Progress sync issues

Hi there!
Since a few days, I’ve got issues with progress sync.

If I read on a single device, no problem. But if I launch a second device (even without opening a book on it), my progress goes completely awry. The book I’m currently reading goes a few percent back, and some books I’ve finished reading goes bask to in the reading list with a random progress percentage.

Any cue on how to debug and solve this?


[edit : ] additional information I forgot to mention : I’m streaming from Komga (if it’s relevant)

Well after multiple uninstall/reinstall on each devices, it seems good now. I’ll let you know if it happens again

It didn’t worked for long, and the issue is already back. Here is my support info :

Version: 2.9.7   Build: 202112090942   Env: Production 
Support Identifier:
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Thanks for all the info. We’ll look into this as soon as possible.

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Sorry for taking so long on getting back to you about this issue.

We finally found the problem!

We have a retain cycle in the Vertical Scroll reader that causes it to stay in memory even after you stop reading. The problem is that, indirectly, the reader holds an outdated copy of the reading session. Additionally, whenever you put the app in the background, it saves the reading session and synchronizes it with the backend.
If you open the same comic using the vertical reader multiple times, the app accumulates multiple copies of the reader with multiple outdated snapshots of the reading session.

If you are lucky, the latest session is stored and synced last. But if you are unlucky, the same happens with one of the outdated sessions. Causing random rollbacks of the progress :sweat:

We’ll submit a fix today and hopefully will be available in the upcoming days.

For now, I’d recommend not using the Vertical Scroll Reader if you care about having accurate reading progress tracking.

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Thanks a lot @dani !

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