B0003: Print caller (#14556)

# Objective

B0003 indicates that you tried to act upon a nonexistant entity, but
does not mention where the error occured:
```
2024-07-31T15:46:25.954840Z  WARN bevy_ecs::world: error[B0003]: Could not despawn entity Entity { index: 4294967295, generation: 1 } because it doesn't exist in this World. See: https://bevyengine.org/learn/errors/b0003
```

## Solution

Include caller location:

```
2024-07-31T15:46:25.954840Z  WARN bevy_ecs::world: error[B0003]: src/main.rs:18:11: Could not despawn entity Entity { index: 4294967295, generation: 1 } because it doesn't exist in this World. See: https://bevyengine.org/learn/errors/b0003
```

Open question: What should the exact message format be?

## Testing

None, this doesn't change any logic.

crates/bevy_ecs/src/system/commands/mod.rs

@@ -1,6 +1,5 @@
 mod parallel_scope;
 
-#[cfg(feature = "track_change_detection")]
 use core::panic::Location;
 
 use super::{Deferred, IntoObserverSystem, IntoSystem, RegisterSystem, Resource};
@@ -963,14 +962,16 @@ impl EntityCommands<'_> {
     ///
     /// - [`ComponentId`] must be from the same world as `self`.
     /// - `T` must have the same layout as the one passed during `component_id` creation.
+    #[track_caller]
     pub unsafe fn insert_by_id<T: Send + 'static>(
         &mut self,
         component_id: ComponentId,
         value: T,
     ) -> &mut Self {
+        let caller = Location::caller();
         // SAFETY: same invariants as parent call
         self.add(unsafe {insert_by_id(component_id, value, move |entity| {
-            panic!("error[B0003]: Could not insert a component {component_id:?} (with type {}) for entity {entity:?} because it doesn't exist in this World. See: https://bevyengine.org/learn/errors/#b0003", std::any::type_name::<T>());
+            panic!("error[B0003]: {caller}: Could not insert a component {component_id:?} (with type {}) for entity {entity:?} because it doesn't exist in this World. See: https://bevyengine.org/learn/errors/#b0003", std::any::type_name::<T>());
         })});
         self
     }
@@ -1125,8 +1126,9 @@ impl EntityCommands<'_> {
     /// }
     /// # bevy_ecs::system::assert_is_system(remove_character_system);
     /// ```
+    #[track_caller]
     pub fn despawn(&mut self) {
-        self.add(despawn);
+        self.add(despawn());
     }
 
     /// Pushes an [`EntityCommand`] to the queue, which will get executed for the current [`Entity`].
@@ -1300,14 +1302,17 @@ where
 ///
 /// This won't clean up external references to the entity (such as parent-child relationships
 /// if you're using `bevy_hierarchy`), which may leave the world in an invalid state.
-fn despawn(entity: Entity, world: &mut World) {
+#[track_caller]
-    world.despawn(entity);
+fn despawn() -> impl EntityCommand {
+    let caller = Location::caller();
+    move |entity: Entity, world: &mut World| {
+        world.despawn_with_caller(entity, caller);
+    }
 }
 
 /// An [`EntityCommand`] that adds the components in a [`Bundle`] to an entity.
 #[track_caller]
 fn insert<T: Bundle>(bundle: T) -> impl EntityCommand {
-    #[cfg(feature = "track_change_detection")]
     let caller = core::panic::Location::caller();
     move |entity: Entity, world: &mut World| {
         if let Some(mut entity) = world.get_entity_mut(entity) {
@@ -1317,7 +1322,7 @@ fn insert<T: Bundle>(bundle: T) -> impl EntityCommand {
                 caller,
             );
         } else {
-            panic!("error[B0003]: Could not insert a bundle (of type `{}`) for entity {:?} because it doesn't exist in this World. See: https://bevyengine.org/learn/errors/b0003", std::any::type_name::<T>(), entity);
+            panic!("error[B0003]: {caller}: Could not insert a bundle (of type `{}`) for entity {:?} because it doesn't exist in this World. See: https://bevyengine.org/learn/errors/b0003", std::any::type_name::<T>(), entity);
         }
     }
 }

crates/bevy_ecs/src/world/mod.rs

@@ -55,7 +55,7 @@ use std::{
 
 #[cfg(feature = "track_change_detection")]
 use bevy_ptr::UnsafeCellDeref;
-#[cfg(feature = "track_change_detection")]
+
 use core::panic::Location;
 
 use unsafe_world_cell::{UnsafeEntityCell, UnsafeWorldCell};
@@ -1121,14 +1121,24 @@ impl World {
     /// assert!(world.get_entity(entity).is_none());
     /// assert!(world.get::<Position>(entity).is_none());
     /// ```
+    #[track_caller]
     #[inline]
     pub fn despawn(&mut self, entity: Entity) -> bool {
+        self.despawn_with_caller(entity, Location::caller())
+    }
+
+    #[inline]
+    pub(crate) fn despawn_with_caller(
+        &mut self,
+        entity: Entity,
+        caller: &'static Location,
+    ) -> bool {
         self.flush();
         if let Some(entity) = self.get_entity_mut(entity) {
             entity.despawn();
             true
         } else {
-            warn!("error[B0003]: Could not despawn entity {:?} because it doesn't exist in this World. See: https://bevyengine.org/learn/errors/b0003", entity);
+            warn!("error[B0003]: {caller}: Could not despawn entity {:?} because it doesn't exist in this World. See: https://bevyengine.org/learn/errors/b0003", entity);
             false
         }
     }