{"abstract":"Updating one cached representation removes sibling variants.","category":"Caching","checks":4,"contract":"Unique entries are [resource,variant,value]. Replace only the exact pair and append its updated representation, preserving every other entry in order.","contract_signature":"entries, resource, variant, value","evaluation_group":"xc-variant-replacement-isolated","failed_approach":"Filtering by variant alone deletes matching variants of different resources.","family":"xc-variant-replacement-isolated","id":"FA-10486","implementations":{"attempt":{"sha256":"77dfa4bfa5fd60889cf21ea76fc8058f48a90223a39c1936861c4c8188930e87","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(entries, resource, variant, value):\n    return [x for x in entries if x[1]!=variant]+[[resource,variant,value]]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*([['r', 'en', 1], ['r', 'fr', 2]], 'r', 'en', 3)), [['r', 'fr', 2], ['r', 'en', 3]])\ncheck('fixture 2', solve(*([['r', 'en', 1], ['s', 'en', 2]], 'r', 'en', 3)), [['s', 'en', 2], ['r', 'en', 3]])\ncheck('fixture 3', solve(*([], 'r', 'en', 0)), [['r', 'en', 0]])\ncheck('fixture 4', solve(*([['r', 'fr', 2]], 'r', 'en', 3)), [['r', 'fr', 2], ['r', 'en', 3]])\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":"d7c6e91aebb4834ea25b2c300f18ce51245d26d118d6f5c76b37264a6107743f","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(entries, resource, variant, value):\n    return [x for x in entries if x[0]!=resource]+[[resource,variant,value]]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*([['r', 'en', 1], ['r', 'fr', 2]], 'r', 'en', 3)), [['r', 'fr', 2], ['r', 'en', 3]])\ncheck('fixture 2', solve(*([['r', 'en', 1], ['s', 'en', 2]], 'r', 'en', 3)), [['s', 'en', 2], ['r', 'en', 3]])\ncheck('fixture 3', solve(*([], 'r', 'en', 0)), [['r', 'en', 0]])\ncheck('fixture 4', solve(*([['r', 'fr', 2]], 'r', 'en', 3)), [['r', 'fr', 2], ['r', 'en', 3]])\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-variant-replacement-isolated","generated_at":"2026-09-29T14:38:39.395540+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":"Representation replacement filters by resource without retaining its variant dimension.","sha256":"39a91bbe8e80b7af810e0c468e4ab7b201d3c7c1fa9eaa7e4041c22b3b6f0a23","title":"Updating one cached representation removes sibling variants · 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":37.971,"exit_code":1,"observations":[{"actual":[["r","fr",2],["r","en",3]],"check":"fixture 1","expected":[["r","fr",2],["r","en",3]],"passed":true},{"actual":[["r","en",3]],"check":"fixture 2","expected":[["s","en",2],["r","en",3]],"passed":false},{"actual":[["r","en",0]],"check":"fixture 3","expected":[["r","en",0]],"passed":true},{"actual":[["r","fr",2],["r","en",3]],"check":"fixture 4","expected":[["r","fr",2],["r","en",3]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [[\"r\", \"fr\", 2], [\"r\", \"en\", 3]], \"expected\": [[\"r\", \"fr\", 2], [\"r\", \"en\", 3]], \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": [[\"r\", \"en\", 3]], \"expected\": [[\"s\", \"en\", 2], [\"r\", \"en\", 3]], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [[\"r\", \"en\", 0]], \"expected\": [[\"r\", \"en\", 0]], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [[\"r\", \"fr\", 2], [\"r\", \"en\", 3]], \"expected\": [[\"r\", \"fr\", 2], [\"r\", \"en\", 3]], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":44.882,"exit_code":1,"observations":[{"actual":[["r","en",3]],"check":"fixture 1","expected":[["r","fr",2],["r","en",3]],"passed":false},{"actual":[["s","en",2],["r","en",3]],"check":"fixture 2","expected":[["s","en",2],["r","en",3]],"passed":true},{"actual":[["r","en",0]],"check":"fixture 3","expected":[["r","en",0]],"passed":true},{"actual":[["r","en",3]],"check":"fixture 4","expected":[["r","fr",2],["r","en",3]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [[\"r\", \"en\", 3]], \"expected\": [[\"r\", \"fr\", 2], [\"r\", \"en\", 3]], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [[\"s\", \"en\", 2], [\"r\", \"en\", 3]], \"expected\": [[\"s\", \"en\", 2], [\"r\", \"en\", 3]], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [[\"r\", \"en\", 0]], \"expected\": [[\"r\", \"en\", 0]], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [[\"r\", \"en\", 3]], \"expected\": [[\"r\", \"fr\", 2], [\"r\", \"en\", 3]], \"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."}}