feat: Add component upsert function (#218)

feat: add insert_component script function

Author: makspll

crates/bevy_mod_scripting_core/src/bindings/reference.rs

@@ -221,9 +221,6 @@ impl ReflectReference {
 
     /// The way to access the value of the reference, that is the pointed-to value.
     /// This method is safe to use as it ensures no-one else has aliasing access to the value at the same time.
-    ///
-    /// # Panics
-    /// - if the value is aliased and the access is not allowed
     #[track_caller]
     pub fn with_reflect<O, F: FnOnce(&dyn PartialReflect) -> O>(
         &self,
@@ -241,9 +238,6 @@ impl ReflectReference {
 
     /// The way to access the value of the reference, that is the pointed-to value.
     /// This method is safe to use as it ensures no-one else has aliasing access to the value at the same time.
-    ///
-    /// # Panics
-    /// - if the value is aliased and the access is not allowed
     #[track_caller]
     pub fn with_reflect_mut<O, F: FnOnce(&mut dyn PartialReflect) -> O>(
         &self,

crates/bevy_mod_scripting_core/src/bindings/world.rs

@@ -138,6 +138,16 @@ impl WorldCallbackAccess {
         world.add_default_component(entity, registration)
     }
 
+    pub fn insert_component(
+        &self,
+        entity: Entity,
+        registration: ScriptComponentRegistration,
+        value: ReflectReference,
+    ) -> Result<(), InteropError> {
+        let world = self.try_read()?;
+        world.insert_component(entity, registration, value)
+    }
+
     pub fn get_component(
         &self,
         entity: Entity,
@@ -639,6 +649,39 @@ impl WorldAccessGuard<'_> {
         })
     }
 
+    pub fn insert_component(
+        &self,
+        entity: Entity,
+        registration: ScriptComponentRegistration,
+        value: ReflectReference,
+    ) -> Result<(), InteropError> {
+        let component_data = registration
+            .type_registration()
+            .type_registration()
+            .data::<ReflectComponent>()
+            .ok_or_else(|| {
+                InteropError::missing_type_data(
+                    registration.registration.type_id(),
+                    "ReflectComponent".to_owned(),
+                )
+            })?;
+
+        with_global_access!(self.0.accesses, "Could not insert element", {
+            let type_registry = self.type_registry();
+            let type_registry = type_registry.read();
+            let world_mut = unsafe { self.0.cell.world_mut() };
+            let mut entity = world_mut
+                .get_entity_mut(entity)
+                .map_err(|_| InteropError::missing_entity(entity))?;
+            // TODO: is this fine? creating a new arc here?
+            // Safety: we have global access, we are only accessing the entity and component
+            let ref_ = unsafe { value.reflect_unsafe(Arc::new(self.clone()))? };
+            component_data.apply_or_insert(&mut entity, ref_, &type_registry);
+
+            Ok(())
+        })
+    }
+
     pub fn get_component(
         &self,
         entity: Entity,

crates/bevy_mod_scripting_functions/src/core.rs

@@ -116,6 +116,13 @@ pub fn register_world_functions(reg: &mut World) -> Result<(), FunctionRegistrat
                 w.add_default_component(*e, r.clone())
             },
         )
+        .register(
+            "insert_component",
+            |w: WorldCallbackAccess,
+             e: Val<Entity>,
+             r: Val<ScriptComponentRegistration>,
+             v: ReflectReference| { w.insert_component(*e, r.into_inner(), v) },
+        )
         .register("spawn", |s: WorldCallbackAccess| Ok(Val(s.spawn()?)))
         .register(
             "insert_children",

crates/languages/bevy_mod_scripting_lua/tests/data/insert_component/component_no_default_or_from_world_data_inserts.lua

@@ -0,0 +1,8 @@
+local entity = world.spawn()
+local type = world.get_type_by_name('TestComponent')
+local entity_with_component = world._get_entity_with_test_component('TestComponent')
+local existing_component = world.get_component(entity_with_component, type)
+
+assert(world.has_component(entity, type) == false, 'Expected entity to not have component before adding, test invalid')
+world.insert_component(entity, type, existing_component)
+assert(world.has_component(entity, type) == true, 'Expected entity to have component after adding')

crates/languages/bevy_mod_scripting_lua/tests/data/insert_component/component_with_default_no_component_data_errors.lua

@@ -0,0 +1,8 @@
+local entity = world.spawn()
+local _type = world.get_type_by_name('CompWithDefault')
+local entity_with_component = world._get_entity_with_test_component('CompWithDefault')
+local existing_component = world.get_component(entity_with_component, _type)
+
+assert_throws(function()
+    world.insert_component(entity, _type, existing_component)
+end, "Missing type data ReflectComponent for type: .*CompWithDefault.*")

docs/src/ScriptingReference/world.md

@@ -145,6 +145,24 @@ Arguments:
 world.add_default_component(entity, MyType)
 ```
 
+### insert_component
+
+Inserts or applies the given value to the component of the entity. If the component does not exist it will be added.
+
+Arguments:
+
+| Argument | Type | Description |
+| --- | --- | --- |
+| `entity` | `Entity` | The entity to add the component to |
+| `registration` | `ScriptTypeRegistration` | The type registration as returned by `get_type_by_name` of the component |
+| `component` | `ReflectReference` | A reference to an existing component value to be inserted |
+
+```lua
+local existingComponent = world.get_component(otherEntity, MyType)
+world.insert_component(entity, MyType, existingComponent)
+```
+
+
 ### spawn
 
 Returns: