Use system type name as default system name

crates/bevy_app/src/schedule_plan.rs

@@ -1,11 +1,12 @@
 use crate::System;
 use legion::prelude::Schedule;
-use std::{cmp::Ordering, collections::HashMap};
+use std::{cmp::Ordering, collections::{HashSet, HashMap}, borrow::Cow};
 
 #[derive(Default)]
 pub struct SchedulePlan {
     stages: HashMap<String, Vec<System>>,
     stage_order: Vec<String>,
+    system_names: HashSet<Cow<'static, str>>,
 }
 
 impl SchedulePlan {
@@ -23,7 +24,7 @@ impl SchedulePlan {
                         System::ThreadLocal(runnable) => {
                             schedule_builder = schedule_builder.add_thread_local(runnable);
                         }
-                        System::ThreadLocalFn(thread_local) => {
+                        System::ThreadLocalFn((_name, thread_local)) => {
                             schedule_builder = schedule_builder.add_thread_local_fn(thread_local);
                         }
                     }
@@ -90,6 +91,12 @@ impl SchedulePlan {
             .stages
             .get_mut(stage_name)
             .unwrap_or_else(|| panic!("Stage does not exist: {}", stage_name));
+        let system = system.into();
+        let system_name = system.name();
+        if self.system_names.contains(&system_name) {
+            panic!("System with name {} already exists", system_name);
+        }
+        self.system_names.insert(system_name);
         systems.push(system.into());
 
         self

crates/bevy_app/src/system.rs

@@ -1,8 +1,19 @@
 use legion::prelude::{Resources, Runnable, Schedulable, World};
+use std::borrow::Cow;
 pub enum System {
     Schedulable(Box<dyn Schedulable>),
     ThreadLocal(Box<dyn Runnable>),
-    ThreadLocalFn(Box<dyn FnMut(&mut World, &mut Resources)>),
+    ThreadLocalFn((&'static str, Box<dyn FnMut(&mut World, &mut Resources)>)),
+}
+
+impl System {
+    pub fn name(&self) -> Cow<'static, str> {
+        match *self {
+            System::Schedulable(ref schedulable) => schedulable.name().name(),
+            System::ThreadLocal(ref runnable) => runnable.name().name(),
+            System::ThreadLocalFn((ref name, ref _thread_local_fn)) => Cow::Borrowed(name),
+        }
+    }
 }
 
 impl From<Box<dyn Schedulable>> for System {
@@ -22,6 +33,6 @@ where
     T: FnMut(&mut World, &mut Resources) + 'static,
 {
     fn from(system: T) -> Self {
-        System::ThreadLocalFn(Box::new(system))
+        System::ThreadLocalFn((std::any::type_name::<T>(), Box::new(system)))
     }
 }

crates/bevy_legion/legion_systems/src/system.rs

@@ -771,6 +771,10 @@ impl SystemId {
             type_id: TypeId::of::<T>(),
         }
     }
+
+    pub fn name(&self) -> Cow<'static, str> {
+        self.name.clone()
+    }
 }
 
 impl std::fmt::Display for SystemId {

crates/bevy_legion/legion_systems/src/system_fn.rs

@@ -14,7 +14,6 @@ use legion_core::{
     storage::ComponentTypeId,
 };
 use std::marker::PhantomData;
-use uuid::Uuid;
 
 pub trait IntoSystem<'a, CommandBuffer, Resources, Components> {
     fn system_id(self, id: SystemId) -> Box<dyn Schedulable>;
@@ -59,8 +58,7 @@ macro_rules! impl_system {
             }
 
             fn system(self) -> Box<dyn Schedulable> {
-                let uuid = Uuid::new_v4();
-                self.system_id(uuid.to_simple().to_string().into())
+                self.system_id(std::any::type_name::<Self>().to_string().into())
             }
         }
     }

crates/bevy_render/src/mesh.rs

@@ -325,7 +325,7 @@ pub fn mesh_batcher_system() -> Box<dyn Schedulable> {
 }
 
 pub fn mesh_specializer_system() -> Box<dyn Schedulable> {
-    SystemBuilder::new("mesh_batcher")
+    SystemBuilder::new("mesh_specializer")
         .read_resource::<AssetStorage<Mesh>>()
         .with_query(
             <(Read<Handle<Mesh>>, Write<Renderable>)>::query()