(PyQt 6.2.3) Creating a QQmlListProperty will cause access violation on application close (windows)

[Jared Jones]

You can also run that script with PyQt 5.12 and above and get the same
access violation bug when you close the program. On PyQt 5.11 and below,
you can close the program without getting the access violation bug.

-Jared

On Thu, Mar 3, 2022 at 4:16 PM Jared Jones <jared.randall.jones at gmail.com>
wrote:

> No Problem, here is a simple hello world test script:
>
> import sys
>
> from PyQt6.QtWidgets import QApplication, QLabel
> from PyQt6.QtQml import QQmlListProperty
> from PyQt6.QtCore import QObject
> #from pyupdater.client import Client
>
> from config import CLIENT_CONFIG
> from config import UpdatePyUpdaterClientConfig
>
> clientConfig=None
> UpdatePyUpdaterClientConfig(clientConfig)
> app = QApplication(sys.argv)
>
> #this is the troublesome statment:
> QQmlListProperty(QObject, QObject(), [])
>
> #label = QLabel("Hello World!")
> label = QLabel("<font color=red size=40>Hello World!</font>")
>
> label.show()
>
> app.exec()
>
> On Sat, Feb 26, 2022 at 9:18 AM Phil Thompson <phil at riverbankcomputing.com>
> wrote:
>
>> On 11/02/2022 20:44, Jared Jones wrote:
>> > Hi everyone,
>> >
>> > Recently I upgraded an Application in my organization from PyQt 5.5 to
>> > PyQt
>> > 6.2.3. I noticed that after upgrading my application, it would cause a
>> > windows access violation everytime I closed my application. I
>> > eventually
>> > tracked the issue down to the QQmlListProperty() objects in my program.
>> > When the application closes, the underlying QQmlListProperty() objects
>> > (at
>> > the C++ level) do not seem to be deleted, which causes the access
>> > violation. When I removed all QQmlListProperty() objects, my program no
>> > longer throws an Access violation. Even when I have no
>> > QQmlListProperty()
>> > objects in my program, if I drop into pdb, and create a basic
>> > QQmlListProperty() object using the syntax "QQmlListProperty(QObject,
>> > QObject(), [])", and do not assign this object to any python variable,
>> > simply continuing execution after doing this (and then ultimately
>> > closing
>> > my app). will cause an access violation.
>> >
>> > As of right now, there is no way around this bug, except for not using
>> > QQmlListProperty() entirely. QQmlListProperty() cannot be deleted with
>> > sip.delete(), so once the object is created, an access violation WILL
>> > happen when your application closes.There doesn't seem to be any way to
>> > delete an underlying QQmlListProperty() object
>> >
>> > Hopefully, this issue can be resolved in a future release.
>>
>> The next PyQt6 snapshot fixes a bug triggered by...
>>
>> QQmlListProperty(QObject, QObject(), [])
>>
>> ...but the bug is also present in PyQt5 so is unlikely to be the
>> underlying problem. A simple test script would help.
>>
>> Phil
>>
>
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