hot_patching.md

---

title: Hot Patching Systems in a Running App
authors: ["@mockersf"]
pull_requests: [19309]

---

Bevy now supports hot patching systems through subsecond from the Dixous project.

Enabled with the feature hotpatching, every system can now be modified during execution, and the change directly visible in your game.

Run BEVY_ASSET_ROOT="." dx serve --hot-patch --example hotpatching_systems --features hotpatching to test it.

dx is the Dioxus CLI, to install it run cargo install [email protected] TODO: use the fixed version that will match the version of subsecond dependency used in Bevy at release time

Known limitations:

• Only works on the binary crate (todo: plan to support it in Dioxus)

• Not supported in Wasm (todo: supported in Dioxus but not yet implemented in Bevy)

• No system signature change support (todo: add that in Bevy)

• May be sensitive to rust/linker configuration (todo: better support in Dioxus)