Avoid crash with read only QgsCheckableComboBox

[m-kuhn]

Reported in the mailing list by @ghtmtt

Hi all,

I'm using a QgsCheckableComboBox in an UI of a plugin. If I use the flag
setEditable = False, bot from UI or from code, QGIS simply explodes
(3.16 from package, 3.23 compiled on a Debian sid OS).

What is strange, at least for me, is that even by using in a python
console the following code, QGIS explodes:

c = QgsCheckableComboBox()
c.setEditable(False)
c.show()

while without the c.setEditable(False) no problem and also the following
code is working nice:

c = QComboBox()
c.setEditable(False)
c.show()

Not sure if it is something related to my system. Should I file a ticket?

Thanks!

The Qt docs say https://doc.qt.io/qt-5/qcombobox.html#lineEdit

Returns the line edit used to edit items in the combobox, or nullptr if there is no line edit.

Only editable combo boxes have a line edit.

[nyalldawson]

Is this easy to catch in a test?

[m-kuhn]

Should be safe to bypass the extra patch release

[nyalldawson]

unrelated CI failure

[ghtmtt]

thanks @m-kuhn for the fix!