MailKit - invalid character in folder name

Question

MailKit is throwing the following exception when there is a folder containing ] or [ in its name:

MailKit.Net.Imap.ImapProtocolException: Syntax error in untagged STATUS response. Unexpected token: ']'
   at MailKit.Net.Imap.ImapEngine.UpdateStatus(CancellationToken cancellationToken)
   at MailKit.Net.Imap.ImapEngine.ProcessUntaggedResponse(CancellationToken cancellationToken)
   at MailKit.Net.Imap.ImapCommand.Step()
   at MailKit.Net.Imap.ImapEngine.Iterate()
   at MailKit.Net.Imap.ImapEngine.Wait(ImapCommand ic)
   at MailKit.Net.Imap.ImapFolder.GetSubfolders(StatusItems items, Boolean subscribedOnly, CancellationToken cancellationToken)

But the folder in question seems valid. Here is what I'm getting back from the server:

C: A00000006 LIST "" "INBOX.Trash.5454.%" RETURN (SUBSCRIBED CHILDREN STATUS (UIDVALIDITY))
S: * LIST (\HasNoChildren \UnMarked) "." INBOX.Trash.5454.2121]
S: * STATUS INBOX.Trash.5454.2121] (UIDVALIDITY 1500382965)
S: A00000006 OK List completed (0.001 + 0.000 secs).

Has anyone else encountered such a problem, it seems this is due to a limitation in MailKit?

Answer 1

The ']' character is supposed to be quoted but whatever IMAP server you are connecting to is obviously not properly quoting it.

If you aren't already using MailKit 1.18.1, please try upgrading to see if that fixes the problem. 1.18.1 added a work-around for a similar issue but I'm not sure if it handles it in an untagged STATUS response. If it doesn't, let me know, and I'll add the same work-around there.