Revert Align Scene::write_to_world_with to match DynamicScene::write_to_world_with (#13800)

# Objective

- https://github.com/bevyengine/bevy/pull/13714 broke scenes pretty
seriously
- Fixes https://github.com/bevyengine/bevy/issues/13796

## Solution

Revert it. We can redo this PR once the behavior is fixed.

Co-authored-by: Dmytro Banin <dima_banin@hotmail.com>

crates/bevy_scene/src/scene.rs

@@ -1,6 +1,6 @@
-use crate::{DynamicScene, SceneSpawnError};
+use crate::{DynamicScene, InstanceInfo, SceneSpawnError};
 use bevy_asset::Asset;
-use bevy_ecs::entity::{Entity, EntityHashMap};
+use bevy_ecs::entity::EntityHashMap;
 use bevy_ecs::{
     reflect::{AppTypeRegistry, ReflectComponent, ReflectMapEntities, ReflectResource},
     world::World,
@@ -43,8 +43,7 @@ impl Scene {
     /// provided [`AppTypeRegistry`] or doesn't reflect the [`Component`](bevy_ecs::component::Component) trait.
     pub fn clone_with(&self, type_registry: &AppTypeRegistry) -> Result<Scene, SceneSpawnError> {
         let mut new_world = World::new();
-        let mut entity_map = EntityHashMap::default();
-        self.write_to_world_with(&mut new_world, &mut entity_map, type_registry)?;
+        self.write_to_world_with(&mut new_world, type_registry)?;
         Ok(Self { world: new_world })
     }
 
@@ -55,9 +54,12 @@ impl Scene {
     pub fn write_to_world_with(
         &self,
         world: &mut World,
-        entity_map: &mut EntityHashMap<Entity>,
         type_registry: &AppTypeRegistry,
-    ) -> Result<(), SceneSpawnError> {
+    ) -> Result<InstanceInfo, SceneSpawnError> {
+        let mut instance_info = InstanceInfo {
+            entity_map: EntityHashMap::default(),
+        };
+
         let type_registry = type_registry.read();
 
         // Resources archetype
@@ -92,7 +94,8 @@ impl Scene {
 
         for archetype in self.world.archetypes().iter() {
             for scene_entity in archetype.entities() {
-                let entity = entity_map
+                let entity = *instance_info
+                    .entity_map
                     .entry(scene_entity.id())
                     .or_insert_with(|| world.spawn_empty().id());
                 for component_id in archetype.components() {
@@ -118,7 +121,7 @@ impl Scene {
                         &self.world,
                         world,
                         scene_entity.id(),
-                        *entity,
+                        entity,
                         &type_registry,
                     );
                 }
@@ -127,10 +130,10 @@ impl Scene {
 
         for registration in type_registry.iter() {
             if let Some(map_entities_reflect) = registration.data::<ReflectMapEntities>() {
-                map_entities_reflect.map_all_entities(world, entity_map);
+                map_entities_reflect.map_all_entities(world, &mut instance_info.entity_map);
             }
         }
 
-        Ok(())
+        Ok(instance_info)
     }
 }

crates/bevy_scene/src/scene_spawner.rs

@@ -221,7 +221,6 @@ impl SceneSpawner {
             let scene = scenes
                 .get(id)
                 .ok_or(SceneSpawnError::NonExistentScene { id })?;
-
             scene.write_to_world(world, entity_map)
         })
     }
@@ -230,33 +229,27 @@ impl SceneSpawner {
     pub fn spawn_sync(
         &mut self,
         world: &mut World,
-        id: impl Into<AssetId<Scene>>,
+        id: AssetId<Scene>,
     ) -> Result<InstanceId, SceneSpawnError> {
-        let mut entity_map = EntityHashMap::default();
-        let id = id.into();
-        Self::spawn_sync_internal(world, id, &mut entity_map)?;
-        let instance_id = InstanceId::new();
-        self.spawned_instances
-            .insert(instance_id, InstanceInfo { entity_map });
-        Ok(instance_id)
+        self.spawn_sync_internal(world, id, InstanceId::new())
     }
 
     fn spawn_sync_internal(
-        // &mut self,
+        &mut self,
         world: &mut World,
         id: AssetId<Scene>,
-        entity_map: &mut EntityHashMap<Entity>,
-    ) -> Result<(), SceneSpawnError> {
+        instance_id: InstanceId,
+    ) -> Result<InstanceId, SceneSpawnError> {
         world.resource_scope(|world, scenes: Mut<Assets<Scene>>| {
             let scene = scenes
                 .get(id)
                 .ok_or(SceneSpawnError::NonExistentRealScene { id })?;
 
-            scene.write_to_world_with(
-                world,
-                entity_map,
-                &world.resource::<AppTypeRegistry>().clone(),
-            )
+            let instance_info =
+                scene.write_to_world_with(world, &world.resource::<AppTypeRegistry>().clone())?;
+
+            self.spawned_instances.insert(instance_id, instance_info);
+            Ok(instance_id)
         })
     }
 
@@ -326,9 +319,7 @@ impl SceneSpawner {
         let scenes_to_spawn = std::mem::take(&mut self.scenes_to_spawn);
 
         for (scene_handle, instance_id) in scenes_to_spawn {
-            let mut entity_map = EntityHashMap::default();
-
-            match Self::spawn_sync_internal(world, scene_handle.id(), &mut entity_map) {
+            match self.spawn_sync_internal(world, scene_handle.id(), instance_id) {
                 Ok(_) => {}
                 Err(SceneSpawnError::NonExistentRealScene { .. }) => {
                     self.scenes_to_spawn.push((scene_handle, instance_id));