[Bug]: Creating a Object Masks Zone in UI moves or removes the comment lines in config file when it shouldn't

[sharpcall]

Checklist

• I have updated to the latest available Frigate version.
• I have cleared the cache of my browser.
• I have tried a different browser to see if it is related to my browser.
• I have tried reproducing the issue in incognito mode to rule out problems with any third party extensions or plugins I have installed.
• I have asked the AI at https://docs.frigate.video about my issue.

Describe the problem you are having

I have comments like this above each camera for easy read of cameras. Others may have comments for block portions of their config that may find it nice to have. BUT when one creates a Objec Masks Zone for a camera and draws it on UI, the comments in config.yaml seem to move or disappear. So it misses up the location of the comment.

Comments like below move as a chunk (3 lines in this case) or disappear all together. This probably happens for Masks and Zones too.

########################################
# Right Camera                                                           #
########################################

Steps to reproduce

1. Insert a 3 line comment like I put in description somewhere on top of a camera name. You should have two or three cameras. Put different comments for different camera.
2. Then go to UI and create an Object Masks Zone
3. Restart Frigate and then check config and see your comments moved or disappeared. Repeat this process few times if it doesn't happen and eventually it will happen.
   ...

Version

0.16-2

In which browser(s) are you experiencing the issue with?

No response

Frigate config file

NA

docker-compose file or Docker CLI command

NA

Relevant Frigate log output

NA

Relevant go2rtc log output

NA

Operating system

Debian

Install method

Docker Compose

Network connection

Wired

Camera make and model

NA

Screenshots of the Frigate UI's System metrics pages

NA

Any other information that may be helpful

No response

[inkeep-ai-assistant[bot]]

Based on the available documentation, I cannot find specific information about how the Frigate UI's mask/zone editor handles YAML comments in the configuration file, or any known issues related to comment preservation when using the web-based editor.

The documentation describes how to use the mask/zone creator in the UI(1)(2), but doesn't address the behavior you're experiencing with comments being moved or removed when saving masks or zones through the web interface.

This appears to be a bug with the YAML parser or configuration writer used by Frigate's web UI when it updates the config file. Since this isn't covered in the official documentation, you may want to:

1. Report this as a bug on the Frigate GitHub repository if you haven't already
2. As a workaround, consider manually editing your config.yaml file to add masks and zones using the coordinate format shown in the documentation(1)(2) rather than using the UI editor
3. Keep backups of your config file before using the UI editor

The mask and zone coordinate format is documented(1)(2), so you can add them manually to preserve your comment structure while Frigate addresses this issue.

📚 Sources:

1. Masks
2. Zones

---

Have another question? Just tag @inkeep.

[NickM-27]

This is not a bug we will look to fix, depending on a camera placement and which settings are changed we can not perfectly keep comments consistent. Realistically, this will become less and less of a problem as configuration is moved to the UI.

The comments are not removed, they are just not kept consistent with their position

[sharpcall]

I have a three line comment that gets removed every time I make changes.
Would it not be easy to track comments based on camera starting position like:

camera_1:

Which is indented clearly and has :

[NickM-27]

The comments definitely should not be removed, the yaml library we use maintains comments. But no, comments are much more complicated than they seem to the point where some yaml libraries don't even support them

[hawkeye217]

Right, this isn’t something Frigate can reliably control.

YAML comments aren’t treated as real configuration data. Even though we use one of the best YAML libraries available (ruamel.yaml) that tries to keep comments, it can only attach them loosely to nearby settings.

When the UI updates the config (adds or changes entries), the structure of the file changes, and the library has no way to know exactly where you originally intended a comment to stay. As a result, comments may move or get repositioned.

Preserving exact comment placement would require treating the file like a text editor rather than a config file, which isn’t practical or reliable.

But as @NickM-27 said, comments should definitely not be removed. The library specifically preserves them.