Tasks disappear in OpenTasks app and DAVdroid is synchronizing for minutes

[akn]

Hello,

I'm using DAVdroid 1.6.5-play on my Samsung Galaxy A3 (2017) with Android 6.0.1 to synchronize Calendar, Contacts and Tasks with nextcloud 12.0.1.

Every time I close the OpenTask app manually, all tasks are gone. Then DAVdroid starts to synchronize for minutes while the tasks slowly appear again one after the other.

I already reinstalled the OpenTasks app and DAVdroid.

[rfc2822]

Please provide steps to reproduce (including logs from the server), debug info, verbose logs etc..

[akn]

Here is the debug info (repeating entries shortened - original file over 100 MB size): 0_1502727707032_davdroid-12077-20170814-172503.txt

1. I started debugging.
2. I closed the OpenTasks app manually.
3. I opened the OpenTasks app again - all tasks gone.
4. DAVdroid starts to synchronize.
5. I stopped debugging.

[rfc2822]

1. I don't see any problem with DAVdroid. What makes you think that this is a DAVdroid problem? I had a similar problem after a major Android upgrade, and I'm quite sure that it was a system bug because it went away when I uninstalled both OpenTasks and DAVdroid and then installed them again. Did you already try that?
2. Seems like you have many tasks:

2017-08-14 17:26:25 15 [syncadapter.TasksSyncManager] Downloading 1175 tasks (30 at once)

so that 1175 tasks have to be synchronized every time. If you want this to scale, I suggest to archive finished tasks somewhere else.

[akn]

It looked like a DAVdroid problem in the beginning. Later in the day I noticed, that closing the OpenTasks app causes the problem somehow.

Addition: Not just every time I close the OpenTask app manually and open it again, all tasks are gone. This also happes by itself after some minutes. Then DAVdroid starts to synchronize them again.

I already reinstalled both apps. Serveral times.

I'll delete or archive the finished tasks.

Thank you so far.

[rfc2822]

If there's any specific indication that this could be a DAVdroid problem, please post it here.

[akn]

Another phenomenon today: All tasks twice in OpenTasks app. They all disappear again when I close it. Then synchronization as usual...

[akn]

Problem solved. It was the OpenTasks app.

SOLUTION: In the permissions settings of the OpenTasks app the option "Contacts" (in german "Kontakte") has to be turned on.

https://github.com/dmfs/opentasks/issues/404

Thanks for your help.