ViewPiece.qml:105: TypeError: Cannot read property 'sessionName' of null

[SietseAchterop]

Hello list,

I have an app using qml , and running under debian/buster. Please see:
https://github.com/SietseAchterop/RtcNoordApp

On exiting the program that works fine in itself otherwise I get about 10 of the
above messages, of different properties. Always the "of null".
The properties are actually used in the correctly working app.
The problem also happens when I start the program and then immediately close it again.
There probably is something wrong in bringing down the application, but I have no
idea how to tackle this.

I am not aware that I am doing something unusual.
Hopefully someone can point me in a direction.

Thanks in advance, Sietse

[Thomas12345]

Hi,

I'm having the same issue since Qt 5.14. When I quit my app all the properties I exposed to QML via setContextProperty are set to null or undefined and in some way QML tries to access them on exit. It was fine in 5.13.

Thomas

[SietseAchterop]

Now you mention it, I think that's the case here also.
So it could well be a regression.

[Thomas12345]

Hi,

I've created an issue on Qt bug report platform : https://bugreports.qt.io/browse/QTBUG-81247

[Thomas12345]

If you didn't check the QTBUG, the solution is to construct the object you want to expose to QML before the engine itself so they are destroyed after the engine.

[Jim Gir]

I've created all my objects before engine but the bug still occurs if the app stops after less than 5 seconds (approximately)

[Jovan Mitrevski]

The bug was closed, but I still see the problem.

context.setContextProperty("bridge", bridge)
...
engine.load(QtCore.QUrl.fromLocalFile(str(qmlFile)))

I need that order because the bridge provides the data needed in the qml file. But on exit, it seems like the bridge gets closed before the qml file. Any suggestions?

[benjamin.green]

I believe I figured out this issue. I left a comment on the linked bug.