Changing a material handle doesn't affect how an entity is rendered

[mvlabat]

An example where this can be reproduced: https://github.com/mvlabat/muddle-run/blob/b2fc5d91a6b6d81ee94029924507db0acdedc42d/bins/desktop_client/src/main.rs.

This is where I define two different materials: https://github.com/mvlabat/muddle-run/blob/b2fc5d91a6b6d81ee94029924507db0acdedc42d/bins/desktop_client/src/main.rs#L55-L70

And this is the code where I swap the handles: https://github.com/mvlabat/muddle-run/blob/b2fc5d91a6b6d81ee94029924507db0acdedc42d/bins/desktop_client/src/main.rs#L328-335

I can see the logs printed, so I'm pretty certain that those branches are executed as expected. I also tried inserting debug logging of the material handles themselves, and I could see that they are changed too and no system changes them back somewhere in the middle.

@memoryruins suggested me in the Discord that I try to edit the material itself, like so:

if let Some((material, _)) = controllable_object {
    materials.get_mut(material.clone()).unwrap().albedo = if contacting {
        Color::rgb(0.85, 0.1, 0.1)
    } else {
        Color::rgb(0.87, 0.87, 0.87)
    };
}

After applying these changes, I could see the object rendered in different colours.

My guess is that Bevy's renderer doesn't detect changes in entities' material handles, so this is probably a bug.