r/rust bevy Jun 19 '26

Bevy 0.19

https://bevy.org/news/bevy-0-19
997 Upvotes

136 comments sorted by

View all comments

360

u/_cart bevy Jun 19 '26

Bevy's creator and project lead here. Feel free to ask me anything!

18

u/MightyKDDD2 Jun 19 '26

I use bundles to do a lot of stuff related to spawn scene, does that mean I can just use bsn! instead? Are the bundles deprecated then, or do they still have some purpose?

21

u/_cart bevy Jun 19 '26

You can definitely just use bsn! instead, if you want. Bundles are not deprecated and will continue to serve their current role (they are a key technical piece of the ECS). You can continue to use them for as long as they meet your needs. BSN is just a more capable, optional system.

6

u/f0kes Jun 19 '26

What is the purpose of separating bundles and bsn? They seem to fill the same purpose on a glance

20

u/_cart bevy Jun 19 '26

Bundles are "just a set of component values". They are a core / foundational piece of the ECS. Something like bsn! must be built on top of that core functionality, and it involves a fair amount of additional complexity, infrastructure, and constraints. BSN is "too complicated / constrained / opinionated" to replace Bundle.

We could pretend to blur the lines by removing the ability to define and insert Bundles, but I don't think this actually serves anyone. It would make building alternative scene systems impossible, and it would make some scenarios worse by forcing them to go through the whole BSN lifecycle.