better error handling when rapier context is missing

src/plugin/context/systemparams/rapier_context_access.rs

@@ -127,20 +127,6 @@ impl<'w, 's> RapierContextAccessMut<'w, 's> {
         self.rapier_context.get_mut(link.0).ok()
     }
 
-    /// Retrieves the rapier context component on this [`Entity`].
-    ///
-    /// Calling this method on a rapier managed entity (rigid body, collider, joints...) will fail.
-    /// Given entity should have a [`RapierContext`].
-    ///
-    /// SAFETY: This method will panic if its underlying query fails.
-    pub(crate) fn context_from_entity(
-        &mut self,
-        rapier_context_entity: Entity,
-    ) -> Mut<RapierContext> {
-        self.try_context_from_entity(rapier_context_entity)
-            .unwrap_or_else(|| panic!("entity {rapier_context_entity} has no RapierContext."))
-    }
-
     /// Retrieves the rapier context component on this [`Entity`].
     ///
     /// Calling this method on a rapier managed entity (rigid body, collider, joints...) will fail.
@@ -152,16 +138,3 @@ impl<'w, 's> RapierContextAccessMut<'w, 's> {
         self.rapier_context.get_mut(rapier_context_entity).ok()
     }
 }
-
-/// Gets the default RapierContext.
-///
-/// SAFETY: Panics if no entity with [`DefaultRapierContext`] exist.
-pub fn get_single_context(
-    default_context_access: &Query<Entity, With<DefaultRapierContext>>,
-) -> Entity {
-    default_context_access.get_single().expect(
-        "No entity with `DefaultRapierContext` found.\
-                        Please add a default `RapierContext` or a `RapierContextEntityLink`\
-                        on the new rapier-managed entity.",
-    )
-}

src/plugin/plugin.rs

@@ -304,6 +304,7 @@ pub fn insert_default_world(
         RapierContextInitialization::NoAutomaticRapierContext => {}
         RapierContextInitialization::InitializeDefaultRapierContext { length_unit } => {
             commands.spawn((
+                Name("Rapier Context"),
                 RapierContext {
                     integration_parameters: IntegrationParameters {
                         length_unit: *length_unit,

src/plugin/systems/collider.rs

@@ -1,6 +1,6 @@
 use crate::dynamics::ReadMassProperties;
 use crate::geometry::Collider;
-use crate::plugin::context::systemparams::{get_single_context, RapierEntity};
+use crate::plugin::context::systemparams::RapierEntity;
 use crate::plugin::context::RapierContextEntityLink;
 use crate::plugin::{
     DefaultRapierContext, RapierConfiguration, RapierContext, RapierContextAccessMut,
@@ -344,15 +344,15 @@ pub fn init_colliders(
     mut commands: Commands,
     config: Query<&RapierConfiguration>,
     mut context_access: RapierContextAccessMut,
-    default_context: Query<Entity, With<DefaultRapierContext>>,
+    default_context_access: Query<Entity, With<DefaultRapierContext>>,
     colliders: Query<(ColliderComponents, Option<&GlobalTransform>), Without<RapierColliderHandle>>,
     mut rigid_body_mprops: Query<&mut ReadMassProperties>,
     parent_query: Query<&Parent>,
     transform_query: Query<&Transform>,
 ) {
     for (
         (
-            (entity, context_link),
+            (entity, entity_context_link),
             shape,
             sensor,
             mprops,
@@ -370,22 +370,29 @@ pub fn init_colliders(
         global_transform,
     ) in colliders.iter()
     {
-        let context_entity = context_link.map_or_else(
+        // Get rapier context from RapierContextEntityLink or insert its default value.
+        let context_entity = entity_context_link.map_or_else(
             || {
-                let context_entity = get_single_context(&default_context);
+                let context_entity = default_context_access.get_single().ok()?;
                 commands
                     .entity(entity)
                     .insert(RapierContextEntityLink(context_entity));
-                context_entity
+                Some(context_entity)
             },
-            |link| link.0,
+            |link| Some(link.0),
         );
-        let context = context_access
-            .context_from_entity(context_entity)
-            .into_inner();
+        let Some(context_entity) = context_entity else {
+            continue;
+        };
+
         let config = config.get(context_entity).unwrap_or_else(|_| {
             panic!("Failed to retrieve `RapierConfiguration` on entity {context_entity}.")
         });
+        let Some(context) = context_access.try_context_from_entity(context_entity) else {
+            log::error!("Could not find entity {context_entity} with rapier context while initializing {entity}");
+            continue;
+        };
+        let context = context.into_inner();
         let mut scaled_shape = shape.clone();
         scaled_shape.set_scale(shape.scale, config.scaled_shape_subdivision);
         let mut builder = ColliderBuilder::new(scaled_shape.raw.clone());

src/plugin/systems/joint.rs

@@ -2,7 +2,6 @@ use crate::dynamics::ImpulseJoint;
 use crate::dynamics::MultibodyJoint;
 use crate::dynamics::RapierImpulseJointHandle;
 use crate::dynamics::RapierMultibodyJointHandle;
-use crate::plugin::context::systemparams::get_single_context;
 use crate::plugin::context::RapierContextEntityLink;
 use crate::plugin::DefaultRapierContext;
 use crate::plugin::RapierContextAccessMut;
@@ -12,7 +11,7 @@ use bevy::prelude::*;
 pub fn init_joints(
     mut commands: Commands,
     mut context_access: RapierContextAccessMut,
-    default_context: Query<Entity, With<DefaultRapierContext>>,
+    default_context_access: Query<Entity, With<DefaultRapierContext>>,
     impulse_joints: Query<
         (Entity, Option<&RapierContextEntityLink>, &ImpulseJoint),
         Without<RapierImpulseJointHandle>,
@@ -24,19 +23,26 @@ pub fn init_joints(
     parent_query: Query<&Parent>,
 ) {
     for (entity, entity_context_link, joint) in impulse_joints.iter() {
+        // Get rapier context from RapierContextEntityLink or insert its default value.
         let context_entity = entity_context_link.map_or_else(
             || {
-                let context_entity = get_single_context(&default_context);
+                let context_entity = default_context_access.get_single().ok()?;
                 commands
                     .entity(entity)
                     .insert(RapierContextEntityLink(context_entity));
-                context_entity
+                Some(context_entity)
             },
-            |link| link.0,
+            |link| Some(link.0),
         );
-        let context = context_access
-            .context_from_entity(context_entity)
-            .into_inner();
+        let Some(context_entity) = context_entity else {
+            continue;
+        };
+
+        let Some(context) = context_access.try_context_from_entity(context_entity) else {
+            log::error!("Could not find entity {context_entity} with rapier context while initializing {entity}");
+            continue;
+        };
+        let context = context.into_inner();
         let mut target = None;
         let mut body_entity = entity;
         while target.is_none() {
@@ -63,19 +69,26 @@ pub fn init_joints(
     }
 
     for (entity, entity_context_link, joint) in multibody_joints.iter() {
+        // Get rapier context from RapierContextEntityLink or insert its default value.
         let context_entity = entity_context_link.map_or_else(
             || {
-                let context_entity = get_single_context(&default_context);
+                let context_entity = default_context_access.get_single().ok()?;
                 commands
                     .entity(entity)
                     .insert(RapierContextEntityLink(context_entity));
-                context_entity
+                Some(context_entity)
             },
-            |link| link.0,
+            |link| Some(link.0),
         );
-        let context = context_access
-            .context_from_entity(context_entity)
-            .into_inner();
+        let Some(context_entity) = context_entity else {
+            continue;
+        };
+
+        let Some(context) = context_access.try_context_from_entity(context_entity) else {
+            log::error!("Could not find entity {context_entity} with rapier context while initializing {entity}");
+            continue;
+        };
+        let context = context.into_inner();
         let target = context.entity2body.get(&entity);
 
         if let (Some(target), Some(source)) = (target, context.entity2body.get(&joint.parent)) {