remove conditional sub states

Signed-off-by: lee-orr <lee-orr@users.noreply.github.com>

crates/bevy_app/src/app.rs

@@ -360,66 +360,6 @@ impl App {
  self
  }
 
- /// Sets up a state `S: States` that will only exist when the `Parent: States` state's matches
- /// the provided condition. Creates an instance of [`apply_state_transition::<S>`] in
- /// [`StateTransition`] so that transitions happen before [`Update`](crate::Update), as
- /// well as instances of [`initialize_state_and_enter::<S>`] and [`remove_state_from_world::<S>`]
- /// to set up and run [`OnEnter`] and [`OnExit`] schedules for `S` when appropriate.
- ///
- /// Whenever the parent enters a matching state, `S` will be set to `S::default()`.
- ///
- /// In addition, adds an instance of [`apply_state_transition::<S>`] in
- /// [`StateTransition`] so that transitions happen before [`Update`](crate::Update).
- ///
- /// You can treat these just like any other states, but bear in mind that the `State<S>` and `NextState<S>`
- /// resources might not exist.
- pub fn add_sub_state<S: States, Parent: States>(
- &mut self,
- condition: impl StateMatcher<Parent>,
- ) -> &mut Self {
- self.add_systems(
- Parent::on_enter_matching(condition.clone()),
- initialize_state_and_enter::<S>,
- )
- .add_systems(
- Parent::on_exit_matching(condition.clone()),
- remove_state_from_world::<S>,
- )
- .add_systems(
- StateTransition,
- apply_state_transition::<S>.run_if(in_state(condition)),
- );
-
- self
- }
-
- /// Adds a [`State<S>`] and [`NextState<S>`] whenever entering a matching `Parent` state
- /// regardless of whether the previous `Parent` state matches, and runs OnEnter/OnExit when those occur.
- ///
- /// In addition, adds an instance of [`apply_state_transition::<S>`] in
- /// [`StateTransition`] so that transitions happen before [`Update`](crate::Update).
- ///
- /// You can treat these just like any other states, but bear in mind that the `State<S>` and `NextState<S>`
- /// resources might not exist.
- pub fn add_strict_sub_state<S: States, Parent: States>(
- &mut self,
- condition: impl StateMatcher<Parent>,
- ) -> &mut Self {
- self.add_systems(
- Parent::on_enter_matching_strict(condition.clone()),
- initialize_state_and_enter::<S>,
- )
- .add_systems(
- Parent::on_enter_matching_strict(condition.clone()),
- remove_state_from_world::<S>,
- )
- .add_systems(
- StateTransition,
- apply_state_transition::<S>.run_if(in_state(condition)),
- );
- self
- }
-
  /// Adds a system to the given schedule in this app's [`Schedules`].
  ///
  /// # Examples

crates/bevy_ecs/src/schedule/state.rs

@@ -464,44 +464,6 @@ impl<S: States> NextState<S> {
  }
 }
 
-/// If the state doesn't exist, initializes it to default runs `OnEnter`
-pub fn initialize_state_and_enter<S: States>(world: &mut World) {
- world.insert_resource(NextState::<S>::Keep);
-
- if world.contains_resource::<State<S>>() {
- return;
- }
-
- let default = S::default();
-
- world.insert_resource(State(default.clone()));
-
- world.try_run_schedule(OnEnter(default)).ok();
- world
- .try_run_schedule(OnStateEntry::<S>(PhantomData::<S>))
- .ok();
-}
-
-/// If the state exists, removes it and runs `OnExit`
-pub fn remove_state_from_world<S: States>(world: &mut World) {
- world.remove_resource::<NextState<S>>();
-
- let Some(state) = world.get_resource::<State<S>>() else {
- return;
- };
- let state = state.0.clone();
-
- world.remove_resource::<State<S>>();
-
- world.insert_resource(PreviousState(state.clone()));
-
- world.try_run_schedule(OnExit(state)).ok();
- world
- .try_run_schedule(OnStateExit::<S>(PhantomData::<S>))
- .ok();
- world.remove_resource::<PreviousState<S>>();
-}
-
 /// Run the enter schedule (if it exists) for the current state.
 pub fn run_enter_schedule<S: States>(world: &mut World) {
  let Some(state) = world.get_resource::<State<S>>().map(|s| s.0.clone()) else {