{"abstract":"An older refresh completion overwrites a newer cached representation.","category":"Caching","checks":4,"contract":"Entries are [globally comparable integer version,value]. Install incoming only when its version is strictly greater; equal or older completions preserve current state.","evaluation_group":"xc-refresh-version-order","failed_approach":"Requiring a gap larger than one rejects the immediate next valid revision.","family":"xc-refresh-version-order","id":"FA-10506","implementations":{"attempt":{"sha256":"74e6093311b261227dd0b4c1bfb533da608126a49413c8d632bed129f78b41e8","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(entry, incoming):\n    return list(incoming) if incoming[0]>entry[0]+1 else list(entry)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*([3, 'new'], [2, 'old'])), [3, 'new'])\ncheck('fixture 2', solve(*([3, 'old'], [4, 'new'])), [4, 'new'])\ncheck('fixture 3', solve(*([3, 'kept'], [3, 'duplicate'])), [3, 'kept'])\ncheck('fixture 4', solve(*([0, None], [5, 'value'])), [5, 'value'])\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":"110c15001ea4d4777198e9f7d893573cee44600c407d269a53bb56081717badc","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(entry, incoming):\n    return list(incoming)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*([3, 'new'], [2, 'old'])), [3, 'new'])\ncheck('fixture 2', solve(*([3, 'old'], [4, 'new'])), [4, 'new'])\ncheck('fixture 3', solve(*([3, 'kept'], [3, 'duplicate'])), [3, 'kept'])\ncheck('fixture 4', solve(*([0, None], [5, 'value'])), [5, 'value'])\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"},"fixed":{"sha256":"2d245f60bf8a7feeda636a8a555debbe90e4cc07bc96d93b9b857b2a41a05c78","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(entry, incoming):\n    return list(incoming) if incoming[0]>entry[0] else list(entry)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*([3, 'new'], [2, 'old'])), [3, 'new'])\ncheck('fixture 2', solve(*([3, 'old'], [4, 'new'])), [4, 'new'])\ncheck('fixture 3', solve(*([3, 'kept'], [3, 'duplicate'])), [3, 'kept'])\ncheck('fixture 4', solve(*([0, None], [5, 'value'])), [5, 'value'])\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-refresh-version-order","generated_at":"2026-09-29T14:38:39.664204+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.","repair":"Preserve the cache-state invariant: Entries are [globally comparable integer version,value]. Install incoming only when its version is strictly greater; equal or older completions preserve current state.","root_cause":"Completion arrival order replaces authoritative version ordering.","sha256":"faed05f7635531b8c3cd7f897800a2386ba9f8b619c60191900ead0e0320cb39","title":"An older refresh completion overwrites a newer cached representation · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":37.352,"exit_code":1,"observations":[{"actual":[3,"new"],"check":"fixture 1","expected":[3,"new"],"passed":true},{"actual":[3,"old"],"check":"fixture 2","expected":[4,"new"],"passed":false},{"actual":[3,"kept"],"check":"fixture 3","expected":[3,"kept"],"passed":true},{"actual":[5,"value"],"check":"fixture 4","expected":[5,"value"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [3, \"new\"], \"expected\": [3, \"new\"], \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": [3, \"old\"], \"expected\": [4, \"new\"], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [3, \"kept\"], \"expected\": [3, \"kept\"], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [5, \"value\"], \"expected\": [5, \"value\"], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":37.332,"exit_code":1,"observations":[{"actual":[2,"old"],"check":"fixture 1","expected":[3,"new"],"passed":false},{"actual":[4,"new"],"check":"fixture 2","expected":[4,"new"],"passed":true},{"actual":[3,"duplicate"],"check":"fixture 3","expected":[3,"kept"],"passed":false},{"actual":[5,"value"],"check":"fixture 4","expected":[5,"value"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [2, \"old\"], \"expected\": [3, \"new\"], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [4, \"new\"], \"expected\": [4, \"new\"], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [3, \"duplicate\"], \"expected\": [3, \"kept\"], \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": [5, \"value\"], \"expected\": [5, \"value\"], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":38.417,"exit_code":0,"observations":[{"actual":[3,"new"],"check":"fixture 1","expected":[3,"new"],"passed":true},{"actual":[4,"new"],"check":"fixture 2","expected":[4,"new"],"passed":true},{"actual":[3,"kept"],"check":"fixture 3","expected":[3,"kept"],"passed":true},{"actual":[5,"value"],"check":"fixture 4","expected":[5,"value"],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [3, \"new\"], \"expected\": [3, \"new\"], \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": [4, \"new\"], \"expected\": [4, \"new\"], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [3, \"kept\"], \"expected\": [3, \"kept\"], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [5, \"value\"], \"expected\": [5, \"value\"], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}