bevy_macro_utils

Shared utilities used by Bevy's proc macros. Not depended on by user code; meant to be consumed only by sibling derive crates (bevy_ecs_macros, bevy_reflect_derive, bevy_derive, etc.).

Purpose

Avoid re-implementing the same things across every derive crate:

• Locate the active bevy_* crate (so bevy_ecs::Component works whether or not the user re-exports through bevy).
• Walk syn types to find lifetimes, generics, and attribute arguments.
• Manipulate darling-style attribute parsing in a uniform way.
• Token-stream helpers and label / system-set boilerplate.

Directory layout

crates/bevy_macro_utils/src/
├── lib.rs                  # Public re-exports
├── attrs.rs                # Attribute parsing helpers
├── bevy_manifest.rs        # Find the right bevy crate path
├── label.rs                # Macro helpers for ScheduleLabel/SystemSet derives
├── shape.rs                # syn helpers for struct/enum shape introspection
├── symbol.rs               # Static identifier interning
└── …

Key abstractions

Symbol	File	Description
BevyManifest	crates/bevy_macro_utils/src/bevy_manifest.rs	Finds the path to a bevy crate from the user's Cargo.toml.
derive_label	crates/bevy_macro_utils/src/label.rs	Generates a ScheduleLabel/SystemSet/SystemLabel impl.
Symbol	crates/bevy_macro_utils/src/symbol.rs	Cached Idents.

Integration points

• Depends on: proc-macro2, quote, syn, cargo_manifest.
• Depended on by: bevy_ecs_macros, bevy_reflect_derive, bevy_derive, bevy_app macros.

Entry points for modification

• Mostly stable. Touch only when refactoring a derive macro across multiple crates.