[Dovecot] invalid mailbox name

[Vincent Schut]

On 03/13/2012 10:00 AM, Timo Sirainen wrote:
> On 13.3.2012, at 10.46, Vincent Schut wrote:
>
>> Hi,
>>
>> while migrating all mail from our old to our new server (using offlineimap, imap ->  imap), I get the following error for one of my user's mailboxes:
>>
>> ERROR: Folder 'Organisations.RS Env&  IJRS'[local_hoekman] could not be created. Server responded: ('NO', ['Invalid mailbox name: Organisations.RS Env&  IJRS'])
>>
>> I suppose this is because of the ampersand in the mailbox name? Because other folder with spaces in it go just fine...
>>
>> Is this a fixed thing? Why was my user able to create the folder once? And why is dovecot 1.2.15 refusing to create the folder now?
>
> Old Dovecot versions didn't enforce mailbox names to be valid, new ones do. I guess user had a broken IMAP client that created a mailbox with invalid name and now Dovecot refuses to do it again.
>
> Mailbox names are in "modified UTF-7" format. "&" character needs to be translated as"&-".
>

Timo,

thanks for the quick follow-up.
However, I'm afraid I don't really yet grasp your explanation about the 
utf-7 translation ("&" character needs to be translated as"&-"). To end 
my confusion, could you elaborate a bit on which of these 
interpretations is correct:

- when I want to create a folder with a "&" using a imap client, I have 
to type "&-"?
or:
- the imap client (offlineimap in this case) should translate the "&" 
into "&-" on the fly (I can do that, you can give folder translation 
functions in offlineimap)
or:
- the foldername on disk should contain "&-" instead of just "&" to 
denote the ampersand?

or did you mean something else altogether ("don't use folders with & in 
their names, they're evil")?

Vincent.