Trying to access array offset on value of type bool

[Yenya]

Baikal version: 0.7.1

Current behaviour:
After upgrading to 0.7.1, some HTTP requests fail with 500 internal server error, and in my php error log, the following backtrace is logged:

[15-Jun-2020 19:19:26 Europe/Prague] ErrorException: Trying to access array offset on value of type bool in /var/www/baikal-0.7.1/vendor/sabre/dav/lib/CalDAV/Backend/PDO.php:791
Stack trace:
#0 /var/www/baikal-0.7.1/vendor/sabre/dav/lib/CalDAV/Backend/PDO.php(791): Baikal\Framework::exception_error_handler()
#1 /var/www/baikal-0.7.1/vendor/sabre/dav/lib/CalDAV/Calendar.php(354): Sabre\CalDAV\Backend\PDO->calendarQuery()
#2 /var/www/baikal-0.7.1/vendor/sabre/dav/lib/CalDAV/Plugin.php(598): Sabre\CalDAV\Calendar->calendarQuery()
#3 /var/www/baikal-0.7.1/vendor/sabre/dav/lib/CalDAV/Plugin.php(258): Sabre\CalDAV\Plugin->calendarQueryReport()
#4 /var/www/baikal-0.7.1/vendor/sabre/event/lib/WildcardEmitterTrait.php(89): Sabre\CalDAV\Plugin->report()
#5 /var/www/baikal-0.7.1/vendor/sabre/dav/lib/DAV/CorePlugin.php(685): Sabre\DAV\Server->emit()
#6 /var/www/baikal-0.7.1/vendor/sabre/event/lib/WildcardEmitterTrait.php(89): Sabre\DAV\CorePlugin->httpReport()
#7 /var/www/baikal-0.7.1/vendor/sabre/dav/lib/DAV/Server.php(470): Sabre\DAV\Server->emit()
#8 /var/www/baikal-0.7.1/vendor/sabre/dav/lib/DAV/Server.php(251): Sabre\DAV\Server->invokeMethod()
#9 /var/www/baikal-0.7.1/vendor/sabre/dav/lib/DAV/Server.php(319): Sabre\DAV\Server->start()
#10 /var/www/baikal-0.7.1/Core/Frameworks/Baikal/Core/Server.php(119): Sabre\DAV\Server->exec()
#11 /var/www/baikal-0.7.1/html/cal.php(74): Baikal\Core\Server->start()
#12 {main}

From the HTTP access_log:
client.ip.addr - - [15/Jun/2020:19:19:26 +0200] "REPORT /cal/cal.php/calendars/kas/default/ HTTP/1.1" 207 9266 "-" "Evolution/3.36.2"
client.ip.addr - - [15/Jun/2020:19:19:26 +0200] "REPORT /cal/cal.php/calendars/kas/default/ HTTP/1.1" 500 278 "-" "Evolution/3.36.2"

So some requests work and some crash.

I don't know how to reproduce this without publishing my db.sqlite (which I obviously don't want to do).

FWIW, I have been synchronizing this particular Evolution client against Baikal for many years now, but I had Baikal 0.4.6 till about a week ago. I wanted to move to a modern version of Baikal, so I upgraded first to 0.5.3, then to 0.7.0, and today to 0.7.1. It might be that some old data were not converted correctly during these upgrades. I also synchronize the same account to my phone (SailfishOS/Jolla), both for calendar and contacts, but I see 500 internal server error only from Evolution.

[Tntdruid]

Use the Issue template.

Same as #929?

[Yenya]

Yep, it might be the same as #929 - I use Fedora 32, which has php-7.4.6.

[DeepDiver1975]

close as dup