Refactor to minimise std usage (#668)

bushrat011899 · web-flow · commit 9f8ce987d9fe · 2025-03-21T12:13:37.000+02:00
# Objective

- Prepare for possible `no_std` support

## Solution

- Added lints and switched to using `core` and `alloc` instead of `std`.
diff --git a/Cargo.toml b/Cargo.toml
@@ -2,5 +2,10 @@
 members = ["crates/avian2d", "crates/avian3d"]
 resolver = "2"
 
+[workspace.lints.clippy]
+alloc_instead_of_core = "warn"
+std_instead_of_alloc = "warn"
+std_instead_of_core = "warn"
+
 [profile.dev]
 opt-level = 1 # Use slightly better optimization, so examples work
diff --git a/crates/avian2d/Cargo.toml b/crates/avian2d/Cargo.toml
@@ -95,6 +95,9 @@ bytemuck = "1.19"
 criterion = { version = "0.5", features = ["html_reports"] }
 bevy_mod_debugdump = { version = "0.12" }
 
+[lints]
+workspace = true
+
 [package.metadata.docs.rs]
 # Enable features when building the docs on docs.rs
 features = ["diagnostic_ui"]
diff --git a/crates/avian2d/benches/pyramid.rs b/crates/avian2d/benches/pyramid.rs
@@ -1,4 +1,4 @@
-use std::time::Duration;
+use core::time::Duration;
 
 use avian2d::math::*;
 use avian2d::prelude::*;
diff --git a/crates/avian2d/examples/custom_collider.rs b/crates/avian2d/examples/custom_collider.rs
@@ -123,7 +123,7 @@ impl AnyCollider for CircleCollider {
 impl ComputeMassProperties2d for CircleCollider {
     fn mass(&self, density: f32) -> f32 {
         // In 2D, the Z length is assumed to be `1.0`, so volume == area.
-        let volume = std::f32::consts::PI * self.radius.powi(2) as f32;
+        let volume = core::f32::consts::PI * self.radius.powi(2) as f32;
         density * volume
     }
 
@@ -180,7 +180,7 @@ fn setup(
         .with_children(|c| {
             // Spawn obstacles along the perimeter of the rotating body, like the teeth of a cog.
             let count = 8;
-            let angle_step = std::f32::consts::TAU / count as f32;
+            let angle_step = core::f32::consts::TAU / count as f32;
             for i in 0..count {
                 let pos = Quat::from_rotation_z(i as f32 * angle_step) * Vec3::Y * center_radius;
                 c.spawn((
diff --git a/crates/avian3d/Cargo.toml b/crates/avian3d/Cargo.toml
@@ -99,6 +99,9 @@ approx = "0.5"
 criterion = { version = "0.5", features = ["html_reports"] }
 bevy_mod_debugdump = { version = "0.12" }
 
+[lints]
+workspace = true
+
 [package.metadata.docs.rs]
 # Enable features when building the docs on docs.rs
 features = ["diagnostic_ui"]
diff --git a/crates/avian3d/benches/cubes.rs b/crates/avian3d/benches/cubes.rs
@@ -1,4 +1,4 @@
-use std::time::Duration;
+use core::time::Duration;
 
 use avian3d::math::*;
 use avian3d::prelude::*;
diff --git a/crates/avian3d/examples/dynamic_character_3d/main.rs b/crates/avian3d/examples/dynamic_character_3d/main.rs
@@ -64,7 +64,7 @@ fn setup(
     // Environment (see the `collider_constructors` example for creating colliders from scenes)
     commands.spawn((
         SceneRoot(assets.load("character_controller_demo.glb#Scene0")),
-        Transform::from_rotation(Quat::from_rotation_y(-std::f32::consts::PI * 0.5)),
+        Transform::from_rotation(Quat::from_rotation_y(-core::f32::consts::PI * 0.5)),
         ColliderConstructorHierarchy::new(ColliderConstructor::ConvexHullFromMesh),
         RigidBody::Static,
     ));
diff --git a/crates/avian3d/examples/kinematic_character_3d/main.rs b/crates/avian3d/examples/kinematic_character_3d/main.rs
@@ -67,7 +67,7 @@ fn setup(
     // Environment (see the `collider_constructors` example for creating colliders from scenes)
     commands.spawn((
         SceneRoot(assets.load("character_controller_demo.glb#Scene0")),
-        Transform::from_rotation(Quat::from_rotation_y(-std::f32::consts::PI * 0.5)),
+        Transform::from_rotation(Quat::from_rotation_y(-core::f32::consts::PI * 0.5)),
         ColliderConstructorHierarchy::new(ColliderConstructor::ConvexHullFromMesh),
         RigidBody::Static,
     ));
diff --git a/crates/avian3d/examples/picking.rs b/crates/avian3d/examples/picking.rs
@@ -6,7 +6,7 @@
 //!
 //! Cameras can further filter which entities are pickable with the [`PhysicsPickingFilter`] component.
 
-use std::f32::consts::PI;
+use core::f32::consts::PI;
 
 use avian3d::{math::Vector, prelude::*};
 use bevy::{color::palettes::tailwind::*, picking::pointer::PointerInteraction, prelude::*};
diff --git a/crates/benches_common_2d/Cargo.toml b/crates/benches_common_2d/Cargo.toml
@@ -7,3 +7,6 @@ edition = "2021"
 bevy = { version = "0.15", default-features = false }
 avian2d = { path = "../avian2d", default-features = false }
 criterion = "0.5"
+
+[lints]
+workspace = true
diff --git a/crates/benches_common_3d/Cargo.toml b/crates/benches_common_3d/Cargo.toml
@@ -7,3 +7,6 @@ edition = "2021"
 bevy = { version = "0.15", default-features = false }
 avian3d = { path = "../avian3d", default-features = false }
 criterion = "0.5"
+
+[lints]
+workspace = true
diff --git a/crates/examples_common_2d/Cargo.toml b/crates/examples_common_2d/Cargo.toml
@@ -28,3 +28,6 @@ bevy = { version = "0.15", default-features = false, features = [
 avian2d = { path = "../avian2d", default-features = false, features = [
     "diagnostic_ui",
 ] }
+
+[lints]
+workspace = true
diff --git a/crates/examples_common_3d/Cargo.toml b/crates/examples_common_3d/Cargo.toml
@@ -31,3 +31,6 @@ bevy = { version = "0.15", default-features = false, features = [
 avian3d = { path = "../avian3d", default-features = false, features = [
     "diagnostic_ui",
 ] }
+
+[lints]
+workspace = true
diff --git a/src/collision/broad_phase.rs b/src/collision/broad_phase.rs
@@ -3,7 +3,7 @@
 //!
 //! See [`BroadPhasePlugin`].
 
-use std::marker::PhantomData;
+use core::marker::PhantomData;
 
 use crate::prelude::*;
 use bevy::{
diff --git a/src/collision/collider/backend.rs b/src/collision/collider/backend.rs
@@ -2,7 +2,7 @@
 //!
 //! See [`ColliderBackendPlugin`].
 
-use std::{any::type_name, marker::PhantomData};
+use core::{any::type_name, marker::PhantomData};
 
 use crate::{broad_phase::BroadPhaseSet, prelude::*, prepare::PrepareSet, sync::SyncConfig};
 #[cfg(all(feature = "bevy_scene", feature = "default-collider"))]
diff --git a/src/collision/layers.rs b/src/collision/layers.rs
@@ -1,4 +1,4 @@
-use std::ops::{BitAnd, BitAndAssign, BitOr, BitOrAssign, BitXor, BitXorAssign, Not};
+use core::ops::{BitAnd, BitAndAssign, BitOr, BitOrAssign, BitXor, BitXorAssign, Not};
 
 use bevy::prelude::*;
 
diff --git a/src/collision/mod.rs b/src/collision/mod.rs
@@ -341,7 +341,7 @@ impl Contacts {
             .max_by(|a, b| {
                 a.penetration
                     .partial_cmp(&b.penetration)
-                    .unwrap_or(std::cmp::Ordering::Equal)
+                    .unwrap_or(core::cmp::Ordering::Equal)
             })
     }
 }
@@ -435,7 +435,7 @@ impl ContactManifold {
         self.points
             .iter()
             .map(|contact| contact.normal_impulse)
-            .max_by(|a, b| a.partial_cmp(b).unwrap_or(std::cmp::Ordering::Equal))
+            .max_by(|a, b| a.partial_cmp(b).unwrap_or(core::cmp::Ordering::Equal))
             .unwrap_or(0.0)
     }
 
@@ -508,7 +508,7 @@ impl ContactManifold {
         self.points.iter().max_by(|a, b| {
             a.penetration
                 .partial_cmp(&b.penetration)
-                .unwrap_or(std::cmp::Ordering::Equal)
+                .unwrap_or(core::cmp::Ordering::Equal)
         })
     }
 }
@@ -574,8 +574,8 @@ impl SingleContact {
 
     /// Flips the contact data, swapping the points and normals.
     pub fn flip(&mut self) {
-        std::mem::swap(&mut self.local_point1, &mut self.local_point2);
-        std::mem::swap(&mut self.local_normal1, &mut self.local_normal2);
+        core::mem::swap(&mut self.local_point1, &mut self.local_point2);
+        core::mem::swap(&mut self.local_normal1, &mut self.local_normal2);
     }
 
     /// Returns a flipped copy of the contact data, swapping the points and normals.
@@ -695,8 +695,8 @@ impl ContactPoint {
     /// Flips the contact data, swapping the points and feature IDs,
     /// and negating the impulses.
     pub fn flip(&mut self) {
-        std::mem::swap(&mut self.local_point1, &mut self.local_point2);
-        std::mem::swap(&mut self.feature_id1, &mut self.feature_id2);
+        core::mem::swap(&mut self.local_point1, &mut self.local_point2);
+        core::mem::swap(&mut self.feature_id1, &mut self.feature_id2);
         self.normal_impulse = -self.normal_impulse;
         self.tangent_impulse = -self.tangent_impulse;
     }
diff --git a/src/collision/narrow_phase.rs b/src/collision/narrow_phase.rs
@@ -2,7 +2,7 @@
 //!
 //! See [`NarrowPhasePlugin`].
 
-use std::marker::PhantomData;
+use core::marker::PhantomData;
 
 use crate::{
     dynamics::solver::{
diff --git a/src/diagnostics/total.rs b/src/diagnostics/total.rs
@@ -1,4 +1,4 @@
-use std::time::Duration;
+use core::time::Duration;
 
 use bevy::{
     diagnostic::{Diagnostic, DiagnosticPath, Diagnostics, DiagnosticsStore, RegisterDiagnostic},
diff --git a/src/dynamics/rigid_body/forces.rs b/src/dynamics/rigid_body/forces.rs
@@ -3,8 +3,8 @@
 
 use crate::prelude::*;
 use bevy::prelude::*;
+use core::ops::{Deref, DerefMut};
 use derive_more::From;
-use std::ops::{Deref, DerefMut};
 
 #[cfg(feature = "2d")]
 pub(crate) type Torque = Scalar;
diff --git a/src/dynamics/rigid_body/mass_properties/system_param.rs b/src/dynamics/rigid_body/mass_properties/system_param.rs
@@ -142,7 +142,7 @@ impl MassPropertyHelper<'_, '_> {
     ///
     /// This ignores the [`NoAutoMass`], [`NoAutoAngularInertia`], and [`NoAutoCenterOfMass`] marker components.
     pub fn total_mass_properties(&self, entity: Entity) -> MassProperties {
-        std::iter::once(self.local_mass_properties(entity))
+        core::iter::once(self.local_mass_properties(entity))
             .chain(
                 self.children
                     .iter_descendants(entity)
diff --git a/src/lib.rs b/src/lib.rs
@@ -472,6 +472,8 @@ compile_error!(
     "feature \"default-collider\" requires the feature \"parry-f64\" when \"f64\" is enabled"
 );
 
+extern crate alloc;
+
 #[cfg(all(feature = "2d", feature = "parry-f32"))]
 pub extern crate parry2d as parry;
 
@@ -745,7 +747,7 @@ impl PhysicsPlugins {
     {
         PhysicsPluginsWithHooks::<H> {
             plugins: self,
-            _phantom: std::marker::PhantomData,
+            _phantom: core::marker::PhantomData,
         }
     }
 
@@ -831,7 +833,7 @@ impl PluginGroup for PhysicsPlugins {
 /// A [`PhysicsPlugins`] plugin group with [`CollisionHooks`] specified.
 pub struct PhysicsPluginsWithHooks<H: CollisionHooks> {
     plugins: PhysicsPlugins,
-    _phantom: std::marker::PhantomData<H>,
+    _phantom: core::marker::PhantomData<H>,
 }
 
 impl<H: CollisionHooks> PhysicsPluginsWithHooks<H> {
@@ -842,7 +844,7 @@ impl<H: CollisionHooks> PhysicsPluginsWithHooks<H> {
     pub fn new(schedule: impl ScheduleLabel) -> Self {
         Self {
             plugins: PhysicsPlugins::new(schedule),
-            _phantom: std::marker::PhantomData,
+            _phantom: core::marker::PhantomData,
         }
     }
 
@@ -860,7 +862,7 @@ impl<H: CollisionHooks> Default for PhysicsPluginsWithHooks<H> {
     fn default() -> Self {
         Self {
             plugins: PhysicsPlugins::default(),
-            _phantom: std::marker::PhantomData,
+            _phantom: core::marker::PhantomData,
         }
     }
 }
diff --git a/src/math/double.rs b/src/math/double.rs
@@ -4,13 +4,13 @@ use bevy_math::*;
 /// The floating point number type used by Avian.
 pub type Scalar = f64;
 /// The PI/2 constant.
-pub const FRAC_PI_2: Scalar = std::f64::consts::FRAC_PI_2;
+pub const FRAC_PI_2: Scalar = core::f64::consts::FRAC_PI_2;
 /// The PI constant.
-pub const PI: Scalar = std::f64::consts::PI;
+pub const PI: Scalar = core::f64::consts::PI;
 /// The TAU constant.
-pub const TAU: Scalar = std::f64::consts::TAU;
+pub const TAU: Scalar = core::f64::consts::TAU;
 /// 1/sqrt(2)
-pub const FRAC_1_SQRT_2: Scalar = std::f64::consts::FRAC_1_SQRT_2;
+pub const FRAC_1_SQRT_2: Scalar = core::f64::consts::FRAC_1_SQRT_2;
 
 /// The vector type used by Avian.
 #[cfg(feature = "2d")]
diff --git a/src/math/single.rs b/src/math/single.rs
@@ -4,13 +4,13 @@ use bevy_math::*;
 /// The floating point number type used by Avian.
 pub type Scalar = f32;
 /// The PI/2 constant.
-pub const FRAC_PI_2: Scalar = std::f32::consts::FRAC_PI_2;
+pub const FRAC_PI_2: Scalar = core::f32::consts::FRAC_PI_2;
 /// The PI constant.
-pub const PI: Scalar = std::f32::consts::PI;
+pub const PI: Scalar = core::f32::consts::PI;
 /// The TAU constant.
-pub const TAU: Scalar = std::f32::consts::TAU;
+pub const TAU: Scalar = core::f32::consts::TAU;
 /// 1/sqrt(2)
-pub const FRAC_1_SQRT_2: Scalar = std::f32::consts::FRAC_1_SQRT_2;
+pub const FRAC_1_SQRT_2: Scalar = core::f32::consts::FRAC_1_SQRT_2;
 
 /// The vector type used by Avian.
 #[cfg(feature = "2d")]
diff --git a/src/picking/mod.rs b/src/picking/mod.rs
@@ -28,7 +28,7 @@ use bevy::{
     prelude::*,
 };
 
-use std::time::Duration;
+use core::time::Duration;
 
 use bevy::{
     diagnostic::DiagnosticPath,
diff --git a/src/position.rs b/src/position.rs
@@ -551,7 +551,7 @@ impl From<Rotation> for Rot2 {
 }
 
 #[cfg(feature = "2d")]
-impl std::ops::Mul for Rotation {
+impl core::ops::Mul for Rotation {
     type Output = Self;
 
     fn mul(self, rhs: Self) -> Self::Output {
@@ -563,14 +563,14 @@ impl std::ops::Mul for Rotation {
 }
 
 #[cfg(feature = "2d")]
-impl std::ops::MulAssign for Rotation {
+impl core::ops::MulAssign for Rotation {
     fn mul_assign(&mut self, rhs: Self) {
         *self = *self * rhs;
     }
 }
 
 #[cfg(feature = "2d")]
-impl std::ops::Mul<Vector> for Rotation {
+impl core::ops::Mul<Vector> for Rotation {
     type Output = Vector;
 
     /// Rotates a [`Vector`] by a [`Rotation`].
diff --git a/src/schedule/mod.rs b/src/schedule/mod.rs
@@ -6,7 +6,7 @@ mod time;
 use dynamics::solver::schedule::SubstepCount;
 pub use time::*;
 
-use std::time::Duration;
+use core::time::Duration;
 
 // For doc links
 #[allow(unused_imports)]
diff --git a/src/spatial_query/diagnostics.rs b/src/spatial_query/diagnostics.rs
@@ -1,4 +1,4 @@
-use std::time::Duration;
+use core::time::Duration;
 
 use bevy::{
     diagnostic::DiagnosticPath,
diff --git a/src/spatial_query/pipeline.rs b/src/spatial_query/pipeline.rs
@@ -1,4 +1,4 @@
-use std::sync::Arc;
+use alloc::sync::Arc;
 
 use crate::prelude::*;
 use bevy::{prelude::*, utils::HashMap};
diff --git a/src/spatial_query/ray_caster.rs b/src/spatial_query/ray_caster.rs
@@ -422,14 +422,14 @@ impl RayHits {
     /// Returns an iterator over the hits in arbitrary order.
     ///
     /// If you want to get them sorted by distance, use `iter_sorted`.
-    pub fn iter(&self) -> std::slice::Iter<RayHitData> {
+    pub fn iter(&self) -> core::slice::Iter<RayHitData> {
         self.as_slice().iter()
     }
 
     /// Returns an iterator over the hits, sorted in ascending order according to the distance.
     ///
     /// Note that this creates and sorts a new vector. If you don't need the hits in order, use `iter`.
-    pub fn iter_sorted(&self) -> std::vec::IntoIter<RayHitData> {
+    pub fn iter_sorted(&self) -> alloc::vec::IntoIter<RayHitData> {
         let mut vector = self.as_slice().to_vec();
         vector.sort_by(|a, b| a.distance.partial_cmp(&b.distance).unwrap());
         vector.into_iter()
diff --git a/src/spatial_query/shape_caster.rs b/src/spatial_query/shape_caster.rs
@@ -561,7 +561,7 @@ impl ShapeHits {
     }
 
     /// Returns an iterator over the hits in the order of distance.
-    pub fn iter(&self) -> std::slice::Iter<ShapeHitData> {
+    pub fn iter(&self) -> core::slice::Iter<ShapeHitData> {
         self.as_slice().iter()
     }
 }
diff --git a/src/sync/ancestor_marker.rs b/src/sync/ancestor_marker.rs
@@ -1,6 +1,6 @@
 //! Functionality for marking ancestors of entities with marker components.
 
-use std::marker::PhantomData;
+use core::marker::PhantomData;
 
 use bevy::{
     ecs::{intern::Interned, schedule::ScheduleLabel},
diff --git a/src/tests/determinism_2d.rs b/src/tests/determinism_2d.rs
diff --git a/src/tests/mod.rs b/src/tests/mod.rs

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-use std::time::Duration;`
	`1`	`+use core::time::Duration;`
`2`	`2`
`3`	`3`	`use avian2d::math::*;`
`4`	`4`	`use avian2d::prelude::*;`