'&World conflicts with a previous mutable system parameter. Allowing this would break Rust's | Bevy | Page 1

ashen olive Aug 21, 2023, 2:57 PM

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ruby cobalt Aug 21, 2023, 3:05 PM

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The problem is that stuff like ResMut, &mut MyComponent, etc. require mutable access to the world. So it would be unsound and break Rust’s borrow rules to have both a mutable access and immutable one to the world

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There are a few possible solutions I can think of:

Try and turn the &World param into exactly the params you need
Use ParamSet to safely access &World (https://docs.rs/bevy/latest/bevy/ecs/prelude/struct.ParamSet.html)
Make this system exclusive with &mut World

ParamSet in bevy::ecs::prelude - Rust

A collection of potentially conflicting SystemParams allowed by disjoint access.

faint kraken Aug 21, 2023, 3:12 PM

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And once you have &mut World, resource_scope can be really handy

#'&World conflicts with a previous mutable system parameter. Allowing this would break Rust's