[Merged by Bors] - Redo State architecture

crates/bevy_app/src/app_builder.rs

@@ -5,8 +5,8 @@ use crate::{
     stage, startup_stage, PluginGroup, PluginGroupBuilder,
 };
 use bevy_ecs::{
-    clear_trackers_system, FromResources, IntoExclusiveSystem, IntoSystem, Resource, Resources,
-    RunOnce, Schedule, Stage, StateStage, SystemDescriptor, SystemStage, World,
+    clear_trackers_system, FromResources, IntoExclusiveSystem, IntoSystem, Resources, RunOnce,
+    Schedule, Stage, SystemDescriptor, SystemStage, World,
 };
 use bevy_utils::tracing::debug;
 
@@ -155,39 +155,6 @@ impl AppBuilder {
         self
     }
 
-    pub fn on_state_enter<T: Clone + Resource>(
-        &mut self,
-        stage: &str,
-        state: T,
-        system: impl Into<SystemDescriptor>,
-    ) -> &mut Self {
-        self.stage(stage, |stage: &mut StateStage<T>| {
-            stage.on_state_enter(state, system)
-        })
-    }
-
-    pub fn on_state_update<T: Clone + Resource>(
-        &mut self,
-        stage: &str,
-        state: T,
-        system: impl Into<SystemDescriptor>,
-    ) -> &mut Self {
-        self.stage(stage, |stage: &mut StateStage<T>| {
-            stage.on_state_update(state, system)
-        })
-    }
-
-    pub fn on_state_exit<T: Clone + Resource>(
-        &mut self,
-        stage: &str,
-        state: T,
-        system: impl Into<SystemDescriptor>,
-    ) -> &mut Self {
-        self.stage(stage, |stage: &mut StateStage<T>| {
-            stage.on_state_exit(state, system)
-        })
-    }
-
     pub fn add_default_stages(&mut self) -> &mut Self {
         self.add_stage(
             stage::STARTUP,

crates/bevy_ecs/src/lib.rs

@@ -16,8 +16,8 @@ pub mod prelude {
         resource::{ChangedRes, FromResources, Local, NonSend, Res, ResMut, Resource, Resources},
         schedule::{
             ExclusiveSystemDescriptorCoercion, ParallelSystemDescriptorCoercion,
-            ReportExecutionOrderAmbiguities, RunOnce, Schedule, Stage, State, StateStage,
-            SystemSet, SystemStage,
+            ReportExecutionOrderAmbiguities, RunOnce, Schedule, Stage, State, SystemSet,
+            SystemStage,
         },
         system::{Commands, ExclusiveSystem, IntoExclusiveSystem, IntoSystem, Query, System},
         Added, Bundle, Changed, Component, Entity, Flags, In, IntoChainSystem, Mut, Mutated, Or,