For certain fonts, export as svg outputs incorrect svg's, while export as pdf works fine

[Volker-Weissmann]

I downloaded https://fonts.google.com/specimen/Source+Code+Pro and ran this script:

#!/usr/bin/env python
import fontforge
F = fontforge.open("SourceCodePro-Regular.ttf")
for name in F:
    F[name].export(f"pdfs/{name}.pdf")
    F[name].export(f"svgs/{name}.svg")

The pdfs look fine:

Wheres certain svg's are blank:

This is not a bug in my image viewer, the svg's are clearly wrong:

$ cat Beta.svg 
<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd" >
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" viewBox="-10 0 610 1000">
   <g  />
</svg>

Gdb showed me that this suspicious-looking if-branch is taken:

    if ( !svg_sc_any(sc,layer) ) {
	/* I think a space is represented by leaving out the d (path) entirely*/
	/*  rather than having d="" */

I would be thankful if you could fix the issue, but I could also try to write a fix and open a PR, if you would prefer that.

OS: ArchLinux

$ fontforge --version
Copyright (c) 2000-2024. See AUTHORS for Contributors.
 License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
 with many parts BSD <http://fontforge.org/license.html>. Please read LICENSE.
 Version: 20230101
 Based on sources from 2024-04-05 14:41 UTC-ML-D-GDK3.
fontforge 20230101
build date: 2024-04-05 14:41 UTC

[Mercury13]

Solution for you: dereference links beforehand.
Solution for FontForge: add option “export recursively”.