120b733ab5
# Objective We want to deny the following lints: * `clippy::allow_attributes` - Because there's no reason to `#[allow(...)]` an attribute if it wouldn't lint against anything; you should always use `#[expect(...)]` * `clippy::allow_attributes_without_reason` - Because documenting the reason for allowing/expecting a lint is always good ## Solution Set the `clippy::allow_attributes` and `clippy::allow_attributes_without_reason` lints to `deny`, and bring `bevy_reflect` in line with the new restrictions. No code changes have been made - except if a lint that was previously `allow(...)`'d could be removed via small code changes. For example, `unused_variables` can be handled by adding a `_` to the beginning of a field's name. ## Testing I ran `cargo clippy`, and received no errors.
129 lines
5.2 KiB
Rust
129 lines
5.2 KiB
Rust
use crate::{FromType, PartialReflect, Reflect};
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use alloc::boxed::Box;
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/// A trait that enables types to be dynamically constructed from reflected data.
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///
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/// It's recommended to use the [derive macro] rather than manually implementing this trait.
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///
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/// `FromReflect` allows dynamic proxy types, like [`DynamicStruct`], to be used to generate
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/// their concrete counterparts.
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/// It can also be used to partially or fully clone a type (depending on whether it has
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/// ignored fields or not).
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///
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/// In some cases, this trait may even be required.
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/// Deriving [`Reflect`] on an enum requires all its fields to implement `FromReflect`.
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/// Additionally, some complex types like `Vec<T>` require that their element types
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/// implement this trait.
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/// The reason for such requirements is that some operations require new data to be constructed,
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/// such as swapping to a new variant or pushing data to a homogeneous list.
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///
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/// See the [crate-level documentation] to see how this trait can be used.
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///
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/// [derive macro]: bevy_reflect_derive::FromReflect
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/// [`DynamicStruct`]: crate::DynamicStruct
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/// [crate-level documentation]: crate
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#[diagnostic::on_unimplemented(
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message = "`{Self}` does not implement `FromReflect` so cannot be created through reflection",
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note = "consider annotating `{Self}` with `#[derive(Reflect)]`"
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)]
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pub trait FromReflect: Reflect + Sized {
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/// Constructs a concrete instance of `Self` from a reflected value.
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fn from_reflect(reflect: &dyn PartialReflect) -> Option<Self>;
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/// Attempts to downcast the given value to `Self` using,
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/// constructing the value using [`from_reflect`] if that fails.
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///
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/// This method is more efficient than using [`from_reflect`] for cases where
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/// the given value is likely a boxed instance of `Self` (i.e. `Box<Self>`)
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/// rather than a boxed dynamic type (e.g. [`DynamicStruct`], [`DynamicList`], etc.).
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///
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/// [`from_reflect`]: Self::from_reflect
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/// [`DynamicStruct`]: crate::DynamicStruct
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/// [`DynamicList`]: crate::DynamicList
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fn take_from_reflect(
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reflect: Box<dyn PartialReflect>,
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) -> Result<Self, Box<dyn PartialReflect>> {
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match reflect.try_take::<Self>() {
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Ok(value) => Ok(value),
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Err(value) => match Self::from_reflect(value.as_ref()) {
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None => Err(value),
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Some(value) => Ok(value),
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},
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}
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}
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}
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/// Type data that represents the [`FromReflect`] trait and allows it to be used dynamically.
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///
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/// `FromReflect` allows dynamic types (e.g. [`DynamicStruct`], [`DynamicEnum`], etc.) to be converted
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/// to their full, concrete types. This is most important when it comes to deserialization where it isn't
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/// guaranteed that every field exists when trying to construct the final output.
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///
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/// However, to do this, you normally need to specify the exact concrete type:
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///
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/// ```
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/// # use bevy_reflect::{DynamicTupleStruct, FromReflect, Reflect};
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/// #[derive(Reflect, PartialEq, Eq, Debug)]
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/// struct Foo(#[reflect(default = "default_value")] usize);
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///
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/// fn default_value() -> usize { 123 }
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///
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/// let reflected = DynamicTupleStruct::default();
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///
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/// let concrete: Foo = <Foo as FromReflect>::from_reflect(&reflected).unwrap();
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///
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/// assert_eq!(Foo(123), concrete);
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/// ```
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///
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/// In a dynamic context where the type might not be known at compile-time, this is nearly impossible to do.
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/// That is why this type data struct exists— it allows us to construct the full type without knowing
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/// what the actual type is.
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///
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/// # Example
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///
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/// ```
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/// # use bevy_reflect::{DynamicTupleStruct, Reflect, ReflectFromReflect, Typed, TypeRegistry, TypePath};
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/// # #[derive(Reflect, PartialEq, Eq, Debug)]
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/// # struct Foo(#[reflect(default = "default_value")] usize);
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/// # fn default_value() -> usize { 123 }
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/// # let mut registry = TypeRegistry::new();
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/// # registry.register::<Foo>();
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///
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/// let mut reflected = DynamicTupleStruct::default();
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/// reflected.set_represented_type(Some(<Foo as Typed>::type_info()));
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///
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/// let registration = registry.get_with_type_path(<Foo as TypePath>::type_path()).unwrap();
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/// let rfr = registration.data::<ReflectFromReflect>().unwrap();
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///
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/// let concrete: Box<dyn Reflect> = rfr.from_reflect(&reflected).unwrap();
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///
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/// assert_eq!(Foo(123), concrete.take::<Foo>().unwrap());
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/// ```
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///
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/// [`DynamicStruct`]: crate::DynamicStruct
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/// [`DynamicEnum`]: crate::DynamicEnum
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#[derive(Clone)]
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pub struct ReflectFromReflect {
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from_reflect: fn(&dyn PartialReflect) -> Option<Box<dyn Reflect>>,
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}
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impl ReflectFromReflect {
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/// Perform a [`FromReflect::from_reflect`] conversion on the given reflection object.
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///
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/// This will convert the object to a concrete type if it wasn't already, and return
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/// the value as `Box<dyn Reflect>`.
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pub fn from_reflect(&self, reflect_value: &dyn PartialReflect) -> Option<Box<dyn Reflect>> {
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(self.from_reflect)(reflect_value)
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}
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}
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impl<T: FromReflect> FromType<T> for ReflectFromReflect {
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fn from_type() -> Self {
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Self {
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from_reflect: |reflect_value| {
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T::from_reflect(reflect_value).map(|value| Box::new(value) as Box<dyn Reflect>)
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},
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}
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}
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}
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