1459758 - Freeze after adding ical calendar with recurring events (holidays)

Status: RESOLVED DUPLICATE of bug 1384198

(Calendar :: General, defect)

Description

[CharlyDelta]

Attachment: holidays.ics

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:59.0) Gecko/20100101 Firefox/59.0
Build ID: 20180323154952

Steps to reproduce:

I uploaded the attached ics calendar to my webserver and then subscribed to it via lightning.

The file is so big because it includes single events for each easter-related holiday. All other holidays which are reasonably sane are recurring events with a corresponding RRULE.


Actual results:

At first all was okay (I also closed and re-opened Thunderbird in the meantime), but then I made an update to the calendar, incremented a sequence number, reuploaded it and shortly after I noticed how my CPU fans started going crazy. Running htop revealed that Thunderbird was at 100% on one core and GNOME then prompted that Thunderbird was not responding.

I then forcefully closed Thunderbird, and since then I am not able to use Lighning anymore. Opening Thunderbird will do nothing, except for one core of my CPU running at 100% (looks like a busy infinite loop). I can only close it forcefully.

Running Thunderbird in --safe-mode works (i.e. to disable Lightning). Running Thunderbird with Lightning disabled works as well.

Running Thunderbird without command line parameters just shows this:

"""
[calBackendLoader] Using Thunderbird's builtin libical backend
"""

Running Thunderbird with --verbose yields:

"""
INFO  -> [[ ... using verbose mode ... ]]
DEBUG -> call '/usr/lib/thunderbird/thunderbird '
[calBackendLoader] Using Thunderbird's builtin libical backend
"""

I am using Debian 9.4 with the default Thunderbird from the package (52.7.0). The same goes for Lightning (5.4.7).

In the meantime: Is there anything I can do to remove the Calendar which causes those issues so that I can at least use Lightning to some limited extend?



Expected results:

Lightning properly updating the Calendar without running into a infinite loop rendering whole Thunderbird unusable

Comment 1

[CharlyDelta]

Attachment: holidays-old.ics

This is the version of the holidays calendar which I had uploaded on the server before I then updated the calendar after which Lightning froze. I don't know if it's relevant.

Comment 2

[Stefan Sitter [:ssitter]]

To temporarily workaround the problem I would close Thunderbird, open the profile folder and edit the calendar.registry settings in prefs.js. You could set calendar.registry.<UID>.disabled to true, or change calendar.registry.<UID>.uri to some other address to prevent Lightning from loading the ics file.

According to diff some recurring rules were changed from BYDAY=SU to BYDAY=1SU, i.e. they never create a valid result. Example

RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=1SU;BYMONTHDAY=11,12,13,14,15,16,17;BYMONTH=12
RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=1SU;BYMONTHDAY=18,19,20,21,22,23,24;BYMONTH=12

First Sunday within December that falls on the 18,19,20,21,22,23,24 day of the month? Not possible.

Therefore this seems to be identical to Bug 1384198.

Comment 3

[CharlyDelta]

Hello Stefan,

you're right, this is indeed a stupid mistake I made. Thank you very much.

It would still be good if Lightning would cause whole Thunderbird to freeze. Considering that there's already a bug for that cause I will close this issue as duplicate.