Trying to create User of External UserType against a SqlManagedInstance results in error

先从 UserBase.cs 中围绕 UserType 验证的已引用代码行开始，然后检查 SqlSmoObject.cs 和 LocalizableResources.strings 中的引擎名称逻辑。在 SQL Managed Instance 上复现 External 用户创建，并验证验证逻辑接受该版本，且生成的错误能正确识别 Azure SQL Managed Instance。

Hi @shueybubbles, greetings from the dbatools team 😄

I'm trying to add a SqlUser of type [Microsoft.SqlServer.Management.Smo.UserType]::External on a newly created SQL MI.

DatabaseEngineEdition: SqlManagedInstance
ServerVersion.Major: 16
SMO Version: 16
File version: 16.200.46367.54

I'm getting the following exception:

Exception             : System.Management.Automation.MethodInvocationException: Exception calling "Create" with "0" argument(s): "Create failed for 
                        User 'claudio@********.onmicrosoft.com'. "
                         ---> Microsoft.SqlServer.Management.Smo.FailedOperationException: Create failed for User
                        'claudio@********.onmicrosoft.com'.
                         ---> Microsoft.SqlServer.Management.Smo.UnsupportedVersionException: 'User'.'UserType': 'External' is not a valid option for SQL Server 2017.

Code to reproduce:

$smoUser = New-Object Microsoft.SqlServer.Management.Smo.User
$smoUser.Parent = $dbSMO
$smoUser.Name = "claudio@********.onmicrosoft.com"
$smoUser.Login = "claudio@********.onmicrosoft.com"
$smoUser.UserType = [Microsoft.SqlServer.Management.Smo.UserType]::External
$smoUser.DefaultSchema = "dbo"
$smoUser.Create()

Note: with T-SQL it works.

From my analysis the problem is here (assuming the comment): https://github.com/microsoft/sqlmanagementobjects/blob/98093604e9ede97aa2a9b066279f0bd9d9557c4f/src/Microsoft/SqlServer/Management/Smo/UserBase.cs#L362-L364

It should be 12 <= this.ServerVersion.Major instead of >

Error message

Also, the error message says SQL Server 2017 when it should say SQL Server Managed Instance
It seems it's entering here:
https://github.com/microsoft/sqlmanagementobjects/blob/04249a2dc85ad1aa0d492b8a2cecf65583ded177/src/Microsoft/SqlServer/Management/Smo/SqlSmoObject.cs#L6919

I would suggest adding a new validation similar with
https://github.com/microsoft/sqlmanagementobjects/blob/04249a2dc85ad1aa0d492b8a2cecf65583ded177/src/Microsoft/SqlServer/Management/Smo/SqlSmoObject.cs#L6898-L6901

But like:

if (sp.TargetDatabaseEngineType == DatabaseEngineType.SqlAzureDatabase)
{
    return LocalizableResources.EngineCloud;
}
else if (sp.TargetDatabaseEngineType == DatabaseEngineType.Standalone && sp.DatabaseEngineEdition == DatabaseEngineEdition.SqlManagedInstance)
{
    return LocalizableResources.EngineCloudMI;
}

And add here:
https://github.com/microsoft/sqlmanagementobjects/blob/73cd2cb929409cb9ddc2c7b416c5d7c6ef621d5f/src/Microsoft/SqlServer/Management/Smo/LocalizableResources.strings#L26
A new entry

EngineCloudMI = Microsoft Azure SQL Managed Instance

PS: I'm more than happy to submit a PR with these changes if it's ok for you.
Thanks!