Non-existing or incorrectly formatted Tutanota attendee causes errors upon sending event updates and deletion

[jowlo]

Bug in web app

Describe the bug
When importing a calendar with an event that has an attendee with non-existing @tutanota.com address on it, import works but there is an error when looking at the details/edit view of that event.

To Reproduce
Steps to reproduce the behavior:

1. Import calendar with event with an non-existant tutanota attendee, for example:

BEGIN:VCALENDAR
PRODID:-//Tutao GmbH//Tutanota 3.83.0//EN
VERSION:2.0
CALSCALE:GREGORIAN
METHOD:PUBLISH
BEGIN:VEVENT
DTSTART:20210423T080000Z
DTEND:20210423T083000Z
DTSTAMP:20210423T105406Z
UID:asdfasdfasdf@tutanota.com
SEQUENCE:2
SUMMARY:testevent
ORGANIZER;EMAIL=test@tutanota.com:mailto:test@tutanota.com
ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=ACCEPTED;RSVP=TRUE;EMAIL=test@tutanota.com:mailto:test@tutanota.com
ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP=TRUE;CN="A girl is noone";EMAIL=someonewhodoesnotexist@tutanota.de:mailto:someonewhodoesnotexist@tutanota.de:
END:VEVENT
END:VCALENDAR

2. Import into calendar
3. Open edit view of the new event
4. See error

Expected behavior
No error shown

Screenshots
If applicable, add screenshots to help explain your problem.

Additional context
See #2974 for the same error when creating a new event

[vaf-hub]

The issue with the event you provided as an example is the trailing colon, not the fact that the Tutanota address does not exist:
ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP=TRUE;CN="A girl is noone";EMAIL=someonewhodoesnotexist@tutanota.de:mailto:someonewhodoesnotexist@tutanota.de:

I think this is invalid format. We could handle it when importing the event if there are actual users that try to import such events?
In such a case we can modify parseCalendarEvents() to check that what parseMailtoValue() returned is a valid mail address. However, I have concerns about throwing an error and not parsing the event at all. Maybe we could just discard the attendee or organizer whose mail address is in invalid format. I am not sure about the side effects that might have, though.

If you don't think we should handle the invalid format I would propose to close this as wontfix.

[jowlo]

Actually, its an export from our own calendar, here is the original file without changing anything:

BEGIN:VCALENDAR
PRODID:-//Tutao GmbH//Tutanota 3.83.0//EN
VERSION:2.0
CALSCALE:GREGORIAN
METHOD:PUBLISH
BEGIN:VEVENT
DTSTART:20210423T080000Z
DTEND:20210423T083000Z
DTSTAMP:20210423T105406Z
UID:MXBepxk----01asdf00asdf95@tutanota.com
SEQUENCE:2
SUMMARY:testevent4reimport
ORGANIZER;EMAIL=paypaltest@tutanota.com:mailto:paypaltest@tutanota.com
ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=ACCEPTED;RSVP=TRUE;EMAIL=paypaltest@tutanota.com:mailto:paypaltest@tutanota.com
ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP=TRUE;CN="Bedfortest, but with, comma";EMAIL=someonewhodoesnotexist@tutanota.de:mailto:someonewhodoesnotexist@tutanota.de:
END:VEVENT
END:VCALENDAR

It is however a reimport where i changed stuff in the ics file earlier. I guess we shouldn't import it in the first place, catch that error somehow or sanitize the email adresses when importing or exporting.

I don't think won't fix is an option because it does throw an application error after using a normal workflow which imho should never happen. There are a gazillion sources of ics events, pretty sure someone adds malformed mail adresses.

[vaf-hub]

I tried to export and reimport calendars to create an ics files like the one you provided, but there is no trailing colon for the mailto value. So, I am not sure how to reproduce this.

However, I investigated further. There are actually two different errors:

1. If there is a trailing colon in the imported attendee's mail address, upon opening the edit event dialog we receive BadRequestError due to the invalid mail address.

2. If the attendee's mail address is a valid Tutanota mail address (without a trailing colon) but does not exist, we do not immediately get an error upon opening the edit event dialog (as the initial report suggests). We do get an error, though, if we try to delete the event or modify it and try to send out updates to the attendees. So this only happens if we are allowed to send out updates (by being the organizer).

I think we should fix part 2, by allowing the deletion of events with non-existing addresses without showing an error dialog. Regarding updates for modifications of the event I think we should show a confirmation dialog and ask to ignore the non-existing address but send updates to all existing addresses.

[jowlo]

I tried to export and reimport calendars to create an ics files like the one you provided, but there is no trailing colon for the mailto value. So, I am not sure how to reproduce this.

You would have to import a faulty event like one of those i provided first and then export it again. I just meant that we also export it with a colon at the end and do not remove it, so we would need to sanitize at some point.

From the rest of your post it sounds like you were able to reproduce fine though. It think we should definitely fix both errors:

1. If it's not a correctly formatted mail address we shouldn't even do a request to the server. I guess we can import it like we do now but we shouldn't ever expect any calendar event attendee mails to be valid then. Or we deal with this during import (which would be consistent with the fact that we check addresses during creation of a calendar event).
2. We could somehow show the user that the attendee has an invalid mail-address format, maybe with a 'X' icon where now we show the circle or "checkmark in circle" to signal attendee status.

[vaf-hub]

Test notes:

• when importing calendars invalid attendee and organizer mail addresses (like the one above with a trailing colon) are ignored and the event is created without them

create an event with both existing and non-existing valid tutanota mail addresses (by importing a modified ics file)

• verify deletion of the event workls and check that all valid mail addresses do receive an update with the cancellation
• verify that removing all of the invalid addresses and sending updates from the calendar event edit dialog is possible
• verify that modifying the event without removing invalid addresses and sending updates shows an error dialog that mentions the invalid addresses