731946 - Thunderbird loses track of INBOX subfolders when using | as folder separator

Status: UNCONFIRMED

(MailNews Core :: Networking: IMAP, defect)

Description

[Antonis Kanouras]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:10.0.2) Gecko/20100101 Firefox/10.0.2
Build ID: 20120216115113

Steps to reproduce:

I added a new IMAP account, let Thunderbird download all messages in all folders, and restarted it afterwards.


Actual results:

After the restart, there were folders named "INBOX|subfolder1", "INBOX|subfolder1" instead of "subfolder1", "subfolder2" under the Inbox. After clicking on one of them, they disappeared and got replaced by "subfolder1", "subfolder2" as they should be normally. However, Thunderbird had to redownload the messages (even their headers) for these folders. This also has the side-effect of those folders not being available offline.

This bug did *not* occur for folders outside the Inbox.


Expected results:

There should have been folders like "subfolder1", "subfolder2" under the inbox and Thunderbird shouldn't have to redownload all messages in them.

The IMAP server used is Dovecot 1.2.15-7 as packaged in Debian Squeeze and is configured as follows:
1 namespace, "", with "|" as the folder separator (perfectly legal, set up this way so that users can use "." and "/" in folder names)
Folders can be created outside of INBOX.

Also, this bug is occuring on either Windows or Linux, with versions of Thunderbird at least as old as 7 and as new as 10.0.2.

As minor as it would seem, when there are subfolders with many messages in them, Thunderbird ends up redownloading hundreds of megabytes of data on each restart, all the while being unable to display many messages in those folders. Now, multiply that by the number of computers in an office...