Bug 509712

Opening the subtitle track once causes a backup to be created every time the project is reopened.

Summary
When opening a project and saving it for the first time, a message appears:
"Your project file was modified by Kdenlive. To ensure you don't lose data, a backup copy called..."
and a file named ProjectName_backup0.kdenlive is created.
However, nothing has actually been modified, so it's annoying that a new backup (backup0, backup1, backup2...) is created every time the project is opened.

Steps to Reproduce
1. Open the subtitle track by clicking "Edit Subtitle Tool" or similar.
2. A file named ProjectName.kdenlive.ass is created in the same directory as the project.
3. Delete the .ass file.

Observed Result
Same as in the summary. As an indicator, the project will have a * symbol in the title bar, indicating that it is unsaved, from the moment it is opened.

Expected Result
The program doesn't handle the missing .ass file correctly. It should either remove the subtitle track entirely or create a new .ass file.
Alternatively, it should behave like when a clip is missing, instead of trying to automatically fix it.

This isn't directly related to the bug, but it seems strange that it's impossible to have zero subtitle tracks.
Similarly, it's strange that even if all the text is deleted, the last text remains when the file is opened again, making it impossible to have an empty subtitle file.

Software/OS Version
Kdenlive: 25.08.0
Package Type: Unknown/Default
MLT: 7.33.0
Qt: 6.8.3 (built against 6.8.3 x86_64-little_endian-llp64)
Frameworks: 6.17.0
System: Windows 11 Version 24H2
Kernel: winnt 10.0.26100
CPU: x86_64
Windowing System: windows
GPU: 
Movit (GPU): disabled
Track Compositing: qtblend

Other Information
As a workaround, you can open the .kdenlive file with a text editor, delete the `<property name="kdenlive:sequenceproperties.subtitlesList">...</property>` section, and then never open the subtitle track again.
This isn't urgent, but I thought this strange behavior was a bug, so I'm reporting it.
Thinking about it, maybe I'm at fault for deleting the .ass file.


This was translated using Google Translate. Sorry if it's hard to read.
Thank you.