Avoid crashing when clicking reload

[abdelq]

For context, this was happening to me on macOS with files being written to a temporary directory and no longer existing there. I would attempt to reload with the notification and KLayout would crash instead of giving an error message.

[klayoutmatthias]

Hi @abdelq,

thanks for the PR, but I think it's not the right place to catch exceptions. "reload layout" is part of the script API and it should really throw an exception in case of an error.

I tried to reproduce the problem on Linux, and there is no crash as the exception is caught higher up in the call stack - namely in lay::GuiApplication::do_notify:

So there is a no systematic issue. When you see a crash on MacOS it's likely because there may be an ABI incompatibility between the Qt shared objects and the application code and that prevents throwing exceptions over Qt library boundaries. I had such cases, when the Qt library is built with a different compiler than the application.

This is a general issue and will cause problems in many other places.

If the is absolutely no other solution, you can basically put the BEGIN_PROTECTED ... END_PROTECTED bracket into lay::LayoutViewNotificationWidget::action_triggered (once is enough), but I think this will only solve one problem out of many.

Matthias