The new auto-update functionality causes Ubuntu builds to segfault

[aussig]

On Linux (testing on Ubuntu, both 18 and 19 and the Elementary OS derivative) the application crashes hard if the version check results in no newer version available (i.e. KajuUpdateWindow is not shown). If it shows the window, even if the process is cancelled, there are no problems.

It causes an immediate CTD whether running through the remote debugger or not, with no exception thrown. If run from the command line it reports a Segmentation fault (core dumped)

Analysing the core dump with gdb gives the following:

Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00007f5c220bea31 in ?? ()
   from /home/parallels/OpenSceneryX Installer/OpenSceneryX Installer Libs/XojoGUIFramework64.so
[Current thread is 1 (Thread 0x7f5c244dfa80 (LWP 27056))]

or:

Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x000000000237b780 in ?? ()
[Current thread is 1 (Thread 0x7fbd16ebda80 (LWP 28063))]

or:

Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00007f5c2b5f0c60 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
[Current thread is 1 (Thread 0x7f5c2e070a80 (LWP 28543))]

Tried putting breakpoints in various places throughout the UpdateChecker class and it appears to get through the Async fetch, parse and finishes cleanly. At some point after that the crash occurs.

Reported to Xaju support: Feedback ID 59800