AttributeError: module 'PySide2.QtGui' has no attribute 'QAction' when running on Qt5

[naglis]

Reproduced on Arch Linux when running on Qt5 (Qt5/PySide2 version: 5.15.13 (system-wide)) starting Dangerzone both from source (https://github.com/freedomofpress/dangerzone/commit/8cdb2d572038cda19ab2c53b61abbfb9150fe6f5) and as an installed package (version 0.6.0).

If I am not mistaken, Qt5 is only used on Ubuntu Focal and update checks are disabled by default on Linux, so the probability of users running into it is rather low.

Steps to reproduce:

• In Dangerzone settings.json config file, set updater_check key to true to force update checks and set updated_latest_version key to a version that is higher than the currently installed/used Dangerzone version (e.g. "0.7.0").
• Start Dangerzone GUI from command line (ensure that Qt5 is being used).
• Traceback is printed in the terminal:

  Traceback (most recent call last):
  File "/usr/lib/python3.11/site-packages/dangerzone/gui/main_window.py", line 291, in handle_updates
    success_action = QtGui.QAction("New version available", hamburger_menu)  # type: ignore [attr-defined]
                     ^^^^^^^^^^^^^
  AttributeError: module 'PySide2.QtGui' has no attribute 'QAction'

• Dangerzone window remains functional, the hamburger menu is displaying the hamburger_menu_update_success.svg icon, but the "New version available" menu entry is not displayed.

---

After a quick look at the documentation, it seems that in PySide2 QAction is available under the PySide2.QtWidgets namespace, whereas in PySide6 it resides under PySide6.QtGui. IIUC there are two cases where QAction is used:

https://github.com/freedomofpress/dangerzone/blob/8cdb2d572038cda19ab2c53b61abbfb9150fe6f5/dangerzone/gui/main_window.py#L270 https://github.com/freedomofpress/dangerzone/blob/8cdb2d572038cda19ab2c53b61abbfb9150fe6f5/dangerzone/gui/main_window.py#L291

and the issue would manifest itself if update checking is enabled and there is a new version of there were errors when checking for updates.

A potential fix could be to import QAction directly from the right module based on which Qt version is being used and the use the QAction(...) name directly.

[apyrgio]

Yet another nice dig :star_struck: . Indeed, almost none of our end-users are affected, since updates are disabled by default in Linux. Still, this issue does not affect Ubuntu Focal only. We use Pyside2 in every Debian-based distro, and PySide2 still relies on Qt5 (e.g., see PySide2 dependencies on Debian Trixie).

Given that the gravity of the situation is kinda low, I'd not address it in this particular release. However, your fix makes sense, and we can add it in the next release.