Calendar Export : Skipping calendar containing invalid calendar data

[acazenave]

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Steps to reproduce

1. php occ user:export USERNAME /tmp/ -t calendar -vvv
   Defaulted container "app" out of: app, web
   Exporting user information in user.json…
   Exporting settings in settings.json…
   Exporting versions in versions.json…
   Exporting calendars into dav/calendars/…
   Skipping calendar "USERNAME" containing invalid calendar data
   Skipping calendar "Anniversaires des contacts" containing invalid calendar data
   Skip non-selected migrator: contacts
   Skip non-selected migrator: trashbin
   Skip non-selected migrator: forms
   Skip non-selected migrator: passwords
   Skip non-selected migrator: account
   Skip non-selected migrator: files
   Export saved in /tmp/USERNAME_2024-10-21_09-27-55.zip

Expected behavior

Calendar should be exported successfully.

Actual behavior

1. Failing to export calendar with error "containing invalid calendar data" : It doesn't explain which data is invalid and why.
2. Even with '-vvv' option, log is not more verbose.

The export of this same calendar in web (through the UI in calendar app) works well.

Server configuration

Web server: Nginx

Database: PostgreSQL

PHP version: 8.2.23

Nextcloud version: 28.0.10

List of activated apps

- user_migration: 5.0.0

[acazenave]

I also have this issue when calendar is empty (but that's not really disturbing).
But I also have it for some calendars that are not empty, and log is not verbose enough to make me understand why.

[Pytal]

Could you provide the .ics file of the calendar which exports successfully via web but not the command?

[ilpssun]

I have a similar issue. Out of my 5 calendars, 2 do not export with the error message Skipping calendar "Name" containing invalid calendar data. I cannot provide these calendars as ics files because they contain sensitive data. How can I help debug this? What is the recommended way to migrate my calendars to the new Nextcloud instance?

[come-nc]

I have a similar issue. Out of my 5 calendars, 2 do not export with the error message Skipping calendar "Name" containing invalid calendar data. I cannot provide these calendars as ics files because they contain sensitive data. How can I help debug this? What is the recommended way to migrate my calendars to the new Nextcloud instance?

https://github.com/nextcloud/server/blob/00e1264ade2f34dce2a15b11089ba2c2ccd1221e/apps/dav/lib/UserMigration/CalendarMigrator.php#L118
Sadly it looks like the problems are not logged anywhere.
Are you able to patch the server code?
The first step would be to log the $problems var with something like:

diff --git a/apps/dav/lib/UserMigration/CalendarMigrator.php b/apps/dav/lib/UserMigration/CalendarMigrator.php
index 73e9c375490..f9fa9be345f 100644
--- a/apps/dav/lib/UserMigration/CalendarMigrator.php
+++ b/apps/dav/lib/UserMigration/CalendarMigrator.php
@@ -118,6 +118,7 @@ class CalendarMigrator implements IMigrator, ISizeEstimationMigrator {
                $problems = $mergedCalendar->validate();
                if (!empty($problems)) {
                        $output->writeln('Skipping calendar "' . $properties['{DAV:}displayname'] . '" containing invalid calendar data');
+                       $output->writeln('Problems: ' . json_encode($problems));
                        throw new InvalidCalendarException();
                }

And then see if the problems you have are things that should be ignored, fixed or simply listed in the output or the logs.

[ilpssun]

Thanks for your suggestion. Meanwhile, I found a workaround for me:

• Use the command line occ user:export USERNAME /tmp/ -t calendar -vvv to check whether any calendars have problems with the export
• If so, do not use the user-migration app but exclude the calendars from the export. Instead, use the calendar app to export all relevant calendars to ics files and import them manually using the calendar app in the new instance

[saimonn]

I could reproduce the bug with one of my calendars, and added the suggested log of $problems
Problems: "[{"level":3,"message":"An iCalendar object must have at least 1 component.","node":["vcalendar",[["calscale",{},"text","GREGORIAN"],["version",{},"text","2.0"],["prodid",{},"text","-\/\/SabreDAV\/\/SabreDAV\/\/EN"],["x-wr-calname",{},"unknown","Cal.example.org"],["x-apple-calendar-color",{},"unknown","#CC73E1"]],[]]}]

./occ user:export -vvv -- user1 /var/www/html/data/user1/files/export
Exporting user information in user.json…
Exporting settings in settings.json…
Exporting versions in versions.json…
Exporting calendars into dav/calendars/…
Skipping calendar "Cal.example.org" containing invalid calendar data
Problems: "[{"level":3,"message":"An iCalendar object must have at least 1 component.","node":["vcalendar",[["calscale",{},"text","GREGORIAN"],["version",{},"text","2.0"],["prodid",{},"text","-\/\/SabreDAV\/\/SabreDAV\/\/EN"],["x-wr-calname",{},"unknown","Cal.example.org"],["x-apple-calendar-color",{},"unknown","#CC73E1"]],[]]}]
Exporting contacts into dav/address_books/…
Exporting trashbin into files_trashbin…
Exporting trashbin files…
Exporting account information in settings/account.json…
Exporting profile config in settings/config.json…
Exporting files…
No file versions to export…
Exporting file tags…
Exporting file systemtags…
Exporting file comments…
Export saved in /var/www/html/data/user1/files/export/user1_2026-01-06_14-35-10.zip

I can export this calendar via the web interfaces and it seems to contains one single entry:

BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:-//SabreDAV//SabreDAV//EN
X-WR-CALNAME:Cal.example.org
X-APPLE-CALENDAR-COLOR:#CC73E1
REFRESH-INTERVAL;VALUE=DURATION:PT4H
X-PUBLISHED-TTL:PT4H
END:VCALENDAR

edit:
the calendar of another user on the same instance also fails:

Skipping calendar "Contact birthdays" containing invalid calendar data
Problems: "[{"level":3,"message":"An iCalendar object must have at least 1 component.","node":["vcalendar",[["calscale",{},"text","GREGORIAN"],["version",{},"text","2.0"],["prodid",{},"text","-\/\/SabreDAV\/\/SabreDAV\/\/EN"],["x-wr-calname",{},"unknown","Contact birthdays"],["x-apple-calendar-color",{},"unknown","#E9D859"]],[]]}]

both problems seems linked to an entry comming from the same iphone (that's the only know apple device on this nextcloud instance)

Version

Nextcloud community docker image 32.0.0