Paths won't merge

[MichaelHinrichs]

Describe the bug
When I try to use SVGOMG to merge the paths in the attached SVG, two paths remain unmerged.

To Reproduce

1. Go to https://jakearchibald.github.io/svgomg/
2. Open the attached SVG.
3. Make sure the "Merge Paths' switch is on.
4. Click "Markup" tab.

Expected behavior
All paths merge, leaving only one.

Screenshots

Desktop (please complete the following information):

• SVGO v3.0.0
• Unknown NodeJs Version. Whatever SVGOMG is using.
• OS: Windows 10

Additional context
I'm able to merge the paths with a text editor with no issue. The SVG looks exactly the same, so I'm not sure what's preventing SVGO from doing it. The original file comes from here, as well as others that may replicate the same problem.

[GreLI]

It's not a bug. It's a desirable behavior. Unfortunately, it's not easy to implement. Merging paths can lead to issues like excluding sections. To avoid them one need to check for intersections or even path directions. Currently there is quick and dirty check for convex hulls intersections (by GJK algorithm). If you know a library that can do such a check for paths better than with O(n²) complexity, please let me know.

[adamdiestelkamp]

Running into this too. Sometimes when I export a flattened SVG from Figma I get three paths. These paths don't intersect, but I'd like them to merge into one path (our design system library expects this) but svgo leaves them as 3 paths.

<svg width="24" height="24" viewBox="0 0 24 24" fill="none" xmlns="http://www.w3.org/2000/svg">
<path d="...pathdata" fill="black"/>
<path d="...pathdata" fill="black"/>
<path d="...pathdata" fill="black"/>
</svg>

Is that expected that it won't merge paths that don't touch?

[GreLI]

Yes, if their convex hulls touch.