Error when synchronising using 2.0.0 with maemo backends

[Merlijn Wajer]

Hi,

I'm struggling to set up synchronisation between my nextcloud 
webdav/caldav and my Maemo Leste (Devuan/Debian based) phone.

The strange thing is that it used to work with Syncevolution 1.5.3, on 
Devuan Beowulf, but it stopped working on Devuan Chimaera with version 
2.0.0.

I am following the steps described here (which used to work on 1.5.3):

https://leste.maemo.org/Sync#NextCloud_synchronizing

For the purpose of debugging, let's focus just on the calendar part, 
which means I would run this for the first sync:

> syncevolution --sync slow nextcloud nextcloudcal

but when I run the two-way sync I get a pretty strange error:

> [WARNING] nextcloud: ignoring username , it is not needed
> [INFO] @default/addressbook: inactive
> [INFO] @default/calendar: inactive
> [INFO] @default/contacts: inactive
> [INFO] @default/memo: inactive
> [INFO] @default/nextcloudjournal: inactive
> [INFO] @default/nextcloudtodo: inactive
> [INFO] @default/todo: inactive
> [WARNING] nextcloud: ignoring username , it is not needed
> Fatal: fieldlist '' not defined for fieldmap at line 3500 col 6
> Fatal error 20010, no valid configuration could be read from XML file
> [ERROR] internal error, invalid XML configuration (with datastores):

which I believe is this part of the XML (from the error log):

> [ERROR]       <!-- Mapping of the fields to the fieldlist -->
> [ERROR]       <fieldmap fieldlist=''>
> [ERROR]         <automap/>
> [ERROR]       </fieldmap>
> [ERROR] 

The error does not occur when I choose the "evolution-calendar" backend 
instead of "maemo-events".

So somehow the fieldlists are empty and this makes the whole setup 
unhappy. I can see that src/syncevo/SyncSource.cpp builds this list 
based on "info.m_fieldlist", but I can't really figure out why this list 
would be empty for the maemo-events backend.

Any clue what could be causing this issue?

Regards,
Merlijn