# Objective
Title.
---------
Co-authored-by: François <mockersf@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: James Liu <contact@jamessliu.com>
# Objective
- Fixes#7659
## Solution
The idea of anonymous system sets or "implicit hidden organizational
sets" was briefly mentioned by @cart here:
https://github.com/bevyengine/bevy/pull/7634#issuecomment-1428619449.
- `Schedule::add_systems` creates an implicit, anonymous system set of
all systems in `SystemConfigs`.
- All dependencies and conditions from the `SystemConfigs` are now
applied to the implicit system set, instead of being applied to each
individual system. This should not change the behavior, AFAIU, because
`before`, `after`, `run_if` and `ambiguous_with` are transitive
properties from a set to its members.
- The newly added `AnonymousSystemSet` stores the names of its members
to provide better error messages.
- The names are stored in a reference counted slice, allowing fast
clones of the `AnonymousSystemSet`.
- However, only the pointer of the slice is used for hash and equality
operations
- This ensures that two `AnonymousSystemSet` are not equal, even if they
have the same members / member names.
- So two identical `add_systems` calls will produce two different
`AnonymousSystemSet`s.
- Clones of the same `AnonymousSystemSet` will be equal.
## Drawbacks
If my assumptions are correct, the observed behavior should stay the
same. But the number of system sets in the `Schedule` will increase with
each `add_systems` call. If this has negative performance implications,
`add_systems` could be changed to only create the implicit system set if
necessary / when a run condition was added.
---------
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
The trait `IntoSystemConfig<>` requires each implementer to repeat every single member method, even though they can all be implemented by just deferring to `SystemConfig`.
## Solution
Add default implementations to most member methods.
# Objective
Base sets, added in #7466 are a special type of system set. Systems can only be added to base sets via `in_base_set`, while non-base sets can only be added via `in_set`. Unfortunately this is currently guarded by a runtime panic, which presents an unfortunate toe-stub when the wrong method is used. The delayed response between writing code and encountering the error (possibly hours) makes the distinction between base sets and other sets much more difficult to learn.
## Solution
Add the marker traits `BaseSystemSet` and `FreeSystemSet`. `in_base_set` and `in_set` now respectively accept these traits, which moves the runtime panic to a compile time error.
---
## Changelog
+ Added the marker trait `BaseSystemSet`, which is distinguished from a `FreeSystemSet`. These are both subtraits of `SystemSet`.
## Migration Guide
None if merged with 0.10
# Objective
There is a panic that occurs when creating a run condition that accesses `NonSend` resources, but it refers to them as 'thread-local' resources instead.
## Solution
Correct the terminology.
# Objective
Support the following syntax for adding systems:
```rust
App::new()
.add_system(setup.on_startup())
.add_systems((
show_menu.in_schedule(OnEnter(GameState::Paused)),
menu_ssytem.in_set(OnUpdate(GameState::Paused)),
hide_menu.in_schedule(OnExit(GameState::Paused)),
))
```
## Solution
Add the traits `IntoSystemAppConfig{s}`, which provide the extension methods necessary for configuring which schedule a system belongs to. These extension methods return `IntoSystemAppConfig{s}`, which `App::add_system{s}` uses to choose which schedule to add systems to.
---
## Changelog
+ Added the extension methods `in_schedule(label)` and `on_startup()` for configuring the schedule a system belongs to.
## Future Work
* Replace all uses of `add_startup_system` in the engine.
* Deprecate this method
# Objective
Several places in the ECS use marker generics to avoid overlapping trait implementations, but different places alternately refer to it as `Params` and `Marker`. This is potentially confusing, since it might not be clear that the same pattern is being used. Additionally, users might be misled into thinking that the `Params` type corresponds to the `SystemParam`s of a system.
## Solution
Rename `Params` to `Marker`.
# Objective
- Fixes#7659.
## Solution
- This PR extracted the `distributive_run_if` part of #7676, because it does not require the controversial introduction of anonymous system sets.
- The distinctive name should make the user aware about the differences between `IntoSystemConfig::run_if` and `IntoSystemConfigs::distributive_run_if`.
- The documentation explains in detail the consequences of using the API and possible pit falls when using it.
- A test demonstrates the possibility of changing the condition result, resulting in some of the systems not being run.
---
## Changelog
### Added
- Add `distributive_run_if` to `IntoSystemConfigs` to enable adding a run condition to each system when using `add_systems`.
# Objective
- it would be nice to be able to associate a `NodeId` of a system type set to the `NodeId` of the actual system (used in bevy_mod_debugdump)
## Solution
- make `system_type` return the type id of the system
- that way you can check if a `dyn SystemSet` is the system type set of a `dyn System`
- I don't know if this information is already present somewhere else in the scheduler or if there is a better way to expose it
# Objective
- Fixes#5432
- Fixes#6680
## Solution
- move code responsible for generating the `impl TypeUuid` from `type_uuid_derive` into a new function, `gen_impl_type_uuid`.
- this allows the new proc macro, `impl_type_uuid`, to call the code for generation.
- added struct `TypeUuidDef` and implemented `syn::Parse` to allow parsing of the input for the new macro.
- finally, used the new macro `impl_type_uuid` to implement `TypeUuid` for the standard library (in `crates/bevy_reflect/src/type_uuid_impl.rs`).
- fixes#6680 by doing a wrapping add of the param's index to its `TYPE_UUID`
Co-authored-by: dis-da-moe <84386186+dis-da-moe@users.noreply.github.com>
# Objective
Fixes#7632.
As discussed in #7634, it can be quite challenging for users to intuit the mental model of how states now work.
## Solution
Rather than change the behavior of the `OnUpdate` system set, instead work on making sure it's easy to understand what's going on.
Two things have been done:
1. Remove the `.on_update` method from our bevy of system building traits. This was special-cased and made states feel much more magical than they need to.
2. Improve the docs for the `OnUpdate` system set.
