autoexpunge creates special_use folder

[Timo Sirainen]

On 11 Dec 2015, at 16:00, Tom Sommer <mail at tomsommer.dk> wrote:
> 
> namespace inbox {
>  mailbox Spam {
>    special_use = \Spam
>    auto = create
>    autoexpunge = 30d
>  }
> }
> 
> This creates the "Spam" folder in the filesystem on login/logout, even though it shouldn't.
> If I remove autoexpunge, the folder is not created.

I think this is something that doesn't need to be fixed. The folder will eventually be created anyway. And adding a check to avoid its creation causes an extra stat() syscall for most mailbox formats (only LAYOUT=index avoids that). The extra stat() could even mean extra disk I/O in some cases. So I think it's better to just have it create the folder since that gives slightly better overall performance.