#62 Posteo, IMAP error, name contains server's hierarchy delimiter

[neo2001]

I'm using mbsync 1.3.5 (from Arch repo) and got the following error, for every subfolder inside another subfolder (at least that's what all GUI IMAP clients, like Thunderbird, show):
IMAP error: mailbox name Shopping.AliExpress contains server's hierarchy delimiter

I found this message odd, since the dot is actually the delimiter, so I wondered why it doesn't gets interpreted like that. But then again... what do I know....

After that, I tried the same configuration on another machine running Ubuntu and isync 1.3.0 (since that is whats in the Ubuntu repos) -- to my surprise it worked fine without error messages. The folder structure gets created as expected.

There may be other significant differences between these, but I just wanted to ask, if there were maybe changes between these versions that could lead to such a behavior?

Or is the behavior that seems correct to me actually not the expected behavior?

I'm not sure, but I think Posteo uses the Dovecot IMAP server -- if that's any help...

This is the configuration I'm using for both:

IMAPStore PosteoIMAP
Host posteo.de
Port 993
User xxxxxx.xxxxxx@posteo.de
PassCmd "pass posteo"
AuthMechs LOGIN
SSLType IMAPS
CertificateFile /etc/ssl/certs/ca-certificates.crt

MaildirStore PosteoMaildir 
Path ~/.Mail/Posteo/ 
Inbox ~/.Mail/Posteo/INBOX 
Subfolders Verbatim

Channel Posteo
Master :PosteoIMAP:
Slave :PosteoMaildir:
Create Both
Expunge Both
Patterns *
SyncState *
ExpireUnread no
MaxMessages 0

[Oswald Buddenhagen]

please run mbsync -a -l -D and post the log.

[neo2001]

Thank you for your fast reply!

I would paste the full logs, but I want to x out or cut down the personal stuff first. Maybe the following is enough (if not, please say so!)

Reading configuration file /home/xxx/.mbsyncrc
Channel Posteo
Opening master store PosteoIMAP...
M: [ 1] Enter connect_store
Resolving posteo.de... ok
Connecting to posteo.de (185.67.36.xxx:993)... 
M: [ 1] Leave connect_store
Opening slave store PosteoMaildir...
S: [ 2] Enter connect_store
S: [ 2] Callback enter connect_store, sts=0
pattern '*' (effective '*'): Path, no INBOX
S: [ 3] Enter list_store, flags=2
S: [ 3] Callback enter list_store

All folder are listed here on the working system (v1.3.0),
but only INBOX is shown on the non working system (v1.3.3)!
This is literally the only difference in the whole log file (checked with diff).

Listing looks like this (on the working system):

   Foo
   Bar/Dummy
   Bar

then

S: [ 3] Callback enter list_store
S: [ 3] Leave list_store
S: [ 2] Callback leave connect_store
S: [ 2] Leave connect_store
Connection is now encrypted
M: * OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE AUTH=PLAIN AUTH=LOGIN] Dovecot ready.
Logging in...
M: >>> 1 LOGIN <user> <pass>
M: 1 OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT MULTIAPPEND URL-PARTIAL CATENATE UNSELECT CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS SPECIAL-USE BINARY MOVE SEARCH=FUZZY COMPRESS=DEFLATE QUOTA] Logged in
M: >>> 2 COMPRESS DEFLATE
M: 2 OK Begin compression.
M: >>> 3 NAMESPACE
M: * NAMESPACE (("" ".")) NIL NIL
M: 3 OK Namespace completed.
M: [ 1] Callback enter connect_store, sts=0
pattern '*' (effective '*'): Path, no INBOX
M: [ 4] Enter list_store, flags=2
M: >>> 4 LIST "" "*"
M: [ 4] Leave list_store
M: [ 1] Callback leave connect_store

On both system the folders get listed correctly, like this:

M: * LIST (\HasNoChildren) "." Foo
M: * LIST (\HasChildren) "." Bar
M: * LIST (\HasNoChildren) "." Bar.SubDummy

then

M: 4 OK List completed.
M: [ 4] Callback enter list_store

then they get listed again (like the first time, but now on both systems), but with some spaces at the start of the line

   Foo
   Bar/Dummy
   Bar

and again without the spaces/tab at the start of the line and parent folders first instead last

Foo
Bar
Bar/Dummy

then

M: [ 5] Enter cancel_cmds
M: [ 5] Callback enter cancel_cmds
M: Enter free_store
M: Leave free_store
M: [ 5] Callback leave cancel_cmds
M: [ 5] Leave cancel_cmds
S: [ 6] Enter cancel_cmds
S: [ 6] Callback enter cancel_cmds
S: Enter free_store
S: Leave free_store
S: [ 6] Callback leave cancel_cmds
S: [ 6] Leave cancel_cmds
M: >>> 5 LOGOUT
M: [ 4] Callback leave list_store
M: * BYE Logging out
M: 5 OK Logout completed.

[neo2001]

In the initial report, I wrote version 1.3.5, because of the Arch package version, but the program itself is actually 1.3.3.

[Oswald Buddenhagen]

well, you obfuscated so much that i'm now not sure about the mapping to the original error message. would that be Bar.Dummy?
also, the log doesn't contain the error, which makes things more complicated. let's retry without -l, but instead of -a use a Posteo:Bar/Dummy with a reasonably small non-confidential mailbox (or send the log in private, that's fine as well). if that makes the error go away, try with -a after all.
but it's definitely "interesting" that you're getting a discrepancy on the maildir side.
commit c29eceaeeda seems like the only plausible candidate for such an error. please try with and without that it.

[neo2001]

I will test that on both systems and report back.

[neo2001]

Well, now it worked without any issues. Synced 2.1 GB and all folders without any errors at all.

I first tried a few dummy folders, I created and put some mails in them. That worked also fine. After that, I tried all....

The weird thing is, that the same config produced the error yesterday and besides cleaning up the mail folder, I did nothing else.

No idea how that happend... sorry! :-(

[Oswald Buddenhagen]

besides cleaning up the mail folder, I did nothing else.

that might be the key, though - what you reported looks like the remainders of an experiment with the Flatten option.

let's pick this up again in case you run into new evidence of a bug.

[neo2001]

Yes, I will report back if it shows up again.

Thank you, again!