1","expected":[["a",20],["c",30]],"passed":false},{"actual":[["b",11]],"check":"fixture 2","expected":[["b",11]],"passed":true},{"actual":[],"check":"fixture 3","expected":[],"passed":true},{"actual":[],"check":"fixture 4","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [[\"a\", 20], [\"b\", 5], [\"c\", 30]], \"expected\": [[\"a\", 20], [\"c\", 30]], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [[\"b\", 11]], \"expected\": [[\"b\", 11]], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [], \"expected\": [], \"passed\": true}], \"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."}}