Hi,

Background

When running some Python code from PythonQt the other day, I got a segfault in PythonQtConversion.cpp. It turned out that when an Enum based class is processed by PyObjToQVariant, it's recognised as a sequence (since it's possible to iterate over an Enum in Python), but PySequence_GetItem returns nullptr when the loop gets the value to add to the QVariantList, causing the segfault when calling PyObjToVariant with a null pointer. Unless Enums should be treated in a special way, I assume that the best is to handle them as "normal" classes. In order to do that I created a small patch that checks if val->ob_type->tp_name is "EnumMeta". I'm not sure if this is an acceptable solution, so I'm open for better ways to fix it.

Python 2.7 (with enum34 installed) and 3.6 behave the same.

Files

Supplied files:

pythonqt_run_enum_test.cpp: Minimal application that shows the problem
enumtest.py: Python module with an Enum for use with the test program
handle-enum-when-making-qvariant.diff: My patch

Minimal example

Building

Building the test application (very manual – I ran this on Xubuntu 18.10):

g++ -fPIC -c `pkg-config --cflags Qt5Core python-3.6 PythonQt-Qt5-Python3` -o pythonqt_run_enum_test.o pythonqt_run_enum_test.cpp
g++ -o pythonqt_run_enum_test pythonqt_run_enum_test.o `pkg-config --libs Qt5Core python-3.6 PythonQt-Qt5-Python3`
./pythonqt_run_enum_test

Expected output

Without the patch, there is a segfault when running the minimal example. With the patch applied, it outputs this:

QVariant(QVariantList, (QVariant(QVariantList, (QVariant(QString, "Color"), QVariant(PythonQtObjectPtr, ))), QVariant(QVariantList, (QVariant(QString, "Enum"), QVariant(PythonQtObjectPtr, )))))

Links regarding Enum

Last edit: Erik Lundin 2018-11-21

enumtest.py

handle-enum-when-making-qvariant.diff

pythonqt_run_enum_test.cpp

Segfault when creating QVariant from Enum based Python class

Dynamic Python binding for Qt Applications

Forums

Help

Segfault when creating QVariant from Enum based Python class

Background

Files

Minimal example

Building

Expected output

Links regarding Enum

Segfault when creating QVariant from Enum based Python class

Dynamic Python binding for Qt Applications

Forums

Help

Segfault when creating QVariant from Enum based Python class document.SUBSCRIPTION_OPTIONS = { "thing": "topic", "subscribed": false, "url": "subscribe", "icon": { "css": "fa fa-envelope-o" } };

Background

Files

Minimal example

Building

Expected output

Links regarding Enum

Segfault when creating QVariant from Enum based Python class