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Merged
cart merged 5 commits into from
Jun 10, 2026
+113 −33
Merged

bsn: support field name shorthand #24526

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e08e4bc
bsn: support field name shorthand
cart Jun 4, 2026
88e6455
Merge remote-tracking branch 'origin/main' into bsn-name-shorthand
cart Jun 9, 2026
e44003b
add implicit Into for shorthand
cart Jun 10, 2026
7fca927
Add to docs
cart Jun 10, 2026
d966c29
into -> from
mockersf Jun 10, 2026
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78 changes: 47 additions & 31 deletions crates/bevy_scene/macros/src/bsn/codegen.rs
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -205,7 +205,7 @@ impl BsnEntry {
let mut assigns = Vec::new();
let target = PatchTarget {
path: &[Member::Named(Ident::new(
"value",
"__value",
proc_macro2::Span::call_site(),
))],
is_ref: true,
Expand All @@ -218,7 +218,7 @@ impl BsnEntry {
}
} else {
quote! {
let value = _scene.get_or_insert_template::<#path>(_context);
let __value = _scene.get_or_insert_template::<#path>(_context);
#(#assigns)*
}
})
Expand All @@ -227,7 +227,7 @@ impl BsnEntry {
let mut assigns = Vec::new();
let target = PatchTarget {
path: &[Member::Named(Ident::new(
"value",
"__value",
proc_macro2::Span::call_site(),
))],
is_ref: true,
Expand All @@ -240,7 +240,7 @@ impl BsnEntry {
}
} else {
quote! {
let value = _scene.get_or_insert_template::<<#path as #bevy_ecs::template::FromTemplate>::Template>(_context);
let __value = _scene.get_or_insert_template::<<#path as #bevy_ecs::template::FromTemplate>::Template>(_context);
#(#assigns)*
}
})
Expand All @@ -249,8 +249,8 @@ impl BsnEntry {
type_path,
const_ident,
} => EntryResult::CombinedSceneFunction(quote! {
let value = _scene.get_or_insert_template::<#type_path>(_context);
*value = #type_path::#const_ident;
let __value = _scene.get_or_insert_template::<#type_path>(_context);
*__value = #type_path::#const_ident;
}),
BsnEntry::TemplateConstructor(BsnConstructor {
type_path,
Expand All @@ -259,8 +259,8 @@ impl BsnEntry {
}) => EntryResult::CombinedSceneFunction({
let args = args.to_tokens(ctx);
quote! {
let value = _scene.get_or_insert_template::<#type_path>(_context);
*value = #type_path::#function #args;
let __value = _scene.get_or_insert_template::<#type_path>(_context);
*__value = #type_path::#function #args;
}
}),
BsnEntry::FromTemplateConstructor(BsnConstructor {
Expand All @@ -270,8 +270,8 @@ impl BsnEntry {
}) => EntryResult::CombinedSceneFunction({
let args = args.to_tokens(ctx);
quote! {
let value = _scene.get_or_insert_template::<<#type_path as #bevy_ecs::template::FromTemplate>::Template>(_context);
*value = <#type_path as #bevy_ecs::template::FromTemplate>::Template::#function #args;
let __value = _scene.get_or_insert_template::<<#type_path as #bevy_ecs::template::FromTemplate>::Template>(_context);
*__value = <#type_path as #bevy_ecs::template::FromTemplate>::Template::#function #args;
}
}),
BsnEntry::RelatedSceneList(BsnRelatedSceneList {
Expand Down Expand Up @@ -310,8 +310,8 @@ impl BsnScene {
// which imposes constraints like requiring the type to impl FromTemplate, and requiring
// enums to have VariantDefault.
let mut assignments = Vec::new();
let props = format_ident!("props");
let props_ref = format_ident!("props_ref");
let props = format_ident!("__props");
let props_ref = format_ident!("__props_ref");
let target = PatchTarget {
path: &[Member::Named(props_ref.clone())],
is_ref: true,
Expand All @@ -320,7 +320,7 @@ impl BsnScene {
let mut assigns = Vec::new();
let target = PatchTarget {
path: &[Member::Named(Ident::new(
"value",
"__value",
proc_macro2::Span::call_site(),
))],
is_ref: true,
Expand All @@ -329,7 +329,7 @@ impl BsnScene {
let path = &bsn_type.path;
let bevy_scene = ctx.bevy_scene;
let from_template_patch = quote! {
<#path as #bevy_scene::PatchFromTemplate>::patch(move |value, _context| {
<#path as #bevy_scene::PatchFromTemplate>::patch(move |__value, _context| {
#(#assigns)*
})
};
Expand Down Expand Up @@ -489,15 +489,15 @@ impl BsnType {
continue;
}

if field.value.is_none() {
if field.value.is_none() && !field.is_name_shorthand {
ctx.errors.push(syn::Error::new_spanned(
field_name,
format!("Field `{}` is missing a value.", field_name),
));
}

let path = if field.is_prop {
&[Member::Named(format_ident!("props"))]
&[Member::Named(format_ident!("__props"))]
} else {
target.path
};
Expand All @@ -508,6 +508,7 @@ impl BsnType {
path,
Member::Named(field_name.clone()),
field.value.as_ref(),
field.is_name_shorthand,
)?;
}
}
Expand All @@ -523,6 +524,7 @@ impl BsnType {
target.path,
Member::Unnamed(Index::from(i)),
Some(&field.value),
false,
) {
ctx.errors.push(err);
}
Expand All @@ -539,25 +541,31 @@ impl BsnType {
base_path: &[Member],
member: Member,
value: Option<&BsnValue>,
is_name_shorthand: bool,
) -> syn::Result<()> {
match value {
// NOTE: It is very important to still produce outputs for None field values. This is what
// enables field autocomplete in Rust Analyzer
None => {
if is_name_shorthand {
assignments.push(quote! {
#(#base_path.)*#member = #member.into();
});
} else {
assignments.push(quote! {
#(#base_path.)*#member;
});
}
}
// Enables field autocomplete in Rust Analyzer
Some(
BsnValue::Ident(_) | BsnValue::Expr(_) | BsnValue::Closure(_) | BsnValue::Tuple(_),
)
| None => {
// NOTE: It is very important to still produce outputs for None field values. This is what
// enables field autocomplete in Rust Analyzer
assignments.push(
value
.map(|v| {
let ident = ctx.hoisted_expressions.hoist(v);
quote! { #(#base_path.)*#member = #ident; }
})
.unwrap_or(quote! {
#(#base_path.)*#member;
}),
);
value @ (BsnValue::Ident(_)
| BsnValue::Expr(_)
| BsnValue::Closure(_)
| BsnValue::Tuple(_)),
) => {
let ident = ctx.hoisted_expressions.hoist(value);
assignments.push(quote! { #(#base_path.)*#member = #ident; });
}
Some(BsnValue::Lit(_)) => {
// value is Some
Expand Down Expand Up @@ -781,11 +789,13 @@ mod tests {
name: parse_quote!(x),
value: Some(BsnValue::Expr(quote!({}))),
is_prop: false,
is_name_shorthand: false,
},
BsnNamedField {
name: parse_quote!(x),
value: Some(BsnValue::Expr(quote!({}))),
is_prop: false,
is_name_shorthand: false,
},
]),
};
Expand Down Expand Up @@ -820,6 +830,7 @@ mod tests {
enum_variant: None,
fields: BsnFields::Named(vec![BsnNamedField {
is_prop: false,
is_name_shorthand: false,
name: parse_quote!(child_field),
value: Some(BsnValue::Type(BsnType {
path: parse_quote!(Child),
Expand All @@ -829,11 +840,13 @@ mod tests {
name: parse_quote!(x),
value: Some(BsnValue::Expr(quote!({}))),
is_prop: false,
is_name_shorthand: false,
},
BsnNamedField {
name: parse_quote!(x),
value: Some(BsnValue::Expr(quote!({}))),
is_prop: false,
is_name_shorthand: false,
},
]),
})),
Expand Down Expand Up @@ -871,6 +884,7 @@ mod tests {
enum_variant: None,
fields: BsnFields::Named(vec![BsnNamedField {
is_prop: false,
is_name_shorthand: false,
name: parse_quote!(x),
value: None,
}]),
Expand Down Expand Up @@ -908,11 +922,13 @@ mod tests {
fields: BsnFields::Named(vec![
BsnNamedField {
is_prop: false,
is_name_shorthand: false,
name: parse_quote!(x),
value: Some(BsnValue::Expr(quote!(1))),
},
BsnNamedField {
is_prop: false,
is_name_shorthand: false,
name: parse_quote!(x),
value: Some(BsnValue::Expr(quote!(2))),
},
Expand Down
3 changes: 3 additions & 0 deletions crates/bevy_scene/macros/src/bsn/parse.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -358,6 +358,7 @@ impl Parse for BsnNamedField {
false
};
let name = input.parse::<Ident>()?;
let mut is_name_shorthand = false;
let value = if input.peek(Colon) {
input.parse::<Colon>()?;

Expand All @@ -367,12 +368,14 @@ impl Parse for BsnNamedField {
Some(input.parse::<BsnValue>()?)
}
} else {
is_name_shorthand = true;
None
};
Ok(BsnNamedField {
name,
value,
is_prop,
is_name_shorthand,
})
}
}
Expand Down
2 changes: 2 additions & 0 deletions crates/bevy_scene/macros/src/bsn/types.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -91,6 +91,8 @@ pub struct BsnTuple(pub Vec<BsnValue>);
#[derive(Debug)]
pub struct BsnNamedField {
pub is_prop: bool,
/// This is a `Struct { field }` shorthand for `Struct { field: field }`
pub is_name_shorthand: bool,
pub name: Ident,
/// This is an Option to enable autocomplete when the field name is being typed
/// To improve autocomplete further we'll need to forgo a lot of the syn parsing
Expand Down
63 changes: 61 additions & 2 deletions crates/bevy_scene/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -961,6 +961,7 @@ use bevy_ecs::prelude::*;
/// | `CompA(val)`<br>`CompA(val, val)` | Tuple Component with some fields specified. Unspecified fields will be default, see [patching](self#patching) |
/// | `CompA { name: val }` | Component with some fields specified. Unspecified fields will be default, see [patching](self#patching) |
/// | `mymodule::CompA { name: val }` | Same as above, but referring to the component by module path |
/// | `CompA { name }` | Component with Rust's "field assignment shorthand". Evaluates to `CompA { name: name.into() }` |
/// | `MyEnum::Variant` | Enum Component `MyEnum` with the `Variant` variant |
/// | `template_value(component)` | Insert the component value from a variable `component` |
/// | `template_value(CompA::from_str("foo"))` | Insert the component value by immediately calling the constructor |
Expand Down Expand Up @@ -2839,11 +2840,69 @@ mod tests {
let entity = world
.spawn_scene(bsn! {
Foo {
value: vec! [ 10usize ],
value: vec! [ 10 ],
}
})
.unwrap();
assert_eq!(entity.get::<Foo>().unwrap().value, vec![10usize]);
assert_eq!(entity.get::<Foo>().unwrap().value, vec![10]);
}

#[test]
fn field_name_shorthand() {
let mut app = test_app();
let world = app.world_mut();

#[derive(Component, Default, Clone)]
struct Foo {
value: usize,
}
let value = 10usize;
let entity = world.spawn_scene(bsn! { Foo { value } }).unwrap();
assert_eq!(entity.get::<Foo>().unwrap().value, 10);

#[derive(SceneComponent, Default, Clone)]
#[scene(BarProps)]
struct Bar {
value: usize,
}

#[derive(Default)]
struct BarProps {
value: usize,
}

impl Bar {
fn scene(props: BarProps) -> impl Scene {
bsn! {Bar {
value: {props.value}
}}
}
}

let value = 10usize;
let entity = world.spawn_scene(bsn! { @Bar { @value } }).unwrap();
assert_eq!(entity.get::<Bar>().unwrap().value, 10);

#[derive(Component, Default, Clone)]
struct Baz {
value: X,
}

#[derive(Default, Clone)]
struct X;

#[derive(Default, Clone)]
struct Y;

impl From<Y> for X {
fn from(_: Y) -> Self {
X
}
}

let value = Y;
// ensure implicit Into works
let _ = world.spawn_scene(bsn! { Baz { value } }).unwrap();
}

#[test]
Expand Down
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