Fedora 43 Issue: Installer crashes when btrfs subvolume gets reformatted while having nested subvolumes

Issue

In Fedora 43, if you run the installer from the desktop Live install media (thus using the “webUI” installer version), it crashes under certain conditions with error:

org.fedoraproject.Anaconda.Error: 'NoneType' object has no attribute 'path'

This error occurs towards the end of the installation. While it might seem “harmless”, because the installed system boots and appears to works, important finalization steps were skipped because of the crash, and it’s not recommended to continue using this system. A new installation should be performed.

https://bugzilla.redhat.com/show_bug.cgi?id=2406198

Cause

This happens when a btrfs subvolume is marked for reformatting (which just means removing it and creating again) while having some nested subvolumes. In the default Fedora installation, that is the case for the root subvolume, which has var/lib/machines nested subvolume. The installer has a bug that causes it to crash when creating a kickstart file towards the end of the installation. Important finalization steps are then missed.

Workarounds

Make sure to remove all nested subvolumes from the subvolume you want to “reformat”, before you start the installation. You can do that using the integrated storage editor in the installer, available from the three-dot menu in the top right corner:

Here’s an example of removing var/lib/machines nested subvolume from the root subvolume: