Reproducing the Error

valet_reproduce_error.md

/** Create a Data object **/
let dataBlob = "foo".data(using: .utf8)

let existingEntryData: [String: Any] = [
    kSecAttrService as String!: Bundle.main.bundleIdentifier as Any,
    // Use Data object for kSecAttrAccount, which expects a String
    kSecAttrAccount as String!: dataBlob as Any, 
    kSecClass as String!: kSecClassGenericPassword as Any,
    kSecValueData as String!: dataBlob as Any
]

// Insert the non-conforming data into the keychain
let status = SecItemAdd(existingEntryData as CFDictionary, nil)
print(String(describing: status)) // prints “0” indicating a successful insert

let valet = VALValet(
    identifier: Bundle.main.bundleIdentifier!, accessibility: .whenUnlocked
)

let query: [String: Any] = [
    kSecAttrService as String!: Bundle.main.bundleIdentifier as Any,
    kSecClass as String!: kSecClassGenericPassword as Any
]

/**
  Attempt to migrate the existing non-conforming entry so Valet can manage it.
  
  #### THIS THROWS THE EXPECTED EXCEPTION!!! ####
  */
valet?.migrateObjects(matchingQuery: query, removeOnCompletion: true)