.exclusive_system() with .after()

[lukors]

If I use .exclusive_system() together with .after(), Bevy seems unable to find the label I put in .after(). Why is this?

The warning I get is something like WARN bevy_ecs::schedule::graph_utils: my_project::my_file::my_system wants to be after unknown label: MyLabel.

The code looks something like this:

fn build(&self, app: &mut App) {
    app.add_system_to_stage(
            CoreStage::Update,
            my_system.exclusive_system()
            .label(CustomStage::Apply)
            .after(CustomStage::MyLabel),
        );
}

Can exclusive systems not be after a certain label? Or do I need to do something different? Or is there something else going on?

[hymm]

This could be 1 of 2 problems

1. labels belong to a stage, so cannot be used across stages
2. labeling between exclusive and parallel systems is not allowed. If you want to order exclusive systems with parallel systems use the at_start, before_commands, at_end exclusive system modifiers. https://docs.rs/bevy/latest/bevy/ecs/system/struct.ExclusiveSystemFn.html#method.at_start

[lukors]

That's it, that labelling between exclusive and parallel systems is not allowed. I have no other exclusive system with that label, so that's why I'm getting the warning. Thanks a lot for the great answer! 😄