Hello,

there seems to be a problem with the listescape plugin and shared INBOX:

=== Preconditions:

• Dovecot 2.2.21 (or 2.2.13)
• IMAP
• Separator /
• Namespace-prefixes "INBOX/" and "shared/%%u/"
• Maildir(++)
• option mail_plugins = acl listescape
• option mail_shared_explicit_inbox = no
• User "owner" shares the INBOX
• ACLs set for another user "reader", so "reader" is able to access the shared INBOX of "owner"

=== Steps to reproduce by using IMAP commands at a telnet session:

• a1 login reader password
• a2 select shared/owner

=== Result: Selecting the shared INBOX fails with a response like: a2 NO Mailbox doesn't exist: shared/owner

=== Expected: The "select" command works.

=== Analysis: The function "mailbox_list_default_get_storage_name" (lib-storage/mailbox-list.c) does not work as expected when using the mail_plugin "listescape". It compares the mailbox name to the namespace prefix. Since the mailbox name is escaped a few lines before, the comparison yields "strings differ", which makes accessing the shared INBOX fail.

For example: for a string vname (mailbox name) "shared/owner", it compares "shared.owner" (escaped string) to the list->ns->prefix which is "shared/owner".

Asuming that the stored prefix should not be escaped, there should be a comparison of the unescaped name to the unescaped prefix (or the escaped name to the escaped prefix?).

=== Patch: Attached is a small patch which shows a possible solution. When applied, the problem is solved, i.e. the shared INBOX is accessible then. Important note: this patch is experimental, it works for the described special case but might not work with a different configuration or might even break things.

Best Regards, Rudolf Körner