Crash when trying to remove unavailable source

[jn64]

Describe the bug
Font Manager segfaults when attempting to remove a source that no longer exists. The source is not removed.

To Reproduce
Steps to reproduce the behavior:

1. Add a source in Font Manager e.g. /tmp/foo
2. Delete the source (outside of Font Manager)
3. Restart Font Manager or reload the Sources tab
4. Select the source (now labelled "Source Unavailable") and click the minus button. Font Manager segfaults.

Expected behavior
Remove unavailable source safely.

System Information

• OS: Fedora 41
• Desktop Environment: Xfce
• Font Manager version: 0.9.1 (font-manager-0:0.9.1.20240807-1.x86_64)
• Font Manager installation method: COPR

Additional context
Workaround: recreate the source before removing it in Font Manager, or manually edit ~/.config/font-manager/Sources.xml.

[JerryCasiano]

Thanks for catching and reporting this.

Not clear to me yet why a missing source is causing the path to become null but until I get a little more time the changes in master should eliminate this crash. The update should be available in the COPR repo shortly.

Feel free to re-open if you still have an issue and thanks again.