# Objective
- `bevy_state_macros` is a new crate added in the 0.14
- it already exists outside of the bevy org:
https://crates.io/crates/bevy_state_macros
## Solution
- Rename the crate
# Objective
Prerequisite to #13579.
Combine separate `Substates` transition systems to centralize transition
logic and exert more control over it.
## Solution
Originally the transition happened in 2 stages:
- `apply_state_transition` in `ManualTransitions` handled `NextState`,
- closure system in `DependentTransitions` handled parent-related
changes, insertion and deletion of the substate.
Now:
- Both transitions are processed in a single closure system during
`DependentTransitions`.
- Since `Substates` no longer use `ManualTransitions`, it's been renamed
to `RootTransitions`. Only root states use it.
- When `Substates` state comes into existence, it will try to initialize
from `NextState` and fallback to `should_exist` result.
- Remove `apply_state_transition` from public API.
Consequentially, removed the possibility of multiple
`StateTransitionEvent`s when both transition systems fire in a single
frame.
## Changelog
- Renamed `ManualTransitions` to `RootTransitions`.
- `Substates` will initialize their value with `NextState` if available
and fallback to `should_exist` result.
## Migration Guide
- `apply_state_transition` is no longer publicly available, run the
`StateTransition` schedule instead.
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Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Extracts the state mechanisms into a new crate called "bevy_state".
This comes with a few goals:
- state wasn't really an inherent machinery of the ecs system, and so
keeping it within bevy_ecs felt forced
- by mixing it in with bevy_ecs, the maintainability of our more robust
state system was significantly compromised
moving state into a new crate makes it easier to encapsulate as it's own
feature, and easier to read and understand since it's no longer a
single, massive file.
## Solution
move the state-related elements from bevy_ecs to a new crate
## Testing
- Did you test these changes? If so, how? all the automated tests
migrated and passed, ran the pre-existing examples without changes to
validate.
---
## Migration Guide
Since bevy_state is now gated behind the `bevy_state` feature, projects
that use state but don't use the `default-features` will need to add
that feature flag.
Since it is no longer part of bevy_ecs, projects that use bevy_ecs
directly will need to manually pull in `bevy_state`, trigger the
StateTransition schedule, and handle any of the elements that bevy_app
currently sets up.
---------
Co-authored-by: Kristoffer Søholm <k.soeholm@gmail.com>
