"Syntax error in untagged Fetch response. Unexpected token: '('" (Domino IMAP4 Server)

[zmarkusdev]

Describe the bug
Hi!

I am trying to fetch from a Domino IMAP4 Server with the following fetch command:
IList<IMessageSummary> results = folder.Fetch(0,-1, MessageSummaryItems.Envelope | MessageSummaryItems.BodyStructure | MessageSummaryItems.UniqueId);

I am getting the following error:

Syntax error in untagged FETCH response. Unexpected token: '('

In this special case I tried to fetch the messages in the folder "Trash", in other folders, the fetch command ran successfully.

To Reproduce
Steps to reproduce the behavior:

1. Connect with Lotus Domino Server via IMAP
2. Open folder "Trash"
3. Try to fetch messages with the options "MessageSummaryItems.Envelope | MessageSummaryItems.BodyStructure | MessageSummaryItems.UniqueId"
4. Exception is thrown

Expected behavior
I expected to get the list of messages in the trash folder returned.

Desktop (please complete the following information):

• OS: Windows 10
• .Net Framework 4.6.1
• Version 2.3.1.6

Additional context
Here is my imap.log for further details:

Connected to imap://qqq1.dpi.local:143/?starttls=when-available
S: * OK Domino IMAP4 Server Release 10.0.1FP3 ready Wed, 30 Oct 2019 09:28:06 +0100
C: A00000000 CAPABILITY
S: * CAPABILITY IMAP4rev1 AUTH=PLAIN LITERAL+ NAMESPACE QUOTA UIDPLUS
S: A00000000 OK CAPABILITY completed
C: A00000001 AUTHENTICATE PLAIN
S: +
C: *************************************
S: A00000001 OK AUTHENTICATE completed
C: A00000002 CAPABILITY
S: * CAPABILITY IMAP4rev1 AUTH=PLAIN LITERAL+ NAMESPACE QUOTA UIDPLUS
S: A00000002 OK CAPABILITY completed
C: A00000003 NAMESPACE
S: * NAMESPACE (("" "\")) (("Andere Benutzer\" "\")) (("&ANY-ffentliche Ordner\" "\"))
S: A00000003 OK NAMESPACE completed
C: A00000004 LIST "" "INBOX"
S: * LIST (\Noinferiors \HasNoChildren) "\" Inbox
S: A00000004 OK LIST completed
C: A00000005 LIST "" Trash
S: * LIST (\Noinferiors \HasNoChildren) "\" Trash
S: A00000005 OK LIST completed
C: A00000006 EXAMINE Trash
S: * 3166 EXISTS
S: * 0 RECENT
S: * OK [UIDVALIDITY 8] UIDs valid
S: * OK [UIDNEXT 200010] Predicted next UID
S: * FLAGS (\Flagged \Seen \Answered \Deleted \Draft)
S: * OK [PERMANENTFLAGS ()] No permanent flags permitted
S: A00000006 OK [READ-ONLY] EXAMINE completed
C: A00000007 FETCH 1:* (UID ENVELOPE BODYSTRUCTURE)
S: * 2 FETCH (UID 14935 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 4 FETCH (UID 14937 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 3 FETCH (UID 14936 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 1 FETCH (UID 14934 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 6 FETCH (UID 14939 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 5 FETCH (UID 14938 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 8 FETCH (UID 14941 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 7 FETCH (UID 14940 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 10 FETCH (UID 14943 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 9 FETCH (UID 14942 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 14 FETCH (UID 14947 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 13 FETCH (UID 14946 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 15 FETCH (UID 14948 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 11 FETCH (UID 14944 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 12 FETCH (UID 14945 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 17 FETCH (UID 14950 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 16 FETCH (UID 14949 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 19 FETCH (UID 14952 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 18 FETCH (UID 14951 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 20 FETCH (UID 14953 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 21 FETCH (UID 14954 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 24 FETCH (UID 14957 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 23 FETCH (UID 14956 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 22 FETCH (UID 14955 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 25 FETCH (UID 14958 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 26 FETCH (UID 14959 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 28 FETCH (UID 14961 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 27 FETCH (UID 14960 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 29 FETCH (UID 14962 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))
S: * 30 FETCH (UID 14963 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEX

[jstedfast]

The problem is that the IMAP server is adding an extra set of ()'s around the ENVELOPE segment of the response:

S: * 2 FETCH (UID 14935 (ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))

It should, instead, look like this:

S: * 2 FETCH (UID 14935 ENVELOPE (NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL) BODYSTRUCTURE ("TEXT" "PLAIN" NIL NIL NIL "7BIT" 0 0 NIL))

[jstedfast]

Do you have custom work-arounds for Domino bugs?

I ask because in my attempt to unit test this fix, I discovered more bugs in Domino Server in that it doesn't escape the \ character when inside of a quoted-string token which is breaking MailKit as well in commands like NAMESPACE and LIST.

[jstedfast]

You can test the above fix by installing the latest MailKit nuget from https://www.myget.org/feed/mimekit/package/nuget/MailKit

[jstedfast]

Never mind about the \ issue, it seems GitHub's editor is rendering a double-\ as a single \.

[zmarkusdev]

Thanks for the fix, works as expected!