[PyQt] Simple qml app hanging with PyQt5.7 x86_64 wheel on linux

[Phil Thompson]

On 26 Jul 2016, at 5:54 pm, Russell Warren <russ at perspexis.com> wrote:
> 
> Thanks for the recent 5.7 wheel release, especially the inclusion of QtQuick stuff.
> 
> However, I'm trying a simple hello world application on linux x86_4 (debian 8) and it is hanging.
> 
> Python launcher is a minimal one:
> 
> #!/usr/bin/env python
> import sys
> from PyQt5 import QtGui, QtQml
> 
> app = QtGui.QGuiApplication(sys.argv)
> 
> engine = QtQml.QQmlApplicationEngine()
> engine.load("hello_world.qml")
> 
> sys.exit(app.exec_())
> #EOF
> 
> QML is the stock HelloWorld.qml:
> 
> import QtQuick 2.0
> 
> Rectangle {
>     id: page
>     width: 320; height: 480
>     color: "lightgray"
> 
>     Text {
>         id: helloText
>         text: "Hello world!"
>         y: 30
>         anchors.horizontalCenter: page.horizontalCenter
>         font.pointSize: 24; font.bold: true
>     }
> }
> 
> When executed it just hangs in the Qt event loop (app.exec_()) without displaying anything.
> 
> Here's an strace of it:
> https://goo.gl/Wdp4Xu
> 
> That strace was clipped since the polling just goes on forever.
> 
> Any ideas what is preventing display?  OpenGL is working elsewhere (eg: glxgears runs fine).

I don't think it has anything to with the wheels. It works fine if you use QQuickView. It would be interesting to see what a C++ version of the launcher would do.

Phil