embedded_asset! panics on unwrap during path manipulation

[bonsairobo]

Bevy version

0.12.0

What you did

pub struct TriplanarMaterialPlugin;

impl Plugin for TriplanarMaterialPlugin {
    fn build(&self, app: &mut App) {
        app.add_plugins(MaterialPlugin::<TriplanarMaterial>::default());

        embedded_asset!(app, "shaders/triplanar.wgsl");
        embedded_asset!(app, "shaders/biplanar.wgsl");
    }
}

What went wrong

thread 'main' panicked at src/plugin.rs:11:9:
called `Option::unwrap()` on a `None` value

Additional information

Root Cause

I believe the root cause it trying to split a path string by "/src/" when the path does not even contain that substring.

Here's the implementation:

macro_rules! embedded_path {
    ($path_str: expr) => {{
        embedded_path!("/src/", $path_str)
    }};

    ($source_path: expr, $path_str: expr) => {{
        let crate_name = module_path!().split(':').next().unwrap();
        let after_src = file!().split($source_path).nth(1).unwrap();
        let file_path = std::path::Path::new(after_src)
            .parent()
            .unwrap()
            .join($path_str);
        std::path::Path::new(crate_name).join(file_path)
    }};
}

This line is where the panic happens:

        let after_src = file!().split($source_path).nth(1).unwrap();

The issue is $source_path = "/src/" while file!() = "src/plugin.rs". Splitting will produce only one element from the iterator, so nth(1) will be None.

Solution

Generally it's a bad idea to do path manipulation with raw strings when you could use Path or PathBuf instead, and I recommend eliminating any use of "/" (it's not portable), e.g. in "/src/". So my suggested solution is to convert strings into PathBuf as soon as possible and do manipulation after that.

[443eb9]

I also find that. A pr about that is open #10379 by me.

[443eb9]

It's such a annoying problem. I spent the whole morning trying to find the source. : (

[MikMikus]

An example, temporary solution if you have problems with linux/windows compilation:

#[cfg(any(not(target_family = "windows"), target_env = "gnu"))]
{
   embedded_asset!(app, "src/", "fonts/Ubuntu-Light.ttf");
}

#[cfg(all(target_family = "windows", not(target_env = "gnu")))]
{
  embedded_asset!(app, "src\\", "fonts\\Ubuntu-Light.ttf");
}