use dedicated blanket trait for state data

Author: Frizi

crates/bevy_app/src/app_builder.rs

@@ -7,13 +7,13 @@ use bevy_ecs::{
     component::ComponentDescriptor,
     event::Events,
     schedule::{
-        RunOnce, Schedule, Stage, StageLabel, State, SystemDescriptor, SystemSet, SystemStage,
+        RunOnce, Schedule, Stage, StageLabel, State, StateData, SystemDescriptor, SystemSet,
+        SystemStage,
     },
     system::{IntoExclusiveSystem, IntoSystem, Resource},
     world::{FromWorld, World},
 };
 use bevy_utils::tracing::debug;
-use std::{fmt::Debug, hash::Hash};
 
 /// Configure [App]s using the builder pattern
 pub struct AppBuilder {
@@ -252,7 +252,7 @@ impl AppBuilder {
     /// adding [State::get_driver] to additional stages you need it in.
     pub fn add_state<T>(&mut self, initial: T) -> &mut Self
     where
-        T: Resource + Debug + Clone + Eq + Hash,
+        T: StateData,
     {
         self.add_state_to_stage(CoreStage::Update, initial)
     }
@@ -264,7 +264,7 @@ impl AppBuilder {
     /// stages you need it in.
     pub fn add_state_to_stage<T>(&mut self, stage: impl StageLabel, initial: T) -> &mut Self
     where
-        T: Resource + Debug + Clone + Eq + Hash,
+        T: StateData,
     {
         self.insert_resource(State::new(initial))
             .add_system_set_to_stage(stage, State::<T>::get_driver())

crates/bevy_ecs/src/schedule/state.rs

@@ -3,11 +3,14 @@ use crate::{
         RunCriteriaDescriptor, RunCriteriaDescriptorCoercion, RunCriteriaLabel, ShouldRun,
         SystemSet,
     },
-    system::{In, IntoChainSystem, IntoSystem, Local, Res, ResMut, Resource},
+    system::{In, IntoChainSystem, IntoSystem, Local, Res, ResMut},
 };
 use std::{any::TypeId, fmt::Debug, hash::Hash};
 use thiserror::Error;
 
+pub trait StateData: Send + Sync + Clone + Eq + Debug + Hash + 'static {}
+impl<T> StateData for T where T: Send + Sync + Clone + Eq + Debug + Hash + 'static {}
+
 /// ### Stack based state machine
 ///
 /// This state machine has four operations: Push, Pop, Set and Replace.
@@ -16,15 +19,15 @@ use thiserror::Error;
 /// * Set replaces the active state with a new one
 /// * Replace unwinds the state stack, and replaces the entire stack with a single new state
 #[derive(Debug)]
-pub struct State<T: Resource + Clone + Eq> {
+pub struct State<T: StateData> {
     transition: Option<StateTransition<T>>,
     stack: Vec<T>,
     scheduled: Option<ScheduledOperation<T>>,
     end_next_loop: bool,
 }
 
 #[derive(Debug)]
-enum StateTransition<T: Resource + Clone + Eq> {
+enum StateTransition<T: StateData> {
     PreStartup,
     Startup,
     // The parameter order is always (leaving, entering)
@@ -36,7 +39,7 @@ enum StateTransition<T: Resource + Clone + Eq> {
 }
 
 #[derive(Debug)]
-enum ScheduledOperation<T: Resource + Clone + Eq> {
+enum ScheduledOperation<T: StateData> {
     Set(T),
     Replace(T),
     Pop,
@@ -57,7 +60,7 @@ enum StateCallback {
 impl StateCallback {
     fn into_label<T>(self, state: T) -> StateRunCriteriaLabel<T>
     where
-        T: Resource + Debug + Clone + Eq + Hash,
+        T: StateData,
     {
         StateRunCriteriaLabel(state, self)
     }
@@ -67,7 +70,7 @@ impl StateCallback {
 struct StateRunCriteriaLabel<T>(T, StateCallback);
 impl<T> RunCriteriaLabel for StateRunCriteriaLabel<T>
 where
-    T: Resource + Debug + Clone + Eq + Hash,
+    T: StateData,
 {
     fn dyn_clone(&self) -> Box<dyn RunCriteriaLabel> {
         Box::new(self.clone())
@@ -90,7 +93,7 @@ impl DriverLabel {
 
 impl<T> State<T>
 where
-    T: Resource + Debug + Clone + Eq + Hash,
+    T: StateData,
 {
     pub fn on_update(s: T) -> RunCriteriaDescriptor {
         (|state: Res<State<T>>, pred: Local<Option<T>>| {
@@ -393,10 +396,7 @@ pub enum StateError {
     StackEmpty,
 }
 
-fn should_run_adapter<T: Resource + Clone + Eq>(
-    In(cmp_result): In<bool>,
-    state: Res<State<T>>,
-) -> ShouldRun {
+fn should_run_adapter<T: StateData>(In(cmp_result): In<bool>, state: Res<State<T>>) -> ShouldRun {
     if state.end_next_loop {
         return ShouldRun::No;
     }
@@ -407,7 +407,7 @@ fn should_run_adapter<T: Resource + Clone + Eq>(
     }
 }
 
-fn state_cleaner<T: Resource + Clone + Eq>(
+fn state_cleaner<T: StateData>(
     mut state: ResMut<State<T>>,
     mut prep_exit: Local<bool>,
 ) -> ShouldRun {

crates/bevy_ecs/src/schedule/system_set.rs

@@ -1,11 +1,7 @@
-use crate::{
-    schedule::{
-        AmbiguitySetLabel, BoxedAmbiguitySetLabel, BoxedSystemLabel, IntoRunCriteria,
-        RunCriteriaDescriptorOrLabel, State, SystemDescriptor, SystemLabel,
-    },
-    system::Resource,
+use crate::schedule::{
+    AmbiguitySetLabel, BoxedAmbiguitySetLabel, BoxedSystemLabel, IntoRunCriteria,
+    RunCriteriaDescriptorOrLabel, State, StateData, SystemDescriptor, SystemLabel,
 };
-use std::{fmt::Debug, hash::Hash};
 
 /// A builder for describing several systems at the same time.
 pub struct SystemSet {
@@ -37,49 +33,49 @@ impl SystemSet {
 
     pub fn on_update<T>(s: T) -> SystemSet
     where
-        T: Resource + Debug + Clone + Eq + Hash,
+        T: StateData,
     {
         Self::new().with_run_criteria(State::<T>::on_update(s))
     }
 
     pub fn on_inactive_update<T>(s: T) -> SystemSet
     where
-        T: Resource + Debug + Clone + Eq + Hash,
+        T: StateData,
     {
         Self::new().with_run_criteria(State::<T>::on_inactive_update(s))
     }
 
     pub fn on_in_stack_update<T>(s: T) -> SystemSet
     where
-        T: Resource + Debug + Clone + Eq + Hash,
+        T: StateData,
     {
         Self::new().with_run_criteria(State::<T>::on_in_stack_update(s))
     }
 
     pub fn on_enter<T>(s: T) -> SystemSet
     where
-        T: Resource + Debug + Clone + Eq + Hash,
+        T: StateData,
     {
         Self::new().with_run_criteria(State::<T>::on_enter(s))
     }
 
     pub fn on_exit<T>(s: T) -> SystemSet
     where
-        T: Resource + Debug + Clone + Eq + Hash,
+        T: StateData,
     {
         Self::new().with_run_criteria(State::<T>::on_exit(s))
     }
 
     pub fn on_pause<T>(s: T) -> SystemSet
     where
-        T: Resource + Debug + Clone + Eq + Hash,
+        T: StateData,
     {
         Self::new().with_run_criteria(State::<T>::on_pause(s))
     }
 
     pub fn on_resume<T>(s: T) -> SystemSet
     where
-        T: Resource + Debug + Clone + Eq + Hash,
+        T: StateData,
     {
         Self::new().with_run_criteria(State::<T>::on_resume(s))
     }