Toggling Lints in Code

It is possible to set lint levels on a case-by-case basis inside your code, but it requires a few more steps than setting the levels for the entire crate in Cargo.toml. First, you must register bevy as a tool. Not doing so will cause #[allow(bevy::lint_name)] and related attributes to fail to compile.

Once bevy is registered, you can toggle lints throughout your code, as long as they too are behind #[cfg_attr(bevy_lint, ...)]:

#![cfg_attr(bevy_lint, feature(register_tool), register_tool(bevy))]

// Enable the `pedantic` lint group, which is off by default.
#![cfg_attr(bevy_lint, warn(bevy::pedantic))]

// Deny panicking Bevy methods in this system when a non-panicking alternatives exist.
#[cfg_attr(bevy_lint, deny(bevy::panicking_methods))]
fn my_critical_system(world: &mut World) {
    // ...
}

There are several other ways to toggle lints, although some have varying levels of support:

MethodSupportAdditional Information
[package.metadata.bevy_lint] in Cargo.toml✅See Toggling Lints in Cargo.toml.
[workspace.metadata.bevy_lint] in Cargo.toml✅See Toggling Lints in Cargo.toml.
#[allow(...)] and related✅Must be behind #[cfg_attr(bevy_lint, ...)] on stable Rust.
[lints.bevy] in Cargo.toml⚠️Nightly only because #[register_tool(bevy)] must always be enabled. Prints a warning each time cargo is run.
[workspace.lints.bevy] in Cargo.toml⚠️Same as [lints.bevy].
RUSTFLAGS="-A bevy::lint"❌RUSTFLAGS applies to dependencies, but they do not have #[register_tool(bevy)].