[Dovecot] TB, dovecot & trailing slash - again

Bruno Tréguier Bruno.Treguier at shom.fr
Thu Mar 3 23:28:39 EET 2011

Hi there,

I have been browsing the mailing list archives in search of a solution 
to my problem, related to the quite infamous "trailing slash" issue with 
Thunderbird, but I don't seem to have found any closely related 
discussion. Please forgive me if this problem has already found a 
solution. Here I go;

We use a lot of TB clients (2.x and 3.x), and we are using Dovecot 1.2.4 
on our production server (mbox format). As told in many places, 
including this list, I added the option "tb-extra-mailbox-sep" in my 
dovecot.conf file.

The checkbox regarding the mix of mailbox/submailbox and 
mailbox/messages is unchecked in the advanced options of our TB standard 

I snooped the connection with "ngrep" when creating a folder meant for 
containing subfolders. Here is the trace:

>  6 create "ABCDE/"..
<  6 OK Create completed...
>  7 subscribe "ABCDE/"..
<  7 OK Subscribe completed...
>  8 list "" "ABCDE/"..
<  * LIST (\Noselect \HasChildren) "/" "ABCDE/"..8 OK List completed...

So far, so good. But when you have a look at the .subscriptions file, 
you can see that the ABCDE folder has no trailing slash: it has been 
stripped off, apparently due to an "enhancement" made in 2009:


It may be intended, but the drawback is that TB then gets a bit 
confused, as it has no way, during a "LIST" operation, to distinguish 
between a "folder/subfolder" scheme and a "folder/message" scheme: 
consequently, you get an error message from TB whenever you click on the 
containing folder, stating that "the mailbox isn't selectable". The 
problem is not just cosmetic, though, as the subfolders of such folders 
are not synchronized when selected for offline reading.

I made a test with another version of Dovecot, of the 1.1 branch, and it 
behaves a little bit differently: the trailing slash is kept in the 
.subscriptions file, and everything is ok. TB is able to make the 
distinction between both kinds of folders.

For the moment, I simply erased the "tb-extra-mailbox-sep" from my 
config file, and this is what happens:

 >  306 create "ABCDE/"..
<  306 OK Create completed...
 >  307 subscribe "ABCDE/"..
<  307 NO Invalid mailbox name: ABCDE/..
 >  308 list "" "ABCDE/"..
<  * LIST (\Noselect \HasChildren) "/" "ABCDE/"..308 OK List completed...

In that case, the "subscribe" command fails, so the folder does not 
appear by itself in the .subscriptions file, but as it is not used (only 
"terminal" mailboxes, containing messages, which are files in the 
filesystem), this is not a problem. The directory is created on the 
disk, and you can then create subfolders without any problem...

Sorry for this long message, I just wanted to explain precisely what 

A last word: switching to maildir would be quite a hassle, as we use 
quite a lot of procmail-based  tools. Rewriting everything using Sieve 
is not planned for the moment.

Does anyone out there have a solution for this ? What am I doing wrong ? 
Is the "tb-extra-mailbox-sep" really necessary when using TB ? As far as 
I can tell, it rather got us into trouble here, than solved anything...

Thanks for any info/pointer/else !

Best regards,


- Service Hydrographique et Oceanographique de la Marine - DO/MGS/INF
-  13, rue du Chatellier -  CS 92803  - 29228 Brest Cedex 2, FRANCE
-     Phone: +33 2 98 22 17 49  -  Email: Bruno.Treguier at shom.fr

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