# Objective - Contributes to #15460 ## Solution - Added the following features: - `std` (default) - `async_executor` (default) - `edge_executor` - `critical-section` - `portable-atomic` - Gated `tracing` in `bevy_utils` to allow compilation on certain platforms - Switched from `tracing` to `log` for simple message logging within `bevy_ecs`. Note that `tracing` supports capturing from `log` so this should be an uncontroversial change. - Fixed imports and added feature gates as required - Made `bevy_tasks` optional within `bevy_ecs`. Turns out it's only needed for parallel operations which are already gated behind `multi_threaded` anyway. ## Testing - Added to `compile-check-no-std` CI command - `cargo check -p bevy_ecs --no-default-features --features edge_executor,critical-section,portable-atomic --target thumbv6m-none-eabi` - `cargo check -p bevy_ecs --no-default-features --features edge_executor,critical-section` - `cargo check -p bevy_ecs --no-default-features` ## Draft Release Notes Bevy's core ECS now supports `no_std` platforms. In prior versions of Bevy, it was not possible to work with embedded or niche platforms due to our reliance on the standard library, `std`. This has blocked a number of novel use-cases for Bevy, such as an embedded database for IoT devices, or for creating games on retro consoles. With this release, `bevy_ecs` no longer requires `std`. To use Bevy on a `no_std` platform, you must disable default features and enable the new `edge_executor` and `critical-section` features. You may also need to enable `portable-atomic` and `critical-section` if your platform does not natively support all atomic types and operations used by Bevy. ```toml [dependencies] bevy_ecs = { version = "0.16", default-features = false, features = [ # Required for platforms with incomplete atomics (e.g., Raspberry Pi Pico) "portable-atomic", "critical-section", # Optional "bevy_reflect", "serialize", "bevy_debug_stepping", "edge_executor" ] } ``` Currently, this has been tested on bare-metal x86 and the Raspberry Pi Pico. If you have trouble using `bevy_ecs` on a particular platform, please reach out either through a GitHub issue or in the `no_std` working group on the Bevy Discord server. Keep an eye out for future `no_std` updates as we continue to improve the parity between `std` and `no_std`. We look forward to seeing what kinds of applications are now possible with Bevy! ## Notes - Creating PR in draft to ensure CI is passing before requesting reviews. - This implementation has no support for multithreading in `no_std`, especially due to `NonSend` being unsound if allowed in multithreading. The reason is we cannot check the `ThreadId` in `no_std`, so we have no mechanism to at-runtime determine if access is sound. --------- Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com> Co-authored-by: Vic <59878206+Victoronz@users.noreply.github.com>
10 lines
329 B
Rust
10 lines
329 B
Rust
//! Contains error and result helpers for use in fallible systems.
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use alloc::boxed::Box;
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/// A dynamic error type for use in fallible systems.
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pub type Error = Box<dyn core::error::Error + Send + Sync + 'static>;
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/// A result type for use in fallible systems.
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pub type Result<T = (), E = Error> = core::result::Result<T, E>;
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