SUMMARY

As per title, when there is no space left on krita's home directory partition all manual saves fails silently, meaning without warning or user-directed messages. Error is present in the logs but it is impossible to know the saves failed at all unless the user checks them out themselves.

Autosaves still work, unless the file is not saved in which case the autosave fails too with a short lived message at the bottom of the window.

It is important to note that it is missing space in the home directory and not in the saved file directory (if different) that creates this bug.

Main problem here is that the user should be notified of the problem directly, ideally with a halting popup as the problem is very urgent and requires instant action, instead of keeping the errors hidden in the log. Failing to do so means that the user thinks the saves are working as intended when in fact they are not.

STEPS TO REPRODUCE
1. Create ~600MB empty file, format it as ext4 and mount it
2. Place Krita appimage in mounted file with name "krita"
3. Create "krita.home" directory (to use as home directory)
4. Launch Krita 
5. Fill remaining disk space in the krita partition with data
6. Settings -> Configure Krita -> General -> File Handling -> Backup File Location set to "User Folder"
7. Create a new kra file, add content to make it large enough to not be saved
8. Save the file outside of the mounted directory
9. Edit image, then manually click the save button or hit the save shortcut

OBSERVED RESULT
The save fails silently

EXPECTED RESULT
The program should notify the user that the save failed and prompt them to free space in the home directory's partition

SOFTWARE/OS VERSIONS
Linux: Xubuntu 22.04.1 LTS
Qt Version: 5.12.12