Backup file from FossifyCalendar fails at re-import

[alchemiker]

Checklist

• I can reproduce the bug with the latest version given here.
• I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
• This issue contains only one bug.
• I have read and understood the contribution guidelines.

Affected app version

1.10.3

Affected Android/Custom ROM version

Android 11

Affected device model

Nokia 6.2

How did you install the app?

F-Droid / IzzyOnDroid

Which calendar service or provider do you use, if any?

NextCloud (not relevant to bug I think)

Which sync adapter app do you use for calendar synchronization, if any?

DAVx5

Steps to reproduce the bug

TL;DR: I was switching from Google PlayStore version to F-Droid version, but the import of the local events fails.

1. Have Google Play Store Fossify Calendar (Beta, updated regularly) on your phone with two NextCloud calendars and several local calendars. Not using any tasks.
2. Have regular backups as .ics files to a dedicated folder on your phone activated.
3. Do "Export events to an .ics file" just to make sure.
4. Do "Export settings".
5. Deinstall app.
6. Install app from F-Droid.
7. Import settings.
8. Connect synchronized calendars and observe them connect nicely and show all events.
9. Import backup as .ics file (163 KB) and
10. Observe the following toast notifications:
    1. "Importing..."
    2. "Error: android.database.sqlite.SQLiteException"
    3. "Importing some entries failed"
11. Observe that actually import of ALL entries failed.
12. Try different "standard calendars", try to ignore calendar type, try import other, previous backups - all fail with the same toasts.

Expected behavior

After step 9., I would expect to have my events imported to my calendar, i.e. showing up in the monthly view on my phone in the app.

Actual behavior

I don't see them added. I see that the event classes (e.g. "Birthdays") appear in the lowest bar, but no actual events.

Screenshots/Screen recordings

No response

Additional information

I don't feel comfortable sharing the whole file with the entire internet since it contains some sensitive data, but if you are a known maintainer of this app and share an e-mail adress with me I can sent you the file. I suppose there is something not properly escaped from the event names or descriptions.