Events are being duplicated

[jorohr]

DAVDroid has recently begun to duplicated repeating events [annot: just checked: This does not only affect repeating but also one time events, not all of them, though] from two of my calendars, both of which are from Nextcloud 11. One of the calendars being readonly, the other one read-write. I see one event 8 times for the same date, another one 4 and another one 2 times. I have no issues with them on other clients.

I used to observe the same problem in the past, but at some point it went away. Now it is back, for some reason.
If you need logs, I can happily provide both DAVdroid and nextcloud server logs, but I am not sure what kind of logs are needed, please advise.

My phone is running an unofficial version of CM 12.1, Android 5.1.1

[kuba-orlik]

I’m also experiencing this issue, and I’ve heard my friend is seeing this problem, as well…

So we see a lot of this:

We’re using Radicale on our back-end.

PS. Here’s the redacted debug.txt file: 0_1501152880784_debug.txt

[rfc2822]

Is there any way to reproduce this, for instance with a test account?

Does it only happen for recurring events? Some of these problems were fixed in newer calendar providers, so updating the Android version might help.

[kuba-orlik]

@rfc2822 said in Events are being duplicated:

Is there any way to reproduce this, for instance with a test account?

Not that I know of. The multiplication of events seems to happen at random

Does it only happen for recurring events?

I think that used to be the case some time ago, but now even single, non-repeating events appear multiple times in the calendar.

Some of these problems were fixed in newer calendar providers, so updating the Android version might help.

In fact I have not yet experienced the issue on a different device with newer Android version. Not sure about which Android version is my friend who is also experiencing this issue on, will get back to you on that one

[kuba-orlik]

I confirm that some event duplication also happens on Android 7

[benjamin.kwiatek]

Hi there,

I can confirm Kuba’s problem. And what makes it worse is that apparently it does not depend on the server.

I have the problem with both a NEXTCLOUD server and the Apple ICLOUD.

I have it with both single events and series.

Emptying calendar storage is just a temporary fix. The problem keeps coming back.

I have an Android 6 device (LG G4).

Sorry but I have to say: DAVdroid is not much use like this for me. You might want to remove at least iCloud and nextcloud from the compatibility list as it is misleading.

Liebe Grüße and sorry about being so harsh…
Tobias

PS: There was another bug description with the same symptoms. But that’s labelled SOLVED. Maybe you want to look into this problem more conscienciosly.

[rfc2822]

@benjamin-kwiatek In our tests and for thousands of Nextcloud and iCloud users, this problem does not occur so we won’t remove them from our list. We also use DAVdroid for ourselves and have not seen this problem.

Again: Is there a way to reproduce the problem? For instance, a test account for which the same steps lead to duplicated events? Without ever having seen this problem, I really can’t look into it.

[benjamin.kwiatek]

Hi rfc2822,

I know it’s a developer’s nightmare but Kuba stated correctly. IT HAPPENS RANDOMLY.

I’ve deleted my recent duplicates and recreated the event exactly as before.
But the duplication didn’t take place this time.

But the problem REALLY EXISTS and as Kuba confirms, it’s not just the fault of my sh**ty LG phone still waiting for Android 7…

Is there any way I can inspect the calendar storage since the problem seems to come from the way davdroid uses this layer? (Remember: I can make the problem go away be deleting all the calendar storage data and resyncing).

Tobias

[kuba-orlik]

I’ve recently switched to an old S2 with Android 7 (thanks, LineageOS!) and haven’t experienced the issue since. Not sure if it’s the case of OS or phone model now.

[rfc2822]

@benjamin-kwiatek said in Events are being duplicated:

Is there any way I can inspect the calendar storage since the problem seems to come from the way davdroid uses this layer? (Remember: I can make the problem go away be deleting all the calendar storage data and resyncing).

The best approach I know is to have DAVdroid logs on all the time and wait for some duplication, and then graze through all the logs.

You can also query the calendar storage by various methods. If you have a rooted phone, you can fetch the whole DB. Or you can do adb shell and then query the provider like content query --uri content://com.android.calendar/calendars (requires USB debugging active). You can view

• content query --uri content://com.android.calendar/calendars
• content query --uri content://com.android.calendar/events
• Instances

etc.

[transeuropa]

I have the same problem since a while running my own DaviCal server.

Until today I thought that the problem is related to the S-Planner app. But with the last update of DavDroid S-Planner crashes nearly on every operation, so I switched to DigiCal. But the duplicated entries remains.

The duplications in my case only appear on birthdays (which is 95% of my repeated events).
About 20% of the birthdays are not duplicated
About 50% of the birthdays are twice
About 30% of the birthdays are triple

Desktop applications (like Thunderbird Lightning or Apple Calendar) does not show this behaviour.

[transeuropa]

@transeuropa

Even more annoying is that my adressbook has since the same time also duplicated entries.

[rfc2822]

I have seen this problem when using Evolution and just reproduced an Evolution bug for recurring events.

Have you used other clients to edit the affected events? Which clients? Is this reproducible? Have you had a look at the .ics to see whether they are correct?

Please post the .ics of events for the duplicated events. We need much more info!

[benjamin.kwiatek]

Hi there,

recurring events may be additionally problematic. But as I’ve said: the problem is with plain single events.

However, I do use Android (Business calendar for that matter) and iCal on the Mac (nowadays just called Calendar) interchangeably to create and update my events.

But I have tried all the possible combinations (creation here, alteration there, etc and vice versa) for the event that had duplicated itself before. But I could not reproduce the problem.

I suspect the bug is a little more subtle…

Gruß Tobias

[kuba-orlik]

For some reason I am no longer affected by this issue, I didn’t change anything backend-wise. Hope the others experiencing this problem will find a fix!

[transeuropa]

@rfc2822

Here are 3 examples of not-duplicated, 3 examples of duplicated and 1 example of a triple entry.
Only the name in the Summary are made anonymous

6_1503756284512_triple1_anon.ics
5_1503756284512_notduplicated3_anon.ics
4_1503756284511_notduplicated2_anon.ics
3_1503756284511_notduplicated1_anon.ics
2_1503756284511_duplicated3_anon.ics
1_1503756284511_duplicated2_anon.ics
0_1503756284469_duplicated1_anon.ics

[transeuropa]

@kuba-orlik

Are you actively removed the duplicated entries and make them new or did the duplications disappeared automatically?

[kuba-orlik]

@transeuropa I dropped my old phone into a river. I’ve switched to a different device and I’m not experiencing the issue afterwards.

Not a strategy I’d recommend trying out, though.

[transeuropa]

@kuba-orlik

well, not an option for me
anyway - throwing the phone into a river does not alter the ics entries within the database - therefore I doubt that an invalid entry is the culprit. Probably it is related to caching of DavDroid?

Harald

[kuba-orlik]

I’ve just now noticed that one of my repeating events got duplicated. Seems like my river strategy didn’t pay off

So I confirm this issue exists on Android 7.

What’s interesting is that if I delete a single instance of the event, the other (duplicated) one disappears as well.