bevy/crates/bevy_macros_compile_fail_tests/Cargo.toml

[package]
name = "bevy_macros_compile_fail_tests"
version = "0.1.0"
edition = "2021"
description = "Compile fail tests for Bevy Engine's various macros"
homepage = "https://bevyengine.org"
repository = "https://github.com/bevyengine/bevy"
license = "MIT OR Apache-2.0"
publish = false

[dependencies]
bevy_derive = { path = "../bevy_derive" }
trybuild = "1.0.71"
bevy_derive: Add `#[deref]` attribute (#8552) # Objective Bevy code tends to make heavy use of the [newtype]( https://doc.rust-lang.org/rust-by-example/generics/new_types.html) pattern, which is why we have a dedicated derive for [`Deref`](https://doc.rust-lang.org/std/ops/trait.Deref.html) and [`DerefMut`](https://doc.rust-lang.org/std/ops/trait.DerefMut.html). This derive works for any struct with a single field: ```rust #[derive(Component, Deref, DerefMut)] struct MyNewtype(usize); ``` One reason for the single-field limitation is to prevent confusion and footguns related that would arise from allowing multi-field structs: <table align="center"> <tr> <th colspan="2"> Similar structs, different derefs </th> </tr> <tr> <td> ```rust #[derive(Deref, DerefMut)] struct MyStruct { foo: usize, // <- Derefs usize bar: String, } ``` </td> <td> ```rust #[derive(Deref, DerefMut)] struct MyStruct { bar: String, // <- Derefs String foo: usize, } ``` </td> </tr> <tr> <th colspan="2"> Why `.1`? </th> </tr> <tr> <td colspan="2"> ```rust #[derive(Deref, DerefMut)] struct MyStruct(Vec<usize>, Vec<f32>); let mut foo = MyStruct(vec![123], vec![1.23]); // Why can we skip the `.0` here? foo.push(456); // But not here? foo.1.push(4.56); ``` </td> </tr> </table> However, there are certainly cases where it's useful to allow for structs with multiple fields. Such as for structs with one "real" field and one `PhantomData` to allow for generics: ```rust #[derive(Deref, DerefMut)] struct MyStruct<T>( // We want use this field for the `Deref`/`DerefMut` impls String, // But we need this field so that we can make this struct generic PhantomData<T> ); // ERROR: Deref can only be derived for structs with a single field // ERROR: DerefMut can only be derived for structs with a single field ``` Additionally, the possible confusion and footguns are mainly an issue for newer Rust/Bevy users. Those familiar with `Deref` and `DerefMut` understand what adding the derive really means and can anticipate its behavior. ## Solution Allow users to opt into multi-field `Deref`/`DerefMut` derives using a `#[deref]` attribute: ```rust #[derive(Deref, DerefMut)] struct MyStruct<T>( // Use this field for the `Deref`/`DerefMut` impls #[deref] String, // We can freely include any other field without a compile error PhantomData<T> ); ``` This prevents the footgun pointed out in the first issue described in the previous section, but it still leaves the possible confusion surrounding `.0`-vs-`.#`. However, the idea is that by making this behavior explicit with an attribute, users will be more aware of it and can adapt appropriately. --- ## Changelog - Added `#[deref]` attribute to `Deref` and `DerefMut` derives 2023-05-16 18:29:09 +00:00			`[package]`
			`name = "bevy_macros_compile_fail_tests"`
			`version = "0.1.0"`
			`edition = "2021"`
			`description = "Compile fail tests for Bevy Engine's various macros"`
			`homepage = "https://bevyengine.org"`
			`repository = "https://github.com/bevyengine/bevy"`
			`license = "MIT OR Apache-2.0"`
			`publish = false`

			`[dependencies]`
			`bevy_derive = { path = "../bevy_derive" }`
Standardize toml format with taplo (#10594) # Objective - Standardize fmt for toml files ## Solution - Add [taplo](https://taplo.tamasfe.dev/) to CI (check for fmt and diff for toml files), for context taplo is used by the most popular extension in VScode [Even Better TOML](https://marketplace.visualstudio.com/items?itemName=tamasfe.even-better-toml - Add contribution section to explain toml fmt with taplo. Now to pass CI you need to run `taplo fmt --option indent_string=" "` or if you use vscode have the `Even Better TOML` extension with 4 spaces for indent --------- Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com> 2023-11-21 01:04:14 +00:00			`trybuild = "1.0.71"`