Switch ChildOf back to tuple struct (#18672)

# Objective

In #17905 we swapped to a named field on `ChildOf` to help resolve
variable naming ambiguity of child vs parent (ex: `child_of.parent`
clearly reads as "I am accessing the parent of the child_of
relationship", whereas `child_of.0` is less clear).

Unfortunately this has the side effect of making initialization less
ideal. `ChildOf { parent }` reads just as well as `ChildOf(parent)`, but
`ChildOf { parent: root }` doesn't read nearly as well as
`ChildOf(root)`.

## Solution

Move back to `ChildOf(pub Entity)` but add a `child_of.parent()`
function and use it for all accesses. The downside here is that users
are no longer "forced" to access the parent field with `parent`
nomenclature, but I think this strikes the right balance.

Take a look at the diff. I think the results provide strong evidence for
this change. Initialization has the benefit of reading much better _and_
of taking up significantly less space, as many lines go from 3 to 1, and
we're cutting out a bunch of syntax in some cases.

Sadly I do think this should land in 0.16 as the cost of doing this
_after_ the relationships migration is high.

benches/benches/bevy_ecs/entity_cloning.rs

@@ -155,7 +155,7 @@ fn bench_clone_hierarchy<B: Bundle + Default + GetTypeRegistration>(
 
         for parent in current_hierarchy_level {
             for _ in 0..children {
-                let child_id = world.spawn((B::default(), ChildOf { parent })).id();
+                let child_id = world.spawn((B::default(), ChildOf(parent))).id();
                 hierarchy_level.push(child_id);
             }
         }

crates/bevy_ecs/src/entity/clone_entities.rs

@@ -1337,9 +1337,9 @@ mod tests {
     fn recursive_clone() {
         let mut world = World::new();
         let root = world.spawn_empty().id();
-        let child1 = world.spawn(ChildOf { parent: root }).id();
+        let child1 = world.spawn(ChildOf(root)).id();
-        let grandchild = world.spawn(ChildOf { parent: child1 }).id();
+        let grandchild = world.spawn(ChildOf(child1)).id();
-        let child2 = world.spawn(ChildOf { parent: root }).id();
+        let child2 = world.spawn(ChildOf(root)).id();
 
         let clone_root = world.spawn_empty().id();
         EntityCloner::build(&mut world)

crates/bevy_ecs/src/hierarchy.rs

@@ -54,9 +54,9 @@ use log::warn;
 /// # use bevy_ecs::prelude::*;
 /// # let mut world = World::new();
 /// let root = world.spawn_empty().id();
-/// let child1 = world.spawn(ChildOf { parent: root }).id();
+/// let child1 = world.spawn(ChildOf(root)).id();
-/// let child2 = world.spawn(ChildOf { parent: root }).id();
+/// let child2 = world.spawn(ChildOf(root)).id();
-/// let grandchild = world.spawn(ChildOf { parent: child1 }).id();
+/// let grandchild = world.spawn(ChildOf(child1)).id();
 ///
 /// assert_eq!(&**world.entity(root).get::<Children>().unwrap(), &[child1, child2]);
 /// assert_eq!(&**world.entity(child1).get::<Children>().unwrap(), &[grandchild]);
@@ -96,9 +96,21 @@ use log::warn;
 )]
 #[relationship(relationship_target = Children)]
 #[doc(alias = "IsChild", alias = "Parent")]
-pub struct ChildOf {
+pub struct ChildOf(pub Entity);
+
+impl ChildOf {
     /// The parent entity of this child entity.
-    pub parent: Entity,
+    #[inline]
+    pub fn parent(&self) -> Entity {
+        self.0
+    }
+
+    /// The parent entity of this child entity.
+    #[deprecated(since = "0.16.0", note = "Use child_of.parent() instead")]
+    #[inline]
+    pub fn get(&self) -> Entity {
+        self.0
+    }
 }
 
 // TODO: We need to impl either FromWorld or Default so ChildOf can be registered as Reflect.
@@ -108,9 +120,7 @@ pub struct ChildOf {
 impl FromWorld for ChildOf {
     #[inline(always)]
     fn from_world(_world: &mut World) -> Self {
-        ChildOf {
+        ChildOf(Entity::PLACEHOLDER)
-            parent: Entity::PLACEHOLDER,
-        }
     }
 }
 
@@ -316,7 +326,7 @@ impl<'w> EntityWorldMut<'w> {
     pub fn with_child(&mut self, bundle: impl Bundle) -> &mut Self {
         let parent = self.id();
         self.world_scope(|world| {
-            world.spawn((bundle, ChildOf { parent }));
+            world.spawn((bundle, ChildOf(parent)));
         });
         self
     }
@@ -329,12 +339,9 @@ impl<'w> EntityWorldMut<'w> {
     }
 
     /// Inserts the [`ChildOf`] component with the given `parent` entity, if it exists.
-    #[deprecated(
+    #[deprecated(since = "0.16.0", note = "Use entity_mut.insert(ChildOf(entity))")]
-        since = "0.16.0",
-        note = "Use entity_mut.insert(ChildOf { parent: entity })"
-    )]
     pub fn set_parent(&mut self, parent: Entity) -> &mut Self {
-        self.insert(ChildOf { parent });
+        self.insert(ChildOf(parent));
         self
     }
 }
@@ -394,7 +401,7 @@ impl<'a> EntityCommands<'a> {
     /// [`with_children`]: EntityCommands::with_children
     pub fn with_child(&mut self, bundle: impl Bundle) -> &mut Self {
         let parent = self.id();
-        self.commands.spawn((bundle, ChildOf { parent }));
+        self.commands.spawn((bundle, ChildOf(parent)));
         self
     }
 
@@ -406,12 +413,9 @@ impl<'a> EntityCommands<'a> {
     }
 
     /// Inserts the [`ChildOf`] component with the given `parent` entity, if it exists.
-    #[deprecated(
+    #[deprecated(since = "0.16.0", note = "Use entity_commands.insert(ChildOf(entity))")]
-        since = "0.16.0",
-        note = "Use entity_commands.insert(ChildOf { parent: entity })"
-    )]
     pub fn set_parent(&mut self, parent: Entity) -> &mut Self {
-        self.insert(ChildOf { parent });
+        self.insert(ChildOf(parent));
         self
     }
 }
@@ -427,7 +431,7 @@ pub fn validate_parent_has_component<C: Component>(
         return;
     };
     if !world
-        .get_entity(child_of.parent)
+        .get_entity(child_of.parent())
         .is_ok_and(|e| e.contains::<C>())
     {
         // TODO: print name here once Name lives in bevy_ecs
@@ -527,9 +531,9 @@ mod tests {
     fn hierarchy() {
         let mut world = World::new();
         let root = world.spawn_empty().id();
-        let child1 = world.spawn(ChildOf { parent: root }).id();
+        let child1 = world.spawn(ChildOf(root)).id();
-        let grandchild = world.spawn(ChildOf { parent: child1 }).id();
+        let grandchild = world.spawn(ChildOf(child1)).id();
-        let child2 = world.spawn(ChildOf { parent: root }).id();
+        let child2 = world.spawn(ChildOf(root)).id();
 
         // Spawn
         let hierarchy = get_hierarchy(&world, root);
@@ -550,7 +554,7 @@ mod tests {
         assert_eq!(hierarchy, Node::new_with(root, vec![Node::new(child2)]));
 
         // Insert
-        world.entity_mut(child1).insert(ChildOf { parent: root });
+        world.entity_mut(child1).insert(ChildOf(root));
         let hierarchy = get_hierarchy(&world, root);
         assert_eq!(
             hierarchy,
@@ -638,7 +642,7 @@ mod tests {
     fn self_parenting_invalid() {
         let mut world = World::new();
         let id = world.spawn_empty().id();
-        world.entity_mut(id).insert(ChildOf { parent: id });
+        world.entity_mut(id).insert(ChildOf(id));
         assert!(
             world.entity(id).get::<ChildOf>().is_none(),
             "invalid ChildOf relationships should self-remove"
@@ -650,7 +654,7 @@ mod tests {
         let mut world = World::new();
         let parent = world.spawn_empty().id();
         world.entity_mut(parent).despawn();
-        let id = world.spawn(ChildOf { parent }).id();
+        let id = world.spawn(ChildOf(parent)).id();
         assert!(
             world.entity(id).get::<ChildOf>().is_none(),
             "invalid ChildOf relationships should self-remove"
@@ -661,10 +665,10 @@ mod tests {
     fn reinsert_same_parent() {
         let mut world = World::new();
         let parent = world.spawn_empty().id();
-        let id = world.spawn(ChildOf { parent }).id();
+        let id = world.spawn(ChildOf(parent)).id();
-        world.entity_mut(id).insert(ChildOf { parent });
+        world.entity_mut(id).insert(ChildOf(parent));
         assert_eq!(
-            Some(&ChildOf { parent }),
+            Some(&ChildOf(parent)),
             world.entity(id).get::<ChildOf>(),
             "ChildOf should still be there"
         );
@@ -699,11 +703,11 @@ mod tests {
 
         assert_eq!(
             world.entity(child_a).get::<ChildOf>().unwrap(),
-            &ChildOf { parent }
+            &ChildOf(parent)
         );
         assert_eq!(
             world.entity(child_c).get::<ChildOf>().unwrap(),
-            &ChildOf { parent }
+            &ChildOf(parent)
         );
         assert!(world.entity(child_b).get::<ChildOf>().is_none());
     }
@@ -739,7 +743,7 @@ mod tests {
         assert_eq!(children.0, [child]);
         assert_eq!(
             world.entity(child).get::<ChildOf>().unwrap(),
-            &ChildOf { parent }
+            &ChildOf(parent)
         );
     }
 
@@ -762,11 +766,11 @@ mod tests {
 
         assert_eq!(
             world.entity(child_a).get::<ChildOf>().unwrap(),
-            &ChildOf { parent }
+            &ChildOf(parent)
         );
         assert_eq!(
             world.entity(child_b).get::<ChildOf>().unwrap(),
-            &ChildOf { parent }
+            &ChildOf(parent)
         );
         assert_eq!(
             world.entity(parent).get::<Children>().unwrap().0,
@@ -781,15 +785,15 @@ mod tests {
         );
         assert_eq!(
             world.entity(child_a).get::<ChildOf>().unwrap(),
-            &ChildOf { parent }
+            &ChildOf(parent)
         );
         assert_eq!(
             world.entity(child_c).get::<ChildOf>().unwrap(),
-            &ChildOf { parent }
+            &ChildOf(parent)
         );
         assert_eq!(
             world.entity(child_d).get::<ChildOf>().unwrap(),
-            &ChildOf { parent }
+            &ChildOf(parent)
         );
         assert_eq!(
             world.entity(parent).get::<Children>().unwrap().0,
@@ -844,11 +848,11 @@ mod tests {
 
         assert_eq!(
             world.entity(child_a).get::<ChildOf>().unwrap(),
-            &ChildOf { parent }
+            &ChildOf(parent)
         );
         assert_eq!(
             world.entity(child_b).get::<ChildOf>().unwrap(),
-            &ChildOf { parent }
+            &ChildOf(parent)
         );
         assert_eq!(
             world.entity(parent).get::<Children>().unwrap().0,
@@ -863,11 +867,11 @@ mod tests {
         );
         assert_eq!(
             world.entity(child_c).get::<ChildOf>().unwrap(),
-            &ChildOf { parent }
+            &ChildOf(parent)
         );
         assert_eq!(
             world.entity(child_d).get::<ChildOf>().unwrap(),
-            &ChildOf { parent }
+            &ChildOf(parent)
         );
         assert_eq!(
             world.entity(parent).get::<Children>().unwrap().0,
@@ -974,11 +978,10 @@ mod tests {
         let mut world = World::new();
         let parent = world.spawn_empty().id();
         let other = world.spawn_empty().id();
-        let child = world.spawn(ChildOf { parent }).id();
+        let child = world.spawn(ChildOf(parent)).id();
-        world.entity_mut(child).insert_with_relationship_hook_mode(
+        world
-            ChildOf { parent: other },
+            .entity_mut(child)
-            RelationshipHookMode::Skip,
+            .insert_with_relationship_hook_mode(ChildOf(other), RelationshipHookMode::Skip);
-        );
         assert_eq!(
             &**world.entity(parent).get::<Children>().unwrap(),
             &[child],

crates/bevy_ecs/src/relationship/related_methods.rs

@@ -521,9 +521,9 @@ mod tests {
         let mut world = World::new();
 
         let a = world.spawn_empty().id();
-        let b = world.spawn(ChildOf { parent: a }).id();
+        let b = world.spawn(ChildOf(a)).id();
-        let c = world.spawn(ChildOf { parent: a }).id();
+        let c = world.spawn(ChildOf(a)).id();
-        let d = world.spawn(ChildOf { parent: b }).id();
+        let d = world.spawn(ChildOf(b)).id();
 
         world
             .entity_mut(a)

crates/bevy_input_focus/src/lib.rs

@@ -165,7 +165,7 @@ impl<E: Event + Clone> Traversal<FocusedInput<E>> for WindowTraversal {
 
         // Send event to parent, if it has one.
         if let Some(child_of) = child_of {
-            return Some(child_of.parent);
+            return Some(child_of.parent());
         };
 
         // Otherwise, send it to the window entity (unless this is a window entity).
@@ -338,7 +338,7 @@ impl IsFocused for World {
             if e == entity {
                 return true;
             }
-            if let Some(parent) = self.entity(e).get::<ChildOf>().map(|c| c.parent) {
+            if let Some(parent) = self.entity(e).get::<ChildOf>().map(ChildOf::parent) {
                 e = parent;
             } else {
                 return false;

crates/bevy_input_focus/src/tab_navigation.rs

@@ -375,22 +375,8 @@ mod tests {
         let world = app.world_mut();
 
         let tab_group_entity = world.spawn(TabGroup::new(0)).id();
-        let tab_entity_1 = world
+        let tab_entity_1 = world.spawn((TabIndex(0), ChildOf(tab_group_entity))).id();
-            .spawn((
+        let tab_entity_2 = world.spawn((TabIndex(1), ChildOf(tab_group_entity))).id();
-                TabIndex(0),
-                ChildOf {
-                    parent: tab_group_entity,
-                },
-            ))
-            .id();
-        let tab_entity_2 = world
-            .spawn((
-                TabIndex(1),
-                ChildOf {
-                    parent: tab_group_entity,
-                },
-            ))
-            .id();
 
         let mut system_state: SystemState<TabNavigation> = SystemState::new(world);
         let tab_navigation = system_state.get(world);

crates/bevy_picking/src/events.rs

@@ -92,7 +92,7 @@ where
 
         // Send event to parent, if it has one.
         if let Some(child_of) = child_of {
-            return Some(child_of.parent);
+            return Some(child_of.parent());
         };
 
         // Otherwise, send it to the window entity (unless this is a window entity).

crates/bevy_render/src/view/visibility/mod.rs

@@ -411,7 +411,7 @@ fn visibility_propagate_system(
             Visibility::Hidden => false,
             // fall back to true if no parent is found or parent lacks components
             Visibility::Inherited => child_of
-                .and_then(|c| visibility_query.get(c.parent).ok())
+                .and_then(|c| visibility_query.get(c.parent()).ok())
                 .is_none_or(|(_, x)| x.get()),
         };
         let (_, mut inherited_visibility) = visibility_query
@@ -786,9 +786,7 @@ mod test {
             .entity_mut(parent2)
             .insert(Visibility::Visible);
         // Simulate a change in the parent component
-        app.world_mut()
+        app.world_mut().entity_mut(child2).insert(ChildOf(parent2)); // example of changing parent
-            .entity_mut(child2)
-            .insert(ChildOf { parent: parent2 }); // example of changing parent
 
         // Run the system again to propagate changes
         app.update();

crates/bevy_scene/src/dynamic_scene.rs

@@ -325,7 +325,7 @@ mod tests {
                 .unwrap()
                 .get::<ChildOf>()
                 .unwrap()
-                .parent,
+                .parent(),
             "something about reloading the scene is touching entities with the same scene Ids"
         );
         assert_eq!(
@@ -335,7 +335,7 @@ mod tests {
                 .unwrap()
                 .get::<ChildOf>()
                 .unwrap()
-                .parent,
+                .parent(),
             "something about reloading the scene is touching components not defined in the scene but on entities defined in the scene"
         );
         assert_eq!(
@@ -345,7 +345,7 @@ mod tests {
                 .unwrap()
                 .get::<ChildOf>()
                 .expect("something is wrong with this test, and the scene components don't have a parent/child relationship")
-                .parent,
+                .parent(),
             "something is wrong with this test or the code reloading scenes since the relationship between scene entities is broken"
         );
     }

crates/bevy_scene/src/scene_spawner.rs

@@ -892,30 +892,15 @@ mod tests {
         // Spawn entities with different parent first before parenting them to the actual root, allowing us
         // to decouple child order from archetype-creation-order
         let child1 = scene_world
-            .spawn((
+            .spawn((ChildOf(temporary_root), ComponentA { x: 1.0, y: 1.0 }))
-                ChildOf {
-                    parent: temporary_root,
-                },
-                ComponentA { x: 1.0, y: 1.0 },
-            ))
             .id();
         let child2 = scene_world
-            .spawn((
+            .spawn((ChildOf(temporary_root), ComponentA { x: 2.0, y: 2.0 }))
-                ChildOf {
-                    parent: temporary_root,
-                },
-                ComponentA { x: 2.0, y: 2.0 },
-            ))
             .id();
         // the "first" child is intentionally spawned with a different component to force it into a "newer" archetype,
         // meaning it will be iterated later in the spawn code.
         let child0 = scene_world
-            .spawn((
+            .spawn((ChildOf(temporary_root), ComponentF))
-                ChildOf {
-                    parent: temporary_root,
-                },
-                ComponentF,
-            ))
             .id();
 
         scene_world

crates/bevy_text/src/text.rs

@@ -524,7 +524,7 @@ pub fn detect_text_needs_rerender<Root: Component>(
             ));
             continue;
         };
-        let mut parent: Entity = span_child_of.parent;
+        let mut parent: Entity = span_child_of.parent();
 
         // Search for the nearest ancestor with ComputedTextBlock.
         // Note: We assume the perf cost from duplicate visits in the case that multiple spans in a block are visited
@@ -555,7 +555,7 @@ pub fn detect_text_needs_rerender<Root: Component>(
                 ));
                 break;
             };
-            parent = next_child_of.parent;
+            parent = next_child_of.parent();
         }
     }
 }

crates/bevy_transform/src/helper.rs

@@ -124,7 +124,7 @@ mod tests {
             let mut e = app.world_mut().spawn(transform);
 
             if let Some(parent) = entity {
-                e.insert(ChildOf { parent });
+                e.insert(ChildOf(parent));
             }
 
             entity = Some(e.id());

crates/bevy_transform/src/systems.rs

@@ -53,14 +53,14 @@ pub fn mark_dirty_trees(
 ) {
     for entity in changed_transforms.iter().chain(orphaned.read()) {
         let mut next = entity;
-        while let Ok((parent, mut tree)) = transforms.get_mut(next) {
+        while let Ok((child_of, mut tree)) = transforms.get_mut(next) {
             if tree.is_changed() && !tree.is_added() {
                 // If the component was changed, this part of the tree has already been processed.
                 // Ignore this if the change was caused by the component being added.
                 break;
             }
             tree.set_changed();
-            if let Some(parent) = parent.map(|p| p.parent) {
+            if let Some(parent) = child_of.map(ChildOf::parent) {
                 next = parent;
             } else {
                 break;
@@ -121,7 +121,7 @@ mod serial {
 
             for (child, child_of) in child_query.iter_many(children) {
                 assert_eq!(
-                    child_of.parent, entity,
+                    child_of.parent(), entity,
                     "Malformed hierarchy. This probably means that your hierarchy has been improperly maintained, or contains a cycle"
                 );
                 // SAFETY:
@@ -221,7 +221,7 @@ mod serial {
         let Some(children) = children else { return };
         for (child, child_of) in child_query.iter_many(children) {
             assert_eq!(
-            child_of.parent, entity,
+            child_of.parent(), entity,
             "Malformed hierarchy. This probably means that your hierarchy has been improperly maintained, or contains a cycle"
         );
             // SAFETY: The caller guarantees that `transform_query` will not be fetched for any
@@ -452,7 +452,7 @@ mod parallel {
                         // Static scene optimization
                         return None;
                     }
-                    assert_eq!(child_of.parent, parent);
+                    assert_eq!(child_of.parent(), parent);
 
                     // Transform prop is expensive - this helps avoid updating entire subtrees if
                     // the GlobalTransform is unchanged, at the cost of an added equality check.
@@ -586,8 +586,8 @@ mod test {
         let root = commands.spawn(offset_transform(3.3)).id();
         let parent = commands.spawn(offset_transform(4.4)).id();
         let child = commands.spawn(offset_transform(5.5)).id();
-        commands.entity(parent).insert(ChildOf { parent: root });
+        commands.entity(parent).insert(ChildOf(root));
-        commands.entity(child).insert(ChildOf { parent });
+        commands.entity(child).insert(ChildOf(parent));
         command_queue.apply(&mut world);
         schedule.run(&mut world);
 

crates/bevy_ui/src/experimental/ghost_hierarchy.rs

@@ -150,7 +150,7 @@ impl<'w, 's> UiChildren<'w, 's> {
 
     /// Returns the UI parent of the provided entity.
     pub fn get_parent(&'s self, entity: Entity) -> Option<Entity> {
-        self.parents_query.get(entity).ok().map(|p| p.parent)
+        self.parents_query.get(entity).ok().map(ChildOf::parent)
     }
 
     /// Given an entity in the UI hierarchy, check if its set of children has changed, e.g if children has been added/removed or if the order has changed.

crates/bevy_ui/src/layout/mod.rs

@@ -132,7 +132,7 @@ pub fn ui_layout_system(
                 // Note: This does not cover the case where a parent's Node component was removed.
                 // Users are responsible for fixing hierarchies if they do that (it is not recommended).
                 // Detecting it here would be a permanent perf burden on the hot path.
-                if child_of.is_changed() && !ui_children.is_ui_node(child_of.parent) {
+                if child_of.is_changed() && !ui_children.is_ui_node(child_of.parent()) {
                     warn!(
                         "Node ({entity}) is in a non-UI entity hierarchy. You are using an entity \
 with UI components as a child of an entity without UI components, your UI layout may be broken."

crates/bevy_ui/src/update.rs

@@ -174,7 +174,7 @@ pub fn update_ui_context_system(
     }
 
     for (entity, child_of) in reparented_nodes.iter() {
-        let Ok(computed_target) = computed_target_query.get(child_of.parent) else {
+        let Ok(computed_target) = computed_target_query.get(child_of.parent()) else {
             continue;
         };
 

crates/bevy_winit/src/accessibility.rs

@@ -260,7 +260,7 @@ fn queue_node_for_update(
     window_children: &mut Vec<NodeId>,
 ) {
     let should_push = if let Some(child_of) = child_of {
-        !node_entities.contains(child_of.parent)
+        !node_entities.contains(child_of.parent())
     } else {
         true
     };

examples/3d/mixed_lighting.rs

@@ -460,7 +460,7 @@ fn move_sphere(
     };
 
     // Grab its transform.
-    let Ok(mut transform) = transforms.get_mut(child_of.parent) else {
+    let Ok(mut transform) = transforms.get_mut(child_of.parent()) else {
         return;
     };
 

examples/3d/visibility_range.rs

@@ -187,7 +187,7 @@ fn set_visibility_ranges(
                 break;
             }
             match child_of {
-                Some(child_of) => current = child_of.parent,
+                Some(child_of) => current = child_of.parent(),
                 None => break,
             }
         }

examples/animation/gltf_skinned_mesh.rs

@@ -51,7 +51,7 @@ fn joint_animation(
     // Iter skinned mesh entity
     for child_of in &children {
         // Mesh node is the parent of the skinned mesh entity.
-        let mesh_node_entity = child_of.parent;
+        let mesh_node_entity = child_of.parent();
         // Get `Children` in the mesh node.
         let mesh_node_parent = parents.get(mesh_node_entity).unwrap();
 

examples/tools/scene_viewer/animation_plugin.rs

@@ -107,7 +107,7 @@ fn assign_clips(
                 }
 
                 // Go to the next parent.
-                current = children.get(entity).ok().map(|c| c.parent);
+                current = children.get(entity).ok().map(ChildOf::parent);
             }
         }
 

examples/ui/ghost_nodes.rs

@@ -110,14 +110,14 @@ fn button_system(
     // Update parent counter on click
     for (interaction, child_of) in &mut interaction_query {
         if matches!(interaction, Interaction::Pressed) {
-            let mut counter = counter_query.get_mut(child_of.parent).unwrap();
+            let mut counter = counter_query.get_mut(child_of.parent()).unwrap();
             counter.0 += 1;
         }
     }
 
     // Update button labels to match their parent counter
     for (children, child_of) in &labels_query {
-        let counter = counter_query.get(child_of.parent).unwrap();
+        let counter = counter_query.get(child_of.parent()).unwrap();
         let mut text = text_query.get_mut(children[0]).unwrap();
 
         **text = counter.0.to_string();