set_font_families not working on linux

[MeetWq]

os: ubuntu 22.04
skia-safe version:

skia-safe = { version = "0.72.0", features = ["default", "textlayout"] }

I'm trying to set the font families in a paragraph, but it falls back to another font.
FontMgr.match_family_style finds the font, but FontCollection.find_typefaces does not.
I tried to run it on windows and was able to set the font families properly.

use skia_safe::{
    textlayout::{FontCollection, ParagraphBuilder, ParagraphStyle, TextStyle},
    FontMgr, FontStyle,
};

fn main() {
    let mut font_collection = FontCollection::new();
    font_collection.set_default_font_manager(FontMgr::new(), None);
    let family_name = "Ubuntu";
    let style = FontStyle::normal();
    println!(
        "match_family_style: {:?}",
        FontMgr::new()
            .match_family_style(family_name, style)
            .unwrap()
            .family_name()
    );
    println!(
        "find_typefaces: {:?}",
        font_collection.find_typefaces(&[family_name], style)[0].family_name()
    );

    let paragraph_style = ParagraphStyle::new();
    let mut paragraph_builder = ParagraphBuilder::new(&paragraph_style, &font_collection);
    let mut ts = TextStyle::new();
    ts.set_font_families(&[family_name]);
    paragraph_builder.push_style(&ts);
    paragraph_builder.add_text("test");
    let mut paragraph = paragraph_builder.build();
    paragraph.layout(100.0);
    for font_info in paragraph.get_fonts() {
        println!("font_info: {:?}", font_info.font.typeface().family_name());
    }
}

output:

match_family_style: "Ubuntu"
find_typefaces: "Noto Sans CJK SC"
font_info: "Noto Sans CJK SC"

[pragmatrix]

I've installed a Ubuntu 22.04 in a container, installed Rust, libfontconfig1-dev, gcc, g++, git, curl, and fonts-ubuntu, and the output is:

match_family_style: "Ubuntu"
find_typefaces: "Ubuntu"
font_info: "Ubuntu"

after installing fonts-noto-cjk it stays the same. I am not sure why this happens.

[MeetWq]

I found out it's the locales setting causing it.
Previously the global default locale is

LANG=zh_CN.UTF-8

After I set it to English, it works.

export LANG=en_US.UTF-8

But I'm confused why locale affects this.

[pragmatrix]

Nice find!

Even though it is most likely an upstream Skia problem, I'd like to keep this issue open until it's clarified if it should behaving this way and why that is.