From d9702d35f18b60e73828b6edf0ddc05b88267229 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=B9=E5=90=89=E5=B3=B0?= <jifeng.yin@gmail.com>
Date: Thu, 3 Aug 2023 15:47:09 +0800
Subject: [PATCH] opt-out `multi-threaded` feature flag (#9269)

# Objective

Fixes #9113

## Solution

disable `multi-threaded` default feature

## Migration Guide
The `multi-threaded` feature in `bevy_ecs` and `bevy_tasks` is no longer
enabled by default. However, this remains a default feature for the
umbrella `bevy` crate. If you depend on `bevy_ecs` or `bevy_tasks`
directly, you should consider enabling this to allow systems to run in
parallel.
---
 crates/bevy_ecs/Cargo.toml                         | 2 +-
 crates/bevy_tasks/Cargo.toml                       | 1 -
 crates/bevy_tasks/src/lib.rs                       | 4 ++--
 crates/bevy_tasks/src/single_threaded_task_pool.rs | 1 -
 4 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/crates/bevy_ecs/Cargo.toml b/crates/bevy_ecs/Cargo.toml
index dc13ba8ee0..980174d833 100644
--- a/crates/bevy_ecs/Cargo.toml
+++ b/crates/bevy_ecs/Cargo.toml
@@ -12,7 +12,7 @@ categories = ["game-engines", "data-structures"]
 [features]
 trace = []
 multi-threaded = ["bevy_tasks/multi-threaded"]
-default = ["bevy_reflect", "multi-threaded"]
+default = ["bevy_reflect"]
 
 [dependencies]
 bevy_ptr = { path = "../bevy_ptr", version = "0.12.0-dev" }
diff --git a/crates/bevy_tasks/Cargo.toml b/crates/bevy_tasks/Cargo.toml
index bcedb8b944..d7d2f8fb6c 100644
--- a/crates/bevy_tasks/Cargo.toml
+++ b/crates/bevy_tasks/Cargo.toml
@@ -10,7 +10,6 @@ keywords = ["bevy"]
 
 [features]
 multi-threaded = []
-default = ["multi-threaded"]
 
 [dependencies]
 futures-lite = "1.4.0"
diff --git a/crates/bevy_tasks/src/lib.rs b/crates/bevy_tasks/src/lib.rs
index ffdce2d63c..b97d2e9df4 100644
--- a/crates/bevy_tasks/src/lib.rs
+++ b/crates/bevy_tasks/src/lib.rs
@@ -23,9 +23,9 @@ mod usages;
 pub use usages::tick_global_task_pools_on_main_thread;
 pub use usages::{AsyncComputeTaskPool, ComputeTaskPool, IoTaskPool};
 
-#[cfg(not(target_arch = "wasm32"))]
+#[cfg(all(not(target_arch = "wasm32"), feature = "multi-threaded"))]
 mod thread_executor;
-#[cfg(not(target_arch = "wasm32"))]
+#[cfg(all(not(target_arch = "wasm32"), feature = "multi-threaded"))]
 pub use thread_executor::{ThreadExecutor, ThreadExecutorTicker};
 
 mod iter;
diff --git a/crates/bevy_tasks/src/single_threaded_task_pool.rs b/crates/bevy_tasks/src/single_threaded_task_pool.rs
index 92e2928124..2e47468b8e 100644
--- a/crates/bevy_tasks/src/single_threaded_task_pool.rs
+++ b/crates/bevy_tasks/src/single_threaded_task_pool.rs
@@ -1,4 +1,3 @@
-#[cfg(target_arch = "wasm32")]
 use std::sync::Arc;
 use std::{cell::RefCell, future::Future, marker::PhantomData, mem, rc::Rc};