forestia/bevy
2
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Allow SystemParams with private fields (#7056)

Browse Source 
# Objective

- Fix #4200

Currently, `#[derive(SystemParam)]` publicly exposes each field type, which makes it impossible to encapsulate private fields.

## Solution

Previously, the fields were leaked because they were used as an input generic type to the macro-generated `SystemParam::State` struct. That type has been changed to store its state in a field with a specific type, instead of a generic type.

---

## Changelog

- Fixed a bug that caused `#[derive(SystemParam)]` to leak the types of private fields.
This commit is contained in:
JoJoJet 2023-01-04 23:25:36 +00:00
parent 9ff111e24c
commit 8ca3d0462c
2 changed files with 17 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
crates/bevy_ecs/macros/src/lib.rs
View File

@ -411,7 +411,7 @@ pub fn derive_system_param(input: TokenStream) -> TokenStream {
} }
} }
let (_impl_generics, ty_generics, where_clause) = generics.split_for_impl(); let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
let lifetimeless_generics: Vec<_> = generics let lifetimeless_generics: Vec<_> = generics
.params .params
@ -441,12 +441,6 @@ pub fn derive_system_param(input: TokenStream) -> TokenStream {
} }
} }
let mut punctuated_type_generic_idents = Punctuated::<_, Token![,]>::new();
punctuated_type_generic_idents.extend(lifetimeless_generics.iter().filter_map(|g| match g {
GenericParam::Type(g) => Some(&g.ident),
_ => None,
}));
let mut punctuated_generic_idents = Punctuated::<_, Token![,]>::new(); let mut punctuated_generic_idents = Punctuated::<_, Token![,]>::new();
punctuated_generic_idents.extend(lifetimeless_generics.iter().map(|g| match g { punctuated_generic_idents.extend(lifetimeless_generics.iter().map(|g| match g {
GenericParam::Type(g) => &g.ident, GenericParam::Type(g) => &g.ident,
@ -485,24 +479,21 @@ pub fn derive_system_param(input: TokenStream) -> TokenStream {
// The struct can still be accessed via SystemParam::State, e.g. EventReaderState can be accessed via // The struct can still be accessed via SystemParam::State, e.g. EventReaderState can be accessed via
// <EventReader<'static, 'static, T> as SystemParam>::State // <EventReader<'static, 'static, T> as SystemParam>::State
const _: () = { const _: () = {
impl<'w, 's, #punctuated_generics> #path::system::SystemParam for #struct_name #ty_generics #where_clause { impl #impl_generics #path::system::SystemParam for #struct_name #ty_generics #where_clause {
type State = State<'w, 's, #punctuated_generic_idents>; type State = FetchState<'static, 'static, #punctuated_generic_idents>;
} }
#[doc(hidden)] #[doc(hidden)]
type State<'w, 's, #punctuated_generics_no_bounds> = FetchState< #state_struct_visibility struct FetchState <'w, 's, #(#lifetimeless_generics,)*> {
(#(<#tuple_types as #path::system::SystemParam>::State,)*), state: (#(<#tuple_types as #path::system::SystemParam>::State,)*),
#punctuated_generic_idents marker: std::marker::PhantomData<(
>; <#path::prelude::Query<'w, 's, ()> as #path::system::SystemParam>::State,
#(fn() -> #ignored_field_types,)*
#[doc(hidden)] )>,
#state_struct_visibility struct FetchState <TSystemParamState, #punctuated_generics> {
state: TSystemParamState,
marker: std::marker::PhantomData<fn()->(#punctuated_type_generic_idents)>
} }
unsafe impl<'__w, '__s, #punctuated_generics> #path::system::SystemParamState for unsafe impl<#punctuated_generics> #path::system::SystemParamState for
State<'__w, '__s, #punctuated_generic_idents> FetchState<'static, 'static, #punctuated_generic_idents>
#where_clause { #where_clause {
type Item<'w, 's> = #struct_name #ty_generics; type Item<'w, 's> = #struct_name #ty_generics;

6
crates/bevy_ecs/src/system/system_param.rs
View File

@ -1809,4 +1809,10 @@ mod tests {
Res<'w, R>, Res<'w, R>,
Local<'s, L>, Local<'s, L>,
); );
#[derive(Resource)]
struct PrivateResource;
#[derive(SystemParam)]
pub struct EncapsulatedParam<'w>(Res<'w, PrivateResource>);
} }