Clean up some low level dependencies (#12858)

# Objective
Minimize the number of dependencies low in the tree.

## Solution

* Remove the dependency on rustc-hash in bevy_ecs (not used) and
bevy_macro_utils (only used in one spot).
* Deduplicate the dependency on `sha1_smol` with the existing blake3
dependency already being used for bevy_asset.
 * Remove the unused `ron` dependency on `bevy_app`
* Make the `serde` dependency for `bevy_ecs` optional. It's only used
for serializing Entity.
* Change the `wgpu` dependency to `wgpu-types`, and make it optional for
`bevy_color`.
 * Remove the unused `thread-local` dependency on `bevy_render`.
* Make multiple dependencies for `bevy_tasks` optional and enabled only
when running with the `multi-threaded` feature. Preferably they'd be
disabled all the time on wasm, but I couldn't find a clean way to do
this.

---

## Changelog
TODO 

## Migration Guide
TODO

crates/bevy_animation/Cargo.toml

@@ -33,7 +33,7 @@ fixedbitset = "0.5"
 petgraph = { version = "0.6", features = ["serde-1"] }
 ron = "0.8"
 serde = "1"
-sha1_smol = { version = "1.0" }
+blake3 = { version = "1.0" }
 thiserror = "1"
 thread_local = "1"
 uuid = { version = "1.7", features = ["v4"] }

crates/bevy_animation/src/lib.rs

@@ -39,7 +39,6 @@ use graph::{AnimationGraph, AnimationNodeIndex};
 use petgraph::graph::NodeIndex;
 use petgraph::Direction;
 use prelude::{AnimationGraphAssetLoader, AnimationTransitions};
-use sha1_smol::Sha1;
 use thread_local::ThreadLocal;
 use uuid::Uuid;
 
@@ -1160,10 +1159,12 @@ impl AnimationTargetId {
     /// Typically, this will be the path from the animation root to the
     /// animation target (e.g. bone) that is to be animated.
     pub fn from_names<'a>(names: impl Iterator<Item = &'a Name>) -> Self {
-        let mut sha1 = Sha1::new();
+        let mut blake3 = blake3::Hasher::new();
-        sha1.update(ANIMATION_TARGET_NAMESPACE.as_bytes());
+        blake3.update(ANIMATION_TARGET_NAMESPACE.as_bytes());
-        names.for_each(|name| sha1.update(name.as_bytes()));
+        for name in names {
-        let hash = sha1.digest().bytes()[0..16].try_into().unwrap();
+            blake3.update(name.as_bytes());
+        }
+        let hash = blake3.finalize().as_bytes()[0..16].try_into().unwrap();
         Self(*uuid::Builder::from_sha1_bytes(hash).as_uuid())
     }
 

crates/bevy_app/Cargo.toml

@@ -13,6 +13,7 @@ trace = []
 bevy_debug_stepping = []
 default = ["bevy_reflect"]
 bevy_reflect = ["dep:bevy_reflect", "bevy_ecs/bevy_reflect"]
+serialize = ["bevy_ecs/serde"]
 
 [dependencies]
 # bevy
@@ -24,7 +25,6 @@ bevy_tasks = { path = "../bevy_tasks", version = "0.14.0-dev" }
 
 # other
 serde = { version = "1.0", features = ["derive"], optional = true }
-ron = { version = "0.8.0", optional = true }
 downcast-rs = "1.2.0"
 thiserror = "1.0"
 

crates/bevy_color/Cargo.toml

@@ -16,7 +16,7 @@ bevy_reflect = { path = "../bevy_reflect", version = "0.14.0-dev", features = [
 bytemuck = "1"
 serde = { version = "1.0", features = ["derive"], optional = true }
 thiserror = "1.0"
-wgpu = { version = "0.19.3", default-features = false }
+wgpu-types = { version = "0.19", default-features = false, optional = true }
 encase = { version = "0.7", default-features = false }
 
 [features]

crates/bevy_color/src/linear_rgba.rs

@@ -293,9 +293,10 @@ impl From<LinearRgba> for Vec4 {
     }
 }
 
-impl From<LinearRgba> for wgpu::Color {
+#[cfg(feature = "wgpu-types")]
+impl From<LinearRgba> for wgpu_types::Color {
     fn from(color: LinearRgba) -> Self {
-        wgpu::Color {
+        wgpu_types::Color {
             r: color.red as f64,
             g: color.green as f64,
             b: color.blue as f64,

crates/bevy_ecs/Cargo.toml

@@ -21,13 +21,12 @@ bevy_reflect = { path = "../bevy_reflect", version = "0.14.0-dev", optional = tr
 bevy_tasks = { path = "../bevy_tasks", version = "0.14.0-dev" }
 bevy_utils = { path = "../bevy_utils", version = "0.14.0-dev" }
 bevy_ecs_macros = { path = "macros", version = "0.14.0-dev" }
-petgraph = "0.6"
 
+petgraph = "0.6"
 bitflags = "2.3"
 concurrent-queue = "2.4.0"
 fixedbitset = "0.5"
-rustc-hash = "1.1"
+serde = { version = "1", optional = true, default-features = false }
-serde = "1"
 thiserror = "1.0"
 nonmax = "0.5"
 arrayvec = { version = "0.7.4", optional = true }

crates/bevy_ecs/src/entity/mod.rs

@@ -37,7 +37,9 @@
 //! [`EntityWorldMut::remove`]: crate::world::EntityWorldMut::remove
 mod map_entities;
 #[cfg(feature = "bevy_reflect")]
-use bevy_reflect::{Reflect, ReflectDeserialize, ReflectSerialize};
+use bevy_reflect::Reflect;
+#[cfg(all(feature = "bevy_reflect", feature = "serde"))]
+use bevy_reflect::{ReflectDeserialize, ReflectSerialize};
 pub use map_entities::*;
 
 mod hash;
@@ -55,6 +57,7 @@ use crate::{
     },
     storage::{SparseSetIndex, TableId, TableRow},
 };
+#[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 use std::{fmt, hash::Hash, mem, num::NonZeroU32, sync::atomic::Ordering};
 
@@ -141,9 +144,10 @@ type IdCursor = isize;
 /// [SemVer]: https://semver.org/
 #[derive(Clone, Copy, Debug)]
 #[cfg_attr(feature = "bevy_reflect", derive(Reflect))]
+#[cfg_attr(feature = "bevy_reflect", reflect_value(Hash, PartialEq))]
 #[cfg_attr(
-    feature = "bevy_reflect",
+    all(feature = "bevy_reflect", feature = "serde"),
-    reflect_value(Hash, PartialEq, Serialize, Deserialize)
+    reflect_value(Serialize, Deserialize)
 )]
 // Alignment repr necessary to allow LLVM to better output
 // optimised codegen for `to_bits`, `PartialEq` and `Ord`.
@@ -364,6 +368,7 @@ impl From<Entity> for Identifier {
     }
 }
 
+#[cfg(feature = "serde")]
 impl Serialize for Entity {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -373,6 +378,7 @@ impl Serialize for Entity {
     }
 }
 
+#[cfg(feature = "serde")]
 impl<'de> Deserialize<'de> for Entity {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where

crates/bevy_macro_utils/Cargo.toml

@@ -14,7 +14,6 @@ toml_edit = { version = "0.22.7", default-features = false, features = [
 ] }
 syn = "2.0"
 quote = "1.0"
-rustc-hash = "1.0"
 proc-macro2 = "1.0"
 
 [lints]

crates/bevy_macro_utils/src/label.rs

@@ -1,6 +1,6 @@
 use proc_macro::{TokenStream, TokenTree};
 use quote::{quote, quote_spanned};
-use rustc_hash::FxHashSet;
+use std::collections::HashSet;
 use syn::{spanned::Spanned, Ident};
 
 /// Finds an identifier that will not conflict with the specified set of tokens.
@@ -15,7 +15,7 @@ pub fn ensure_no_collision(value: Ident, haystack: TokenStream) -> Ident {
         // List of token streams that will be visited in future loop iterations.
         let mut unvisited = vec![haystack];
         // Identifiers we have found while searching tokens.
-        let mut found = FxHashSet::default();
+        let mut found = HashSet::new();
         while let Some(tokens) = unvisited.pop() {
             for t in tokens {
                 match t {

crates/bevy_pbr/Cargo.toml

@@ -16,7 +16,7 @@ shader_format_glsl = ["bevy_render/shader_format_glsl"]
 trace = ["bevy_render/trace"]
 ios_simulator = ["bevy_render/ios_simulator"]
 # Enables the meshlet renderer for dense high-poly scenes (experimental)
-meshlet = []
+meshlet = ["dep:range-alloc", "dep:bincode"]
 # Enables processing meshes into meshlet meshes
 meshlet_processor = ["dep:meshopt", "dep:thiserror"]
 
@@ -47,8 +47,8 @@ bytemuck = { version = "1", features = ["derive", "must_cast"] }
 radsort = "0.1"
 smallvec = "1.6"
 serde = { version = "1", features = ["derive", "rc"] }
-bincode = "1"
+bincode = { version = "1", optional = true }
-range-alloc = "0.1"
+range-alloc = { version = "0.1", optional = true }
 nonmax = "0.5"
 static_assertions = "1"
 

crates/bevy_render/Cargo.toml

@@ -41,6 +41,7 @@ bevy_app = { path = "../bevy_app", version = "0.14.0-dev" }
 bevy_asset = { path = "../bevy_asset", version = "0.14.0-dev" }
 bevy_color = { path = "../bevy_color", version = "0.14.0-dev", features = [
   "serialize",
+  "wgpu-types",
 ] }
 bevy_core = { path = "../bevy_core", version = "0.14.0-dev" }
 bevy_derive = { path = "../bevy_derive", version = "0.14.0-dev" }
@@ -82,7 +83,6 @@ serde = { version = "1", features = ["derive"] }
 bitflags = { version = "2.3", features = ["serde"] }
 bytemuck = { version = "1.5", features = ["derive", "must_cast"] }
 downcast-rs = "1.2.0"
-thread_local = "1.1"
 thiserror = "1.0"
 futures-lite = "2.0.1"
 hexasphere = "10.0"

crates/bevy_scene/Cargo.toml

@@ -10,7 +10,7 @@ keywords = ["bevy"]
 
 [features]
 default = ["serialize"]
-serialize = ["dep:serde", "uuid/serde"]
+serialize = ["dep:serde", "uuid/serde", "bevy_app/serialize"]
 
 [dependencies]
 # bevy

crates/bevy_tasks/Cargo.toml

@@ -9,15 +9,15 @@ license = "MIT OR Apache-2.0"
 keywords = ["bevy"]
 
 [features]
-multi-threaded = []
+multi-threaded = ["dep:async-channel", "dep:async-task", "dep:concurrent-queue"]
 
 [dependencies]
 futures-lite = "2.0.1"
 async-executor = "1.7.2"
-async-channel = "2.2.0"
+async-channel = { version = "2.2.0", optional = true }
 async-io = { version = "2.0.0", optional = true }
-async-task = "4.2.0"
+async-task = { version = "4.2.0", optional = true }
-concurrent-queue = "2.0.0"
+concurrent-queue = { version = "2.0.0", optional = true }
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 wasm-bindgen-futures = "0.4"