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bevy/crates/bevy_ecs/src/system/commands/mod.rs
Eagster ed7b366b24
Deprecate insert_or_spawn function family (#18147) 
# Objective

Based on #18054, this PR builds on #18035 to deprecate:

- `Commands::insert_or_spawn_batch`
- `Entities::alloc_at_without_replacement`
- `Entities::alloc_at`
- `World::insert_or_spawn_batch`
- `World::insert_or_spawn_batch_with_caller`

## Testing

Just deprecation, so no new tests. Note that as of writing #18035 is
still under testing and review.

## Open Questions

- [x] Should `entity::AllocAtWithoutReplacement` be deprecated? It is
internal and only used in `Entities::alloc_at_without_replacement`.
**EDIT:** Now deprecated.

## Migration Guide

The following functions have been deprecated:

- `Commands::insert_or_spawn_batch`
- `World::insert_or_spawn_batch`
- `World::insert_or_spawn_batch_with_caller`

These functions, when used incorrectly, can cause major performance
problems and are generally viewed as anti-patterns and foot guns. These
are planned to be removed altogether in 0.17.

Instead of these functions consider doing one of the following:

Option A) Instead of despawing entities and re-spawning them at a
particular id, insert the new `Disabled` component without despawning
the entity, and use `try_insert_batch` or `insert_batch` and remove
`Disabled` instead of re-spawning it.

Option B) Instead of giving special meaning to an entity id, simply use
`spawn_batch` and ensure entity references are valid when despawning.

---------

Co-authored-by: JaySpruce <jsprucebruce@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2025-03-06 17:04:16 +00:00

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pub mod command;
pub mod entity_command;
pub mod error_handler;
#[cfg(feature = "std")]
mod parallel_scope;
pub use command::Command;
pub use entity_command::EntityCommand;
#[cfg(feature = "std")]
pub use parallel_scope::*;
use alloc::boxed::Box;
use core::marker::PhantomData;
use log::error;
use crate::{
self as bevy_ecs,
bundle::{Bundle, InsertMode, NoBundleEffect},
change_detection::{MaybeLocation, Mut},
component::{Component, ComponentId, Mutable},
entity::{Entities, Entity, EntityClonerBuilder, EntityDoesNotExistError},
event::Event,
observer::{Observer, TriggerTargets},
resource::Resource,
result::Error,
schedule::ScheduleLabel,
system::{
command::HandleError, entity_command::CommandWithEntity, input::SystemInput, Deferred,
IntoObserverSystem, IntoSystem, RegisteredSystem, SystemId,
},
world::{
command_queue::RawCommandQueue, unsafe_world_cell::UnsafeWorldCell, CommandQueue,
EntityWorldMut, FromWorld, World,
},
};
/// A [`Command`] queue to perform structural changes to the [`World`].
///
/// Since each command requires exclusive access to the `World`,
/// all queued commands are automatically applied in sequence
/// when the `ApplyDeferred` system runs (see [`ApplyDeferred`] documentation for more details).
///
/// Each command can be used to modify the [`World`] in arbitrary ways:
/// * spawning or despawning entities
/// * inserting components on new or existing entities
/// * inserting resources
/// * etc.
///
/// For a version of [`Commands`] that works in parallel contexts (such as
/// within [`Query::par_iter`](crate::system::Query::par_iter)) see
/// [`ParallelCommands`]
///
/// # Usage
///
/// Add `mut commands: Commands` as a function argument to your system to get a
/// copy of this struct that will be applied the next time a copy of [`ApplyDeferred`] runs.
/// Commands are almost always used as a [`SystemParam`](crate::system::SystemParam).
///
/// ```
/// # use bevy_ecs::prelude::*;
/// #
/// fn my_system(mut commands: Commands) {
/// // ...
/// }
/// # bevy_ecs::system::assert_is_system(my_system);
/// ```
///
/// # Implementing
///
/// Each built-in command is implemented as a separate method, e.g. [`Commands::spawn`].
/// In addition to the pre-defined command methods, you can add commands with any arbitrary
/// behavior using [`Commands::queue`], which accepts any type implementing [`Command`].
///
/// Since closures and other functions implement this trait automatically, this allows one-shot,
/// anonymous custom commands.
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # fn foo(mut commands: Commands) {
/// // NOTE: type inference fails here, so annotations are required on the closure.
/// commands.queue(|w: &mut World| {
/// // Mutate the world however you want...
/// });
/// # }
/// ```
///
/// # Error handling
///
/// A [`Command`] can return a [`Result`](crate::result::Result),
/// which will be passed to an error handler if the `Result` is an error.
///
/// Error handlers are functions/closures of the form `fn(&mut World, Error)`.
/// They are granted exclusive access to the [`World`], which enables them to
/// respond to the error in whatever way is necessary.
///
/// The [default error handler](error_handler::default) panics.
/// It can be configured by enabling the `configurable_error_handler` cargo feature,
/// then setting the `GLOBAL_ERROR_HANDLER`.
///
/// Alternatively, you can customize the error handler for a specific command
/// by calling [`Commands::queue_handled`].
///
/// The [`error_handler`] module provides some simple error handlers for convenience.
///
/// [`ApplyDeferred`]: crate::schedule::ApplyDeferred
pub struct Commands<'w, 's> {
queue: InternalQueue<'s>,
entities: &'w Entities,
}
// SAFETY: All commands [`Command`] implement [`Send`]
unsafe impl Send for Commands<'_, '_> {}
// SAFETY: `Commands` never gives access to the inner commands.
unsafe impl Sync for Commands<'_, '_> {}
const _: () = {
type __StructFieldsAlias<'w, 's> = (Deferred<'s, CommandQueue>, &'w Entities);
#[doc(hidden)]
pub struct FetchState {
state: <__StructFieldsAlias<'static, 'static> as bevy_ecs::system::SystemParam>::State,
}
// SAFETY: Only reads Entities
unsafe impl bevy_ecs::system::SystemParam for Commands<'_, '_> {
type State = FetchState;
type Item<'w, 's> = Commands<'w, 's>;
fn init_state(
world: &mut World,
system_meta: &mut bevy_ecs::system::SystemMeta,
) -> Self::State {
FetchState {
state: <__StructFieldsAlias<'_, '_> as bevy_ecs::system::SystemParam>::init_state(
world,
system_meta,
),
}
}
unsafe fn new_archetype(
state: &mut Self::State,
archetype: &bevy_ecs::archetype::Archetype,
system_meta: &mut bevy_ecs::system::SystemMeta,
) {
// SAFETY: Caller guarantees the archetype is from the world used in `init_state`
unsafe {
<__StructFieldsAlias<'_, '_> as bevy_ecs::system::SystemParam>::new_archetype(
&mut state.state,
archetype,
system_meta,
);
};
}
fn apply(
state: &mut Self::State,
system_meta: &bevy_ecs::system::SystemMeta,
world: &mut World,
) {
<__StructFieldsAlias<'_, '_> as bevy_ecs::system::SystemParam>::apply(
&mut state.state,
system_meta,
world,
);
}
fn queue(
state: &mut Self::State,
system_meta: &bevy_ecs::system::SystemMeta,
world: bevy_ecs::world::DeferredWorld,
) {
<__StructFieldsAlias<'_, '_> as bevy_ecs::system::SystemParam>::queue(
&mut state.state,
system_meta,
world,
);
}
#[inline]
unsafe fn validate_param(
state: &Self::State,
system_meta: &bevy_ecs::system::SystemMeta,
world: UnsafeWorldCell,
) -> bool {
<(Deferred<CommandQueue>, &Entities) as bevy_ecs::system::SystemParam>::validate_param(
&state.state,
system_meta,
world,
)
}
#[inline]
unsafe fn get_param<'w, 's>(
state: &'s mut Self::State,
system_meta: &bevy_ecs::system::SystemMeta,
world: UnsafeWorldCell<'w>,
change_tick: bevy_ecs::component::Tick,
) -> Self::Item<'w, 's> {
let(f0, f1) = <(Deferred<'s, CommandQueue>, &'w Entities) as bevy_ecs::system::SystemParam>::get_param(&mut state.state, system_meta, world, change_tick);
Commands {
queue: InternalQueue::CommandQueue(f0),
entities: f1,
}
}
}
// SAFETY: Only reads Entities
unsafe impl<'w, 's> bevy_ecs::system::ReadOnlySystemParam for Commands<'w, 's>
where
Deferred<'s, CommandQueue>: bevy_ecs::system::ReadOnlySystemParam,
&'w Entities: bevy_ecs::system::ReadOnlySystemParam,
{
}
};
enum InternalQueue<'s> {
CommandQueue(Deferred<'s, CommandQueue>),
RawCommandQueue(RawCommandQueue),
}
impl<'w, 's> Commands<'w, 's> {
/// Returns a new `Commands` instance from a [`CommandQueue`] and a [`World`].
///
/// It is not required to call this constructor when using `Commands` as a [system parameter].
///
/// [system parameter]: crate::system::SystemParam
pub fn new(queue: &'s mut CommandQueue, world: &'w World) -> Self {
Self::new_from_entities(queue, &world.entities)
}
/// Returns a new `Commands` instance from a [`CommandQueue`] and an [`Entities`] reference.
///
/// It is not required to call this constructor when using `Commands` as a [system parameter].
///
/// [system parameter]: crate::system::SystemParam
pub fn new_from_entities(queue: &'s mut CommandQueue, entities: &'w Entities) -> Self {
Self {
queue: InternalQueue::CommandQueue(Deferred(queue)),
entities,
}
}
/// Returns a new `Commands` instance from a [`RawCommandQueue`] and an [`Entities`] reference.
///
/// This is used when constructing [`Commands`] from a [`DeferredWorld`](crate::world::DeferredWorld).
///
/// # Safety
///
/// * Caller ensures that `queue` must outlive 'w
pub(crate) unsafe fn new_raw_from_entities(
queue: RawCommandQueue,
entities: &'w Entities,
) -> Self {
Self {
queue: InternalQueue::RawCommandQueue(queue),
entities,
}
}
/// Returns a [`Commands`] with a smaller lifetime.
/// This is useful if you have `&mut Commands` but need `Commands`.
///
/// # Examples
///
/// ```
/// # use bevy_ecs::prelude::*;
/// fn my_system(mut commands: Commands) {
/// // We do our initialization in a separate function,
/// // which expects an owned `Commands`.
/// do_initialization(commands.reborrow());
///
/// // Since we only reborrowed the commands instead of moving them, we can still use them.
/// commands.spawn_empty();
/// }
/// #
/// # fn do_initialization(_: Commands) {}
/// ```
pub fn reborrow(&mut self) -> Commands<'w, '_> {
Commands {
queue: match &mut self.queue {
InternalQueue::CommandQueue(queue) => InternalQueue::CommandQueue(queue.reborrow()),
InternalQueue::RawCommandQueue(queue) => {
InternalQueue::RawCommandQueue(queue.clone())
}
},
entities: self.entities,
}
}
/// Take all commands from `other` and append them to `self`, leaving `other` empty
pub fn append(&mut self, other: &mut CommandQueue) {
match &mut self.queue {
InternalQueue::CommandQueue(queue) => queue.bytes.append(&mut other.bytes),
InternalQueue::RawCommandQueue(queue) => {
// SAFETY: Pointers in `RawCommandQueue` are never null
unsafe { queue.bytes.as_mut() }.append(&mut other.bytes);
}
}
}
/// Reserves a new empty [`Entity`] to be spawned, and returns its corresponding [`EntityCommands`].
///
/// See [`World::spawn_empty`] for more details.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
///
/// #[derive(Component)]
/// struct Label(&'static str);
/// #[derive(Component)]
/// struct Strength(u32);
/// #[derive(Component)]
/// struct Agility(u32);
///
/// fn example_system(mut commands: Commands) {
/// // Create a new empty entity and retrieve its id.
/// let empty_entity = commands.spawn_empty().id();
///
/// // Create another empty entity, then add some component to it
/// commands.spawn_empty()
/// // adds a new component bundle to the entity
/// .insert((Strength(1), Agility(2)))
/// // adds a single component to the entity
/// .insert(Label("hello world"));
/// }
/// # bevy_ecs::system::assert_is_system(example_system);
/// ```
///
/// # See also
///
/// - [`spawn`](Self::spawn) to spawn an entity with a bundle.
/// - [`spawn_batch`](Self::spawn_batch) to spawn entities with a bundle each.
pub fn spawn_empty(&mut self) -> EntityCommands {
let entity = self.entities.reserve_entity();
EntityCommands {
entity,
commands: self.reborrow(),
}
}
/// Pushes a [`Command`] to the queue for creating a new entity with the given [`Bundle`]'s components,
/// and returns its corresponding [`EntityCommands`].
///
/// In case multiple bundles of the same [`Bundle`] type need to be spawned,
/// [`spawn_batch`](Self::spawn_batch) should be used for better performance.
///
/// # Example
///
/// ```
/// use bevy_ecs::prelude::*;
///
/// #[derive(Component)]
/// struct Component1;
/// #[derive(Component)]
/// struct Component2;
/// #[derive(Component)]
/// struct Label(&'static str);
/// #[derive(Component)]
/// struct Strength(u32);
/// #[derive(Component)]
/// struct Agility(u32);
///
/// #[derive(Bundle)]
/// struct ExampleBundle {
/// a: Component1,
/// b: Component2,
/// }
///
/// fn example_system(mut commands: Commands) {
/// // Create a new entity with a single component.
/// commands.spawn(Component1);
///
/// // Create a new entity with a component bundle.
/// commands.spawn(ExampleBundle {
/// a: Component1,
/// b: Component2,
/// });
///
/// commands
/// // Create a new entity with two components using a "tuple bundle".
/// .spawn((Component1, Component2))
/// // `spawn returns a builder, so you can insert more bundles like this:
/// .insert((Strength(1), Agility(2)))
/// // or insert single components like this:
/// .insert(Label("hello world"));
/// }
/// # bevy_ecs::system::assert_is_system(example_system);
/// ```
///
/// # See also
///
/// - [`spawn_empty`](Self::spawn_empty) to spawn an entity without any components.
/// - [`spawn_batch`](Self::spawn_batch) to spawn entities with a bundle each.
#[track_caller]
pub fn spawn<T: Bundle>(&mut self, bundle: T) -> EntityCommands {
let mut entity = self.spawn_empty();
entity.insert(bundle);
entity
}
/// Returns the [`EntityCommands`] for the requested [`Entity`].
///
/// This method does not guarantee that commands queued by the returned `EntityCommands`
/// will be successful, since the entity could be despawned before they are executed.
///
/// # Example
///
/// ```
/// use bevy_ecs::prelude::*;
///
/// #[derive(Component)]
/// struct Label(&'static str);
/// #[derive(Component)]
/// struct Strength(u32);
/// #[derive(Component)]
/// struct Agility(u32);
///
/// fn example_system(mut commands: Commands) {
/// // Create a new, empty entity
/// let entity = commands.spawn_empty().id();
///
/// commands.entity(entity)
/// // adds a new component bundle to the entity
/// .insert((Strength(1), Agility(2)))
/// // adds a single component to the entity
/// .insert(Label("hello world"));
/// }
/// # bevy_ecs::system::assert_is_system(example_system);
/// ```
///
/// # See also
///
/// - [`get_entity`](Self::get_entity) for the fallible version.
#[inline]
#[track_caller]
pub fn entity(&mut self, entity: Entity) -> EntityCommands {
EntityCommands {
entity,
commands: self.reborrow(),
}
}
/// Returns the [`EntityCommands`] for the requested [`Entity`], if it exists.
///
/// This method does not guarantee that commands queued by the returned `EntityCommands`
/// will be successful, since the entity could be despawned before they are executed.
///
/// # Errors
///
/// Returns [`EntityDoesNotExistError`] if the requested entity does not exist.
///
/// # Example
///
/// ```
/// use bevy_ecs::prelude::*;
///
/// #[derive(Component)]
/// struct Label(&'static str);
/// fn example_system(mut commands: Commands) -> Result {
/// // Create a new, empty entity.
/// let entity = commands.spawn_empty().id();
///
/// // Get the entity if it still exists, which it will in this case.
/// // If it didn't, the `?` operator would propagate the returned error
/// // to the system, and the system would pass it to an error handler.
/// let mut entity_commands = commands.get_entity(entity)?;
///
/// // Add a single component to the entity.
/// entity_commands.insert(Label("hello world"));
///
/// // Return from the system with a success.
/// Ok(())
/// }
/// # bevy_ecs::system::assert_is_system(example_system);
/// ```
///
/// # See also
///
/// - [`entity`](Self::entity) for the infallible version.
#[inline]
#[track_caller]
pub fn get_entity(
&mut self,
entity: Entity,
) -> Result<EntityCommands, EntityDoesNotExistError> {
if self.entities.contains(entity) {
Ok(EntityCommands {
entity,
commands: self.reborrow(),
})
} else {
Err(EntityDoesNotExistError::new(entity, self.entities))
}
}
/// Pushes a [`Command`] to the queue for creating entities with a particular [`Bundle`] type.
///
/// `bundles_iter` is a type that can be converted into a [`Bundle`] iterator
/// (it can also be a collection).
///
/// This method is equivalent to iterating `bundles_iter`
/// and calling [`spawn`](Self::spawn) on each bundle,
/// but it is faster due to memory pre-allocation.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// #
/// # #[derive(Component)]
/// # struct Name(String);
/// # #[derive(Component)]
/// # struct Score(u32);
/// #
/// # fn system(mut commands: Commands) {
/// commands.spawn_batch(vec![
/// (
/// Name("Alice".to_string()),
/// Score(0),
/// ),
/// (
/// Name("Bob".to_string()),
/// Score(0),
/// ),
/// ]);
/// # }
/// # bevy_ecs::system::assert_is_system(system);
/// ```
///
/// # See also
///
/// - [`spawn`](Self::spawn) to spawn an entity with a bundle.
/// - [`spawn_empty`](Self::spawn_empty) to spawn an entity without any components.
#[track_caller]
pub fn spawn_batch<I>(&mut self, bundles_iter: I)
where
I: IntoIterator + Send + Sync + 'static,
I::Item: Bundle<Effect: NoBundleEffect>,
{
self.queue(command::spawn_batch(bundles_iter));
}
/// Pushes a generic [`Command`] to the command queue.
///
/// If the [`Command`] returns a [`Result`],
/// it will be handled using the [default error handler](error_handler::default).
///
/// To use a custom error handler, see [`Commands::queue_handled`].
///
/// The command can be:
/// - A custom struct that implements [`Command`].
/// - A closure or function that matches one of the following signatures:
/// - [`(&mut World)`](World)
/// - A built-in command from the [`command`] module.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// #[derive(Resource, Default)]
/// struct Counter(u64);
///
/// struct AddToCounter(String);
///
/// impl Command<Result> for AddToCounter {
/// fn apply(self, world: &mut World) -> Result {
/// let mut counter = world.get_resource_or_insert_with(Counter::default);
/// let amount: u64 = self.0.parse()?;
/// counter.0 += amount;
/// Ok(())
/// }
/// }
///
/// fn add_three_to_counter_system(mut commands: Commands) {
/// commands.queue(AddToCounter("3".to_string()));
/// }
/// fn add_twenty_five_to_counter_system(mut commands: Commands) {
/// commands.queue(|world: &mut World| {
/// let mut counter = world.get_resource_or_insert_with(Counter::default);
/// counter.0 += 25;
/// });
/// }
/// # bevy_ecs::system::assert_is_system(add_three_to_counter_system);
/// # bevy_ecs::system::assert_is_system(add_twenty_five_to_counter_system);
/// ```
pub fn queue<C: Command<T> + HandleError<T>, T>(&mut self, command: C) {
self.queue_internal(command.handle_error());
}
/// Pushes a generic [`Command`] to the command queue.
///
/// If the [`Command`] returns a [`Result`],
/// the given `error_handler` will be used to handle error cases.
///
/// To implicitly use the default error handler, see [`Commands::queue`].
///
/// The command can be:
/// - A custom struct that implements [`Command`].
/// - A closure or function that matches one of the following signatures:
/// - [`(&mut World)`](World)
/// - [`(&mut World)`](World) `->` [`Result`]
/// - A built-in command from the [`command`] module.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # use bevy_ecs::system::error_handler;
/// #[derive(Resource, Default)]
/// struct Counter(u64);
///
/// struct AddToCounter(String);
///
/// impl Command<Result> for AddToCounter {
/// fn apply(self, world: &mut World) -> Result {
/// let mut counter = world.get_resource_or_insert_with(Counter::default);
/// let amount: u64 = self.0.parse()?;
/// counter.0 += amount;
/// Ok(())
/// }
/// }
///
/// fn add_three_to_counter_system(mut commands: Commands) {
/// commands.queue_handled(AddToCounter("3".to_string()), error_handler::warn());
/// }
/// fn add_twenty_five_to_counter_system(mut commands: Commands) {
/// commands.queue(|world: &mut World| {
/// let mut counter = world.get_resource_or_insert_with(Counter::default);
/// counter.0 += 25;
/// });
/// }
/// # bevy_ecs::system::assert_is_system(add_three_to_counter_system);
/// # bevy_ecs::system::assert_is_system(add_twenty_five_to_counter_system);
/// ```
pub fn queue_handled<C: Command<T> + HandleError<T>, T>(
&mut self,
command: C,
error_handler: fn(&mut World, Error),
) {
self.queue_internal(command.handle_error_with(error_handler));
}
fn queue_internal(&mut self, command: impl Command) {
match &mut self.queue {
InternalQueue::CommandQueue(queue) => {
queue.push(command);
}
InternalQueue::RawCommandQueue(queue) => {
// SAFETY: `RawCommandQueue` is only every constructed in `Commands::new_raw_from_entities`
// where the caller of that has ensured that `queue` outlives `self`
unsafe {
queue.push(command);
}
}
}
}
/// Pushes a [`Command`] to the queue for creating entities, if needed,
/// and for adding a bundle to each entity.
///
/// `bundles_iter` is a type that can be converted into an ([`Entity`], [`Bundle`]) iterator
/// (it can also be a collection).
///
/// When the command is applied,
/// for each (`Entity`, `Bundle`) pair in the given `bundles_iter`,
/// the `Entity` is spawned, if it does not exist already.
/// Then, the `Bundle` is added to the entity.
///
/// This method is equivalent to iterating `bundles_iter`,
/// calling [`spawn`](Self::spawn) for each bundle,
/// and passing it to [`insert`](EntityCommands::insert),
/// but it is faster due to memory pre-allocation.
///
/// # Note
///
/// Spawning a specific `entity` value is rarely the right choice. Most apps should use [`Commands::spawn_batch`].
/// This method should generally only be used for sharing entities across apps, and only when they have a scheme
/// worked out to share an ID space (which doesn't happen by default).
#[track_caller]
#[deprecated(
note = "This can cause extreme performance problems when used with lots of arbitrary free entities. See #18054 on GitHub."
)]
pub fn insert_or_spawn_batch<I, B>(&mut self, bundles_iter: I)
where
I: IntoIterator<Item = (Entity, B)> + Send + Sync + 'static,
B: Bundle<Effect: NoBundleEffect>,
{
let caller = MaybeLocation::caller();
self.queue(move |world: &mut World| {
#[expect(
deprecated,
reason = "This needs to be supported for now, and the outer item is deprecated too."
)]
if let Err(invalid_entities) = world.insert_or_spawn_batch_with_caller(
bundles_iter,
caller,
) {
error!(
"{caller}: Failed to 'insert or spawn' bundle of type {} into the following invalid entities: {:?}",
core::any::type_name::<B>(),
invalid_entities
);
}
});
}
/// Pushes a [`Command`] to the queue for adding a [`Bundle`] type to a batch of [`Entities`](Entity).
///
/// A batch can be any type that implements [`IntoIterator`] containing `(Entity, Bundle)` tuples,
/// such as a [`Vec<(Entity, Bundle)>`](alloc::vec::Vec) or an array `[(Entity, Bundle); N]`.
///
/// When the command is applied, for each `(Entity, Bundle)` pair in the given batch,
/// the `Bundle` is added to the `Entity`, overwriting any existing components shared by the `Bundle`.
///
/// This method is equivalent to iterating the batch,
/// calling [`entity`](Self::entity) for each pair,
/// and passing the bundle to [`insert`](EntityCommands::insert),
/// but it is faster due to memory pre-allocation.
///
/// # Panics
///
/// This command panics if any of the given entities do not exist.
///
/// For the non-panicking version, see [`try_insert_batch`](Self::try_insert_batch).
#[track_caller]
pub fn insert_batch<I, B>(&mut self, batch: I)
where
I: IntoIterator<Item = (Entity, B)> + Send + Sync + 'static,
B: Bundle<Effect: NoBundleEffect>,
{
self.queue(command::insert_batch(batch, InsertMode::Replace));
}
/// Pushes a [`Command`] to the queue for adding a [`Bundle`] type to a batch of [`Entities`](Entity).
///
/// A batch can be any type that implements [`IntoIterator`] containing `(Entity, Bundle)` tuples,
/// such as a [`Vec<(Entity, Bundle)>`](alloc::vec::Vec) or an array `[(Entity, Bundle); N]`.
///
/// When the command is applied, for each `(Entity, Bundle)` pair in the given batch,
/// the `Bundle` is added to the `Entity`, except for any components already present on the `Entity`.
///
/// This method is equivalent to iterating the batch,
/// calling [`entity`](Self::entity) for each pair,
/// and passing the bundle to [`insert_if_new`](EntityCommands::insert_if_new),
/// but it is faster due to memory pre-allocation.
///
/// # Panics
///
/// This command panics if any of the given entities do not exist.
///
/// For the non-panicking version, see [`try_insert_batch_if_new`](Self::try_insert_batch_if_new).
#[track_caller]
pub fn insert_batch_if_new<I, B>(&mut self, batch: I)
where
I: IntoIterator<Item = (Entity, B)> + Send + Sync + 'static,
B: Bundle<Effect: NoBundleEffect>,
{
self.queue(command::insert_batch(batch, InsertMode::Keep));
}
/// Pushes a [`Command`] to the queue for adding a [`Bundle`] type to a batch of [`Entities`](Entity).
///
/// A batch can be any type that implements [`IntoIterator`] containing `(Entity, Bundle)` tuples,
/// such as a [`Vec<(Entity, Bundle)>`](alloc::vec::Vec) or an array `[(Entity, Bundle); N]`.
///
/// When the command is applied, for each `(Entity, Bundle)` pair in the given batch,
/// the `Bundle` is added to the `Entity`, overwriting any existing components shared by the `Bundle`.
///
/// This method is equivalent to iterating the batch,
/// calling [`get_entity`](Self::get_entity) for each pair,
/// and passing the bundle to [`insert`](EntityCommands::insert),
/// but it is faster due to memory pre-allocation.
///
/// This command will send a warning if any of the given entities do not exist.
///
/// For the panicking version, see [`insert_batch`](Self::insert_batch).
#[track_caller]
pub fn try_insert_batch<I, B>(&mut self, batch: I)
where
I: IntoIterator<Item = (Entity, B)> + Send + Sync + 'static,
B: Bundle<Effect: NoBundleEffect>,
{
self.queue(
command::insert_batch(batch, InsertMode::Replace)
.handle_error_with(error_handler::warn()),
);
}
/// Pushes a [`Command`] to the queue for adding a [`Bundle`] type to a batch of [`Entities`](Entity).
///
/// A batch can be any type that implements [`IntoIterator`] containing `(Entity, Bundle)` tuples,
/// such as a [`Vec<(Entity, Bundle)>`](alloc::vec::Vec) or an array `[(Entity, Bundle); N]`.
///
/// When the command is applied, for each `(Entity, Bundle)` pair in the given batch,
/// the `Bundle` is added to the `Entity`, except for any components already present on the `Entity`.
///
/// This method is equivalent to iterating the batch,
/// calling [`get_entity`](Self::get_entity) for each pair,
/// and passing the bundle to [`insert_if_new`](EntityCommands::insert_if_new),
/// but it is faster due to memory pre-allocation.
///
/// This command will send a warning if any of the given entities do not exist.
///
/// For the panicking version, see [`insert_batch_if_new`](Self::insert_batch_if_new).
#[track_caller]
pub fn try_insert_batch_if_new<I, B>(&mut self, batch: I)
where
I: IntoIterator<Item = (Entity, B)> + Send + Sync + 'static,
B: Bundle<Effect: NoBundleEffect>,
{
self.queue(
command::insert_batch(batch, InsertMode::Keep).handle_error_with(error_handler::warn()),
);
}
/// Pushes a [`Command`] to the queue for inserting a [`Resource`] in the [`World`] with an inferred value.
///
/// The inferred value is determined by the [`FromWorld`] trait of the resource.
/// When the command is applied,
/// if the resource already exists, nothing happens.
///
/// See [`World::init_resource`] for more details.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// #
/// # #[derive(Resource, Default)]
/// # struct Scoreboard {
/// # current_score: u32,
/// # high_score: u32,
/// # }
/// #
/// # fn initialize_scoreboard(mut commands: Commands) {
/// commands.init_resource::<Scoreboard>();
/// # }
/// # bevy_ecs::system::assert_is_system(initialize_scoreboard);
/// ```
#[track_caller]
pub fn init_resource<R: Resource + FromWorld>(&mut self) {
self.queue(command::init_resource::<R>());
}
/// Pushes a [`Command`] to the queue for inserting a [`Resource`] in the [`World`] with a specific value.
///
/// This will overwrite any previous value of the same resource type.
///
/// See [`World::insert_resource`] for more details.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// #
/// # #[derive(Resource)]
/// # struct Scoreboard {
/// # current_score: u32,
/// # high_score: u32,
/// # }
/// #
/// # fn system(mut commands: Commands) {
/// commands.insert_resource(Scoreboard {
/// current_score: 0,
/// high_score: 0,
/// });
/// # }
/// # bevy_ecs::system::assert_is_system(system);
/// ```
#[track_caller]
pub fn insert_resource<R: Resource>(&mut self, resource: R) {
self.queue(command::insert_resource(resource));
}
/// Pushes a [`Command`] to the queue for removing a [`Resource`] from the [`World`].
///
/// See [`World::remove_resource`] for more details.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// #
/// # #[derive(Resource)]
/// # struct Scoreboard {
/// # current_score: u32,
/// # high_score: u32,
/// # }
/// #
/// # fn system(mut commands: Commands) {
/// commands.remove_resource::<Scoreboard>();
/// # }
/// # bevy_ecs::system::assert_is_system(system);
/// ```
pub fn remove_resource<R: Resource>(&mut self) {
self.queue(command::remove_resource::<R>());
}
/// Runs the system corresponding to the given [`SystemId`].
/// Systems are ran in an exclusive and single threaded way.
/// Running slow systems can become a bottleneck.
///
/// Calls [`World::run_system`](World::run_system).
///
/// There is no way to get the output of a system when run as a command, because the
/// execution of the system happens later. To get the output of a system, use
/// [`World::run_system`] or [`World::run_system_with`] instead of running the system as a command.
pub fn run_system(&mut self, id: SystemId) {
self.queue(command::run_system(id).handle_error_with(error_handler::warn()));
}
/// Runs the system corresponding to the given [`SystemId`].
/// Systems are ran in an exclusive and single threaded way.
/// Running slow systems can become a bottleneck.
///
/// Calls [`World::run_system_with`](World::run_system_with).
///
/// There is no way to get the output of a system when run as a command, because the
/// execution of the system happens later. To get the output of a system, use
/// [`World::run_system`] or [`World::run_system_with`] instead of running the system as a command.
pub fn run_system_with<I>(&mut self, id: SystemId<I>, input: I::Inner<'static>)
where
I: SystemInput<Inner<'static>: Send> + 'static,
{
self.queue(command::run_system_with(id, input).handle_error_with(error_handler::warn()));
}
/// Registers a system and returns a [`SystemId`] so it can later be called by [`World::run_system`].
///
/// It's possible to register the same systems more than once, they'll be stored separately.
///
/// This is different from adding systems to a [`Schedule`](crate::schedule::Schedule),
/// because the [`SystemId`] that is returned can be used anywhere in the [`World`] to run the associated system.
/// This allows for running systems in a push-based fashion.
/// Using a [`Schedule`](crate::schedule::Schedule) is still preferred for most cases
/// due to its better performance and ability to run non-conflicting systems simultaneously.
///
/// If you want to prevent Commands from registering the same system multiple times, consider using [`Local`](crate::system::Local)
///
/// # Example
///
/// ```
/// # use bevy_ecs::{prelude::*, world::CommandQueue, system::SystemId};
///
/// #[derive(Resource)]
/// struct Counter(i32);
///
/// fn register_system(mut local_system: Local<Option<SystemId>>, mut commands: Commands) {
/// if let Some(system) = *local_system {
/// commands.run_system(system);
/// } else {
/// *local_system = Some(commands.register_system(increment_counter));
/// }
/// }
///
/// fn increment_counter(mut value: ResMut<Counter>) {
/// value.0 += 1;
/// }
///
/// # let mut world = World::default();
/// # world.insert_resource(Counter(0));
/// # let mut queue_1 = CommandQueue::default();
/// # let systemid = {
/// # let mut commands = Commands::new(&mut queue_1, &world);
/// # commands.register_system(increment_counter)
/// # };
/// # let mut queue_2 = CommandQueue::default();
/// # {
/// # let mut commands = Commands::new(&mut queue_2, &world);
/// # commands.run_system(systemid);
/// # }
/// # queue_1.append(&mut queue_2);
/// # queue_1.apply(&mut world);
/// # assert_eq!(1, world.resource::<Counter>().0);
/// # bevy_ecs::system::assert_is_system(register_system);
/// ```
pub fn register_system<I, O, M>(
&mut self,
system: impl IntoSystem<I, O, M> + 'static,
) -> SystemId<I, O>
where
I: SystemInput + Send + 'static,
O: Send + 'static,
{
let entity = self.spawn_empty().id();
let system = RegisteredSystem::<I, O>::new(Box::new(IntoSystem::into_system(system)));
self.entity(entity).insert(system);
SystemId::from_entity(entity)
}
/// Removes a system previously registered with [`Commands::register_system`] or [`World::register_system`].
///
/// See [`World::unregister_system`] for more information.
pub fn unregister_system<I, O>(&mut self, system_id: SystemId<I, O>)
where
I: SystemInput + Send + 'static,
O: Send + 'static,
{
self.queue(command::unregister_system(system_id).handle_error_with(error_handler::warn()));
}
/// Removes a system previously registered with [`World::register_system_cached`].
///
/// See [`World::unregister_system_cached`] for more information.
pub fn unregister_system_cached<
I: SystemInput + Send + 'static,
O: 'static,
M: 'static,
S: IntoSystem<I, O, M> + Send + 'static,
>(
&mut self,
system: S,
) {
self.queue(
command::unregister_system_cached(system).handle_error_with(error_handler::warn()),
);
}
/// Similar to [`Self::run_system`], but caching the [`SystemId`] in a
/// [`CachedSystemId`](crate::system::CachedSystemId) resource.
///
/// See [`World::register_system_cached`] for more information.
pub fn run_system_cached<M: 'static, S: IntoSystem<(), (), M> + Send + 'static>(
&mut self,
system: S,
) {
self.queue(command::run_system_cached(system).handle_error_with(error_handler::warn()));
}
/// Similar to [`Self::run_system_with`], but caching the [`SystemId`] in a
/// [`CachedSystemId`](crate::system::CachedSystemId) resource.
///
/// See [`World::register_system_cached`] for more information.
pub fn run_system_cached_with<I, M, S>(&mut self, system: S, input: I::Inner<'static>)
where
I: SystemInput<Inner<'static>: Send> + Send + 'static,
M: 'static,
S: IntoSystem<I, (), M> + Send + 'static,
{
self.queue(
command::run_system_cached_with(system, input).handle_error_with(error_handler::warn()),
);
}
/// Sends a "global" [`Trigger`] without any targets. This will run any [`Observer`] of the `event` that
/// isn't scoped to specific targets.
///
/// [`Trigger`]: crate::observer::Trigger
#[track_caller]
pub fn trigger(&mut self, event: impl Event) {
self.queue(command::trigger(event));
}
/// Sends a [`Trigger`] for the given targets. This will run any [`Observer`] of the `event` that
/// watches those targets.
///
/// [`Trigger`]: crate::observer::Trigger
#[track_caller]
pub fn trigger_targets(
&mut self,
event: impl Event,
targets: impl TriggerTargets + Send + Sync + 'static,
) {
self.queue(command::trigger_targets(event, targets));
}
/// Spawns an [`Observer`] and returns the [`EntityCommands`] associated
/// with the entity that stores the observer.
///
/// **Calling [`observe`](EntityCommands::observe) on the returned
/// [`EntityCommands`] will observe the observer itself, which you very
/// likely do not want.**
pub fn add_observer<E: Event, B: Bundle, M>(
&mut self,
observer: impl IntoObserverSystem<E, B, M>,
) -> EntityCommands {
self.spawn(Observer::new(observer))
}
/// Sends an arbitrary [`Event`].
///
/// This is a convenience method for sending events without requiring an [`EventWriter`].
/// ## Performance
/// Since this is a command, exclusive world access is used, which means that it will not profit from
/// system-level parallelism on supported platforms.
/// If these events are performance-critical or very frequently
/// sent, consider using a typed [`EventWriter`] instead.
///
/// [`EventWriter`]: crate::event::EventWriter
#[track_caller]
pub fn send_event<E: Event>(&mut self, event: E) -> &mut Self {
self.queue(command::send_event(event));
self
}
/// Runs the schedule corresponding to the given [`ScheduleLabel`].
///
/// Calls [`World::try_run_schedule`](World::try_run_schedule).
///
/// This will log an error if the schedule is not available to be run.
///
/// # Examples
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # use bevy_ecs::schedule::ScheduleLabel;
/// #
/// # #[derive(Default, Resource)]
/// # struct Counter(u32);
/// #
/// #[derive(ScheduleLabel, Hash, Debug, PartialEq, Eq, Clone, Copy)]
/// struct FooSchedule;
///
/// # fn foo_system(mut counter: ResMut<Counter>) {
/// # counter.0 += 1;
/// # }
/// #
/// # let mut schedule = Schedule::new(FooSchedule);
/// # schedule.add_systems(foo_system);
/// #
/// # let mut world = World::default();
/// #
/// # world.init_resource::<Counter>();
/// # world.add_schedule(schedule);
/// #
/// # assert_eq!(world.resource::<Counter>().0, 0);
/// #
/// # let mut commands = world.commands();
/// commands.run_schedule(FooSchedule);
/// #
/// # world.flush();
/// #
/// # assert_eq!(world.resource::<Counter>().0, 1);
/// ```
pub fn run_schedule(&mut self, label: impl ScheduleLabel) {
self.queue(command::run_schedule(label).handle_error_with(error_handler::warn()));
}
}
/// A list of commands that will be run to modify an [`Entity`].
///
/// # Note
///
/// Most [`Commands`] (and thereby [`EntityCommands`]) are deferred: when you call the command,
/// if it requires mutable access to the [`World`] (that is, if it removes, adds, or changes something),
/// it's not executed immediately. Instead, the command is added to a "command queue."
/// The command queue is applied between [`Schedules`](crate::schedule::Schedule), one by one,
/// so that each command can have exclusive access to the World.
///
/// # Fallible
///
/// Due to their deferred nature, an entity you're trying to change with an [`EntityCommand`] can be
/// despawned by the time the command is executed. All deferred entity commands will check if the
/// entity exists at the time of execution and will return an error if it doesn't.
///
/// # Error handling
///
/// An [`EntityCommand`] can return a [`Result`](crate::result::Result),
/// which will be passed to an error handler if the `Result` is an error.
///
/// Error handlers are functions/closures of the form `fn(&mut World, Error)`.
/// They are granted exclusive access to the [`World`], which enables them to
/// respond to the error in whatever way is necessary.
///
/// The [default error handler](error_handler::default) panics.
/// It can be configured by enabling the `configurable_error_handler` cargo feature,
/// then setting the `GLOBAL_ERROR_HANDLER`.
///
/// Alternatively, you can customize the error handler for a specific command
/// by calling [`EntityCommands::queue_handled`].
///
/// The [`error_handler`] module provides some simple error handlers for convenience.
pub struct EntityCommands<'a> {
pub(crate) entity: Entity,
pub(crate) commands: Commands<'a, 'a>,
}
impl<'a> EntityCommands<'a> {
/// Returns the [`Entity`] id of the entity.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// #
/// fn my_system(mut commands: Commands) {
/// let entity_id = commands.spawn_empty().id();
/// }
/// # bevy_ecs::system::assert_is_system(my_system);
/// ```
#[inline]
#[must_use = "Omit the .id() call if you do not need to store the `Entity` identifier."]
pub fn id(&self) -> Entity {
self.entity
}
/// Returns an [`EntityCommands`] with a smaller lifetime.
/// This is useful if you have `&mut EntityCommands` but you need `EntityCommands`.
pub fn reborrow(&mut self) -> EntityCommands {
EntityCommands {
entity: self.entity,
commands: self.commands.reborrow(),
}
}
/// Get an [`EntityEntryCommands`] for the [`Component`] `T`,
/// allowing you to modify it or insert it if it isn't already present.
///
/// See also [`insert_if_new`](Self::insert_if_new), which lets you insert a [`Bundle`] without overwriting it.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # #[derive(Resource)]
/// # struct PlayerEntity { entity: Entity }
/// #[derive(Component)]
/// struct Level(u32);
///
/// fn level_up_system(mut commands: Commands, player: Res<PlayerEntity>) {
/// commands
/// .entity(player.entity)
/// .entry::<Level>()
/// // Modify the component if it exists
/// .and_modify(|mut lvl| lvl.0 += 1)
/// // Otherwise insert a default value
/// .or_insert(Level(0));
/// }
/// # bevy_ecs::system::assert_is_system(level_up_system);
/// ```
pub fn entry<T: Component>(&mut self) -> EntityEntryCommands<T> {
EntityEntryCommands {
entity_commands: self.reborrow(),
marker: PhantomData,
}
}
/// Adds a [`Bundle`] of components to the entity.
///
/// This will overwrite any previous value(s) of the same component type.
/// See [`EntityCommands::insert_if_new`] to keep the old value instead.
///
/// # Panics
///
/// The command will panic when applied if the associated entity does not exist.
///
/// To avoid a panic in this case, use the command [`Self::try_insert`] instead.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # #[derive(Resource)]
/// # struct PlayerEntity { entity: Entity }
/// #[derive(Component)]
/// struct Health(u32);
/// #[derive(Component)]
/// struct Strength(u32);
/// #[derive(Component)]
/// struct Defense(u32);
///
/// #[derive(Bundle)]
/// struct CombatBundle {
/// health: Health,
/// strength: Strength,
/// }
///
/// fn add_combat_stats_system(mut commands: Commands, player: Res<PlayerEntity>) {
/// commands
/// .entity(player.entity)
/// // You can insert individual components:
/// .insert(Defense(10))
/// // You can also insert pre-defined bundles of components:
/// .insert(CombatBundle {
/// health: Health(100),
/// strength: Strength(40),
/// })
/// // You can also insert tuples of components and bundles.
/// // This is equivalent to the calls above:
/// .insert((
/// Defense(10),
/// CombatBundle {
/// health: Health(100),
/// strength: Strength(40),
/// },
/// ));
/// }
/// # bevy_ecs::system::assert_is_system(add_combat_stats_system);
/// ```
#[track_caller]
pub fn insert(&mut self, bundle: impl Bundle) -> &mut Self {
self.queue(entity_command::insert(bundle, InsertMode::Replace))
}
/// Similar to [`Self::insert`] but will only insert if the predicate returns true.
/// This is useful for chaining method calls.
///
/// # Panics
///
/// The command will panic when applied if the associated entity does not exist.
///
/// To avoid a panic in this case, use the command [`Self::try_insert_if`] instead.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # #[derive(Resource)]
/// # struct PlayerEntity { entity: Entity }
/// # impl PlayerEntity { fn is_spectator(&self) -> bool { true } }
/// #[derive(Component)]
/// struct StillLoadingStats;
/// #[derive(Component)]
/// struct Health(u32);
///
/// fn add_health_system(mut commands: Commands, player: Res<PlayerEntity>) {
/// commands
/// .entity(player.entity)
/// .insert_if(Health(10), || !player.is_spectator())
/// .remove::<StillLoadingStats>();
/// }
/// # bevy_ecs::system::assert_is_system(add_health_system);
/// ```
#[track_caller]
pub fn insert_if<F>(&mut self, bundle: impl Bundle, condition: F) -> &mut Self
where
F: FnOnce() -> bool,
{
if condition() {
self.insert(bundle)
} else {
self
}
}
/// Adds a [`Bundle`] of components to the entity without overwriting.
///
/// This is the same as [`EntityCommands::insert`], but in case of duplicate
/// components will leave the old values instead of replacing them with new
/// ones.
///
/// See also [`entry`](Self::entry), which lets you modify a [`Component`] if it's present,
/// as well as initialize it with a default value.
///
/// # Panics
///
/// The command will panic when applied if the associated entity does not exist.
///
/// To avoid a panic in this case, use the command [`Self::try_insert_if_new`] instead.
#[track_caller]
pub fn insert_if_new(&mut self, bundle: impl Bundle) -> &mut Self {
self.queue(entity_command::insert(bundle, InsertMode::Keep))
}
/// Adds a [`Bundle`] of components to the entity without overwriting if the
/// predicate returns true.
///
/// This is the same as [`EntityCommands::insert_if`], but in case of duplicate
/// components will leave the old values instead of replacing them with new
/// ones.
///
/// # Panics
///
/// The command will panic when applied if the associated entity does not
/// exist.
///
/// To avoid a panic in this case, use the command [`Self::try_insert_if_new`]
/// instead.
#[track_caller]
pub fn insert_if_new_and<F>(&mut self, bundle: impl Bundle, condition: F) -> &mut Self
where
F: FnOnce() -> bool,
{
if condition() {
self.insert_if_new(bundle)
} else {
self
}
}
/// Adds a dynamic component to an entity.
///
/// See [`EntityWorldMut::insert_by_id`] for more information.
///
/// # Panics
///
/// The command will panic when applied if the associated entity does not exist.
///
/// To avoid a panic in this case, use the command [`Self::try_insert_by_id`] instead.
///
/// # Safety
///
/// - [`ComponentId`] must be from the same world as `self`.
/// - `T` must have the same layout as the one passed during `component_id` creation.
#[track_caller]
pub unsafe fn insert_by_id<T: Send + 'static>(
&mut self,
component_id: ComponentId,
value: T,
) -> &mut Self {
self.queue(
// SAFETY:
// - `ComponentId` safety is ensured by the caller.
// - `T` safety is ensured by the caller.
unsafe { entity_command::insert_by_id(component_id, value, InsertMode::Replace) },
)
}
/// Attempts to add a dynamic component to an entity.
///
/// See [`EntityWorldMut::insert_by_id`] for more information.
///
/// # Safety
///
/// - [`ComponentId`] must be from the same world as `self`.
/// - `T` must have the same layout as the one passed during `component_id` creation.
#[track_caller]
pub unsafe fn try_insert_by_id<T: Send + 'static>(
&mut self,
component_id: ComponentId,
value: T,
) -> &mut Self {
self.queue_handled(
// SAFETY:
// - `ComponentId` safety is ensured by the caller.
// - `T` safety is ensured by the caller.
unsafe { entity_command::insert_by_id(component_id, value, InsertMode::Replace) },
error_handler::silent(),
)
}
/// Tries to add a [`Bundle`] of components to the entity.
///
/// This will overwrite any previous value(s) of the same component type.
///
/// # Note
///
/// Unlike [`Self::insert`], this will not panic if the associated entity does not exist.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # #[derive(Resource)]
/// # struct PlayerEntity { entity: Entity }
/// #[derive(Component)]
/// struct Health(u32);
/// #[derive(Component)]
/// struct Strength(u32);
/// #[derive(Component)]
/// struct Defense(u32);
///
/// #[derive(Bundle)]
/// struct CombatBundle {
/// health: Health,
/// strength: Strength,
/// }
///
/// fn add_combat_stats_system(mut commands: Commands, player: Res<PlayerEntity>) {
/// commands.entity(player.entity)
/// // You can try_insert individual components:
/// .try_insert(Defense(10))
///
/// // You can also insert tuples of components:
/// .try_insert(CombatBundle {
/// health: Health(100),
/// strength: Strength(40),
/// });
///
/// // Suppose this occurs in a parallel adjacent system or process
/// commands.entity(player.entity)
/// .despawn();
///
/// commands.entity(player.entity)
/// // This will not panic nor will it add the component
/// .try_insert(Defense(5));
/// }
/// # bevy_ecs::system::assert_is_system(add_combat_stats_system);
/// ```
#[track_caller]
pub fn try_insert(&mut self, bundle: impl Bundle) -> &mut Self {
self.queue_handled(
entity_command::insert(bundle, InsertMode::Replace),
error_handler::silent(),
)
}
/// Similar to [`Self::try_insert`] but will only try to insert if the predicate returns true.
/// This is useful for chaining method calls.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # #[derive(Resource)]
/// # struct PlayerEntity { entity: Entity }
/// # impl PlayerEntity { fn is_spectator(&self) -> bool { true } }
/// #[derive(Component)]
/// struct StillLoadingStats;
/// #[derive(Component)]
/// struct Health(u32);
///
/// fn add_health_system(mut commands: Commands, player: Res<PlayerEntity>) {
/// commands.entity(player.entity)
/// .try_insert_if(Health(10), || !player.is_spectator())
/// .remove::<StillLoadingStats>();
///
/// commands.entity(player.entity)
/// // This will not panic nor will it add the component
/// .try_insert_if(Health(5), || !player.is_spectator());
/// }
/// # bevy_ecs::system::assert_is_system(add_health_system);
/// ```
#[track_caller]
pub fn try_insert_if<F>(&mut self, bundle: impl Bundle, condition: F) -> &mut Self
where
F: FnOnce() -> bool,
{
if condition() {
self.try_insert(bundle)
} else {
self
}
}
/// Tries to add a [`Bundle`] of components to the entity without overwriting if the
/// predicate returns true.
///
/// This is the same as [`EntityCommands::try_insert_if`], but in case of duplicate
/// components will leave the old values instead of replacing them with new
/// ones.
///
/// # Note
///
/// Unlike [`Self::insert_if_new_and`], this will not panic if the associated entity does
/// not exist.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # #[derive(Resource)]
/// # struct PlayerEntity { entity: Entity }
/// # impl PlayerEntity { fn is_spectator(&self) -> bool { true } }
/// #[derive(Component)]
/// struct StillLoadingStats;
/// #[derive(Component)]
/// struct Health(u32);
///
/// fn add_health_system(mut commands: Commands, player: Res<PlayerEntity>) {
/// commands.entity(player.entity)
/// .try_insert_if(Health(10), || player.is_spectator())
/// .remove::<StillLoadingStats>();
///
/// commands.entity(player.entity)
/// // This will not panic nor will it overwrite the component
/// .try_insert_if_new_and(Health(5), || player.is_spectator());
/// }
/// # bevy_ecs::system::assert_is_system(add_health_system);
/// ```
#[track_caller]
pub fn try_insert_if_new_and<F>(&mut self, bundle: impl Bundle, condition: F) -> &mut Self
where
F: FnOnce() -> bool,
{
if condition() {
self.try_insert_if_new(bundle)
} else {
self
}
}
/// Tries to add a [`Bundle`] of components to the entity without overwriting.
///
/// This is the same as [`EntityCommands::try_insert`], but in case of duplicate
/// components will leave the old values instead of replacing them with new
/// ones.
///
/// # Note
///
/// Unlike [`Self::insert_if_new`], this will not panic if the associated entity does not exist.
#[track_caller]
pub fn try_insert_if_new(&mut self, bundle: impl Bundle) -> &mut Self {
self.queue_handled(
entity_command::insert(bundle, InsertMode::Keep),
error_handler::silent(),
)
}
/// Removes a [`Bundle`] of components from the entity.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// #
/// # #[derive(Resource)]
/// # struct PlayerEntity { entity: Entity }
/// #[derive(Component)]
/// struct Health(u32);
/// #[derive(Component)]
/// struct Strength(u32);
/// #[derive(Component)]
/// struct Defense(u32);
///
/// #[derive(Bundle)]
/// struct CombatBundle {
/// health: Health,
/// strength: Strength,
/// }
///
/// fn remove_combat_stats_system(mut commands: Commands, player: Res<PlayerEntity>) {
/// commands
/// .entity(player.entity)
/// // You can remove individual components:
/// .remove::<Defense>()
/// // You can also remove pre-defined Bundles of components:
/// .remove::<CombatBundle>()
/// // You can also remove tuples of components and bundles.
/// // This is equivalent to the calls above:
/// .remove::<(Defense, CombatBundle)>();
/// }
/// # bevy_ecs::system::assert_is_system(remove_combat_stats_system);
/// ```
#[track_caller]
pub fn remove<T>(&mut self) -> &mut Self
where
T: Bundle,
{
self.queue_handled(entity_command::remove::<T>(), error_handler::warn())
}
/// Removes a [`Bundle`] of components from the entity.
///
/// # Note
///
/// Unlike [`Self::remove`], this will not panic if the associated entity does not exist.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// #
/// # #[derive(Resource)]
/// # struct PlayerEntity { entity: Entity }
/// #[derive(Component)]
/// struct Health(u32);
/// #[derive(Component)]
/// struct Strength(u32);
/// #[derive(Component)]
/// struct Defense(u32);
///
/// #[derive(Bundle)]
/// struct CombatBundle {
/// health: Health,
/// strength: Strength,
/// }
///
/// fn remove_combat_stats_system(mut commands: Commands, player: Res<PlayerEntity>) {
/// commands
/// .entity(player.entity)
/// // You can remove individual components:
/// .try_remove::<Defense>()
/// // You can also remove pre-defined Bundles of components:
/// .try_remove::<CombatBundle>()
/// // You can also remove tuples of components and bundles.
/// // This is equivalent to the calls above:
/// .try_remove::<(Defense, CombatBundle)>();
/// }
/// # bevy_ecs::system::assert_is_system(remove_combat_stats_system);
/// ```
pub fn try_remove<T>(&mut self) -> &mut Self
where
T: Bundle,
{
self.queue_handled(entity_command::remove::<T>(), error_handler::silent())
}
/// Removes all components in the [`Bundle`] components and remove all required components for each component in the [`Bundle`] from entity.
///
/// # Example
///
/// ```
/// use bevy_ecs::prelude::*;
///
/// #[derive(Component)]
/// #[require(B)]
/// struct A;
/// #[derive(Component, Default)]
/// struct B;
///
/// #[derive(Resource)]
/// struct PlayerEntity { entity: Entity }
///
/// fn remove_with_requires_system(mut commands: Commands, player: Res<PlayerEntity>) {
/// commands
/// .entity(player.entity)
/// // Remove both A and B components from the entity, because B is required by A
/// .remove_with_requires::<A>();
/// }
/// # bevy_ecs::system::assert_is_system(remove_with_requires_system);
/// ```
#[track_caller]
pub fn remove_with_requires<T: Bundle>(&mut self) -> &mut Self {
self.queue(entity_command::remove_with_requires::<T>())
}
/// Removes a dynamic [`Component`] from the entity if it exists.
///
/// # Panics
///
/// Panics if the provided [`ComponentId`] does not exist in the [`World`].
#[track_caller]
pub fn remove_by_id(&mut self, component_id: ComponentId) -> &mut Self {
self.queue(entity_command::remove_by_id(component_id))
}
/// Removes all components associated with the entity.
#[track_caller]
pub fn clear(&mut self) -> &mut Self {
self.queue(entity_command::clear())
}
/// Despawns the entity.
///
/// This will emit a warning if the entity does not exist.
///
/// See [`World::despawn`] for more details.
///
/// # Note
///
/// This will also despawn the entities in any [`RelationshipTarget`](crate::relationship::RelationshipTarget) that is configured
/// to despawn descendants. For example, this will recursively despawn [`Children`](crate::hierarchy::Children).
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// #
/// # #[derive(Resource)]
/// # struct CharacterToRemove { entity: Entity }
/// #
/// fn remove_character_system(
/// mut commands: Commands,
/// character_to_remove: Res<CharacterToRemove>
/// )
/// {
/// commands.entity(character_to_remove.entity).despawn();
/// }
/// # bevy_ecs::system::assert_is_system(remove_character_system);
/// ```
#[track_caller]
pub fn despawn(&mut self) {
self.queue_handled(entity_command::despawn(), error_handler::warn());
}
/// Despawns the provided entity and its descendants.
#[deprecated(
since = "0.16.0",
note = "Use entity.despawn(), which now automatically despawns recursively."
)]
pub fn despawn_recursive(&mut self) {
self.despawn();
}
/// Despawns the entity.
///
/// This will not emit a warning if the entity does not exist, essentially performing
/// the same function as [`Self::despawn`] without emitting warnings.
///
/// # Note
///
/// This will also despawn the entities in any [`RelationshipTarget`](crate::relationship::RelationshipTarget) that are configured
/// to despawn descendants. For example, this will recursively despawn [`Children`](crate::hierarchy::Children).
pub fn try_despawn(&mut self) {
self.queue_handled(entity_command::despawn(), error_handler::silent());
}
/// Pushes an [`EntityCommand`] to the queue, which will get executed for the current [`Entity`].
///
/// If the [`EntityCommand`] returns a [`Result`],
/// it will be handled using the [default error handler](error_handler::default).
///
/// To use a custom error handler, see [`EntityCommands::queue_handled`].
///
/// The command can be:
/// - A custom struct that implements [`EntityCommand`].
/// - A closure or function that matches the following signature:
/// - [`(EntityWorldMut)`](EntityWorldMut)
/// - [`(EntityWorldMut)`](EntityWorldMut) `->` [`Result`]
/// - A built-in command from the [`entity_command`] module.
///
/// # Examples
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # fn my_system(mut commands: Commands) {
/// commands
/// .spawn_empty()
/// // Closures with this signature implement `EntityCommand`.
/// .queue(|entity: EntityWorldMut| {
/// println!("Executed an EntityCommand for {}", entity.id());
/// });
/// # }
/// # bevy_ecs::system::assert_is_system(my_system);
/// ```
pub fn queue<C: EntityCommand<T> + CommandWithEntity<M>, T, M>(
&mut self,
command: C,
) -> &mut Self {
self.commands.queue(command.with_entity(self.entity));
self
}
/// Pushes an [`EntityCommand`] to the queue, which will get executed for the current [`Entity`].
///
/// If the [`EntityCommand`] returns a [`Result`],
/// the given `error_handler` will be used to handle error cases.
///
/// To implicitly use the default error handler, see [`EntityCommands::queue`].
///
/// The command can be:
/// - A custom struct that implements [`EntityCommand`].
/// - A closure or function that matches the following signature:
/// - [`(EntityWorldMut)`](EntityWorldMut)
/// - [`(EntityWorldMut)`](EntityWorldMut) `->` [`Result`]
/// - A built-in command from the [`entity_command`] module.
///
/// # Examples
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # use bevy_ecs::system::error_handler;
/// # fn my_system(mut commands: Commands) {
/// commands
/// .spawn_empty()
/// // Closures with this signature implement `EntityCommand`.
/// .queue_handled(
/// |entity: EntityWorldMut| -> Result {
/// let value: usize = "100".parse()?;
/// println!("Successfully parsed the value {} for entity {}", value, entity.id());
/// Ok(())
/// },
/// error_handler::warn()
/// );
/// # }
/// # bevy_ecs::system::assert_is_system(my_system);
/// ```
pub fn queue_handled<C: EntityCommand<T> + CommandWithEntity<M>, T, M>(
&mut self,
command: C,
error_handler: fn(&mut World, Error),
) -> &mut Self {
self.commands
.queue_handled(command.with_entity(self.entity), error_handler);
self
}
/// Removes all components except the given [`Bundle`] from the entity.
///
/// This can also be used to remove all the components from the entity by passing it an empty Bundle.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// #
/// # #[derive(Resource)]
/// # struct PlayerEntity { entity: Entity }
/// #[derive(Component)]
/// struct Health(u32);
/// #[derive(Component)]
/// struct Strength(u32);
/// #[derive(Component)]
/// struct Defense(u32);
///
/// #[derive(Bundle)]
/// struct CombatBundle {
/// health: Health,
/// strength: Strength,
/// }
///
/// fn remove_combat_stats_system(mut commands: Commands, player: Res<PlayerEntity>) {
/// commands
/// .entity(player.entity)
/// // You can retain a pre-defined Bundle of components,
/// // with this removing only the Defense component
/// .retain::<CombatBundle>()
/// // You can also retain only a single component
/// .retain::<Health>()
/// // And you can remove all the components by passing in an empty Bundle
/// .retain::<()>();
/// }
/// # bevy_ecs::system::assert_is_system(remove_combat_stats_system);
/// ```
#[track_caller]
pub fn retain<T>(&mut self) -> &mut Self
where
T: Bundle,
{
self.queue(entity_command::retain::<T>())
}
/// Logs the components of the entity at the info level.
///
/// # Panics
///
/// The command will panic when applied if the associated entity does not exist.
pub fn log_components(&mut self) -> &mut Self {
self.queue(entity_command::log_components())
}
/// Returns the underlying [`Commands`].
pub fn commands(&mut self) -> Commands {
self.commands.reborrow()
}
/// Returns a mutable reference to the underlying [`Commands`].
pub fn commands_mut(&mut self) -> &mut Commands<'a, 'a> {
&mut self.commands
}
/// Sends a [`Trigger`](crate::observer::Trigger) targeting the entity.
/// This will run any [`Observer`] of the given [`Event`] watching this entity.
#[track_caller]
pub fn trigger(&mut self, event: impl Event) -> &mut Self {
self.queue(entity_command::trigger(event))
}
/// Creates an [`Observer`] listening for events of type `E` targeting this entity.
pub fn observe<E: Event, B: Bundle, M>(
&mut self,
observer: impl IntoObserverSystem<E, B, M>,
) -> &mut Self {
self.queue(entity_command::observe(observer))
}
/// Clones parts of an entity (components, observers, etc.) onto another entity,
/// configured through [`EntityClonerBuilder`].
///
/// By default, the other entity will receive all the components of the original that implement
/// [`Clone`] or [`Reflect`](bevy_reflect::Reflect).
///
/// # Panics
///
/// The command will panic when applied if the target entity does not exist.
///
/// # Example
///
/// Configure through [`EntityClonerBuilder`] as follows:
/// ```
/// # use bevy_ecs::prelude::*;
///
/// #[derive(Component, Clone)]
/// struct ComponentA(u32);
/// #[derive(Component, Clone)]
/// struct ComponentB(u32);
///
/// fn example_system(mut commands: Commands) {
/// // Create an empty entity
/// let target = commands.spawn_empty().id();
///
/// // Create a new entity and keep its EntityCommands
/// let mut entity = commands.spawn((ComponentA(10), ComponentB(20)));
///
/// // Clone only ComponentA onto the target
/// entity.clone_with(target, |builder| {
/// builder.deny::<ComponentB>();
/// });
/// }
/// # bevy_ecs::system::assert_is_system(example_system);
/// ```
///
/// See [`EntityClonerBuilder`] for more options.
pub fn clone_with(
&mut self,
target: Entity,
config: impl FnOnce(&mut EntityClonerBuilder) + Send + Sync + 'static,
) -> &mut Self {
self.queue(entity_command::clone_with(target, config))
}
/// Spawns a clone of this entity and returns the [`EntityCommands`] of the clone.
///
/// The clone will receive all the components of the original that implement
/// [`Clone`] or [`Reflect`](bevy_reflect::Reflect).
///
/// To configure cloning behavior (such as only cloning certain components),
/// use [`EntityCommands::clone_and_spawn_with`].
///
/// # Note
///
/// If the original entity does not exist when this command is applied,
/// the returned entity will have no components.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
///
/// #[derive(Component, Clone)]
/// struct ComponentA(u32);
/// #[derive(Component, Clone)]
/// struct ComponentB(u32);
///
/// fn example_system(mut commands: Commands) {
/// // Create a new entity and keep its EntityCommands
/// let mut entity = commands.spawn((ComponentA(10), ComponentB(20)));
///
/// // Create a clone of the first entity
/// let mut entity_clone = entity.clone_and_spawn();
/// }
/// # bevy_ecs::system::assert_is_system(example_system);
pub fn clone_and_spawn(&mut self) -> EntityCommands<'_> {
self.clone_and_spawn_with(|_| {})
}
/// Spawns a clone of this entity and allows configuring cloning behavior
/// using [`EntityClonerBuilder`], returning the [`EntityCommands`] of the clone.
///
/// By default, the clone will receive all the components of the original that implement
/// [`Clone`] or [`Reflect`](bevy_reflect::Reflect).
///
/// To exclude specific components, use [`EntityClonerBuilder::deny`].
/// To only include specific components, use [`EntityClonerBuilder::deny_all`]
/// followed by [`EntityClonerBuilder::allow`].
///
/// See the methods on [`EntityClonerBuilder`] for more options.
///
/// # Note
///
/// If the original entity does not exist when this command is applied,
/// the returned entity will have no components.
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
///
/// #[derive(Component, Clone)]
/// struct ComponentA(u32);
/// #[derive(Component, Clone)]
/// struct ComponentB(u32);
///
/// fn example_system(mut commands: Commands) {
/// // Create a new entity and keep its EntityCommands
/// let mut entity = commands.spawn((ComponentA(10), ComponentB(20)));
///
/// // Create a clone of the first entity, but without ComponentB
/// let mut entity_clone = entity.clone_and_spawn_with(|builder| {
/// builder.deny::<ComponentB>();
/// });
/// }
/// # bevy_ecs::system::assert_is_system(example_system);
pub fn clone_and_spawn_with(
&mut self,
config: impl FnOnce(&mut EntityClonerBuilder) + Send + Sync + 'static,
) -> EntityCommands<'_> {
let entity_clone = self.commands().spawn_empty().id();
self.clone_with(entity_clone, config);
EntityCommands {
commands: self.commands_mut().reborrow(),
entity: entity_clone,
}
}
/// Clones the specified components of this entity and inserts them into another entity.
///
/// Components can only be cloned if they implement
/// [`Clone`] or [`Reflect`](bevy_reflect::Reflect).
///
/// # Panics
///
/// The command will panic when applied if the target entity does not exist.
pub fn clone_components<B: Bundle>(&mut self, target: Entity) -> &mut Self {
self.queue(entity_command::clone_components::<B>(target))
}
/// Clones the specified components of this entity and inserts them into another entity,
/// then removes the components from this entity.
///
/// Components can only be cloned if they implement
/// [`Clone`] or [`Reflect`](bevy_reflect::Reflect).
///
/// # Panics
///
/// The command will panic when applied if the target entity does not exist.
pub fn move_components<B: Bundle>(&mut self, target: Entity) -> &mut Self {
self.queue(entity_command::move_components::<B>(target))
}
}
/// A wrapper around [`EntityCommands`] with convenience methods for working with a specified component type.
pub struct EntityEntryCommands<'a, T> {
entity_commands: EntityCommands<'a>,
marker: PhantomData<T>,
}
impl<'a, T: Component<Mutability = Mutable>> EntityEntryCommands<'a, T> {
/// Modify the component `T` if it exists, using the function `modify`.
pub fn and_modify(&mut self, modify: impl FnOnce(Mut<T>) + Send + Sync + 'static) -> &mut Self {
self.entity_commands
.queue(move |mut entity: EntityWorldMut| {
if let Some(value) = entity.get_mut() {
modify(value);
}
});
self
}
}
impl<'a, T: Component> EntityEntryCommands<'a, T> {
/// [Insert](EntityCommands::insert) `default` into this entity, if `T` is not already present.
///
/// See also [`or_insert_with`](Self::or_insert_with).
///
/// # Panics
///
/// Panics if the entity does not exist.
/// See [`or_try_insert`](Self::or_try_insert) for a non-panicking version.
#[track_caller]
pub fn or_insert(&mut self, default: T) -> &mut Self {
self.entity_commands.insert_if_new(default);
self
}
/// [Insert](EntityCommands::insert) `default` into this entity, if `T` is not already present.
///
/// Unlike [`or_insert`](Self::or_insert), this will not panic if the entity does not exist.
///
/// See also [`or_insert_with`](Self::or_insert_with).
#[track_caller]
pub fn or_try_insert(&mut self, default: T) -> &mut Self {
self.entity_commands.try_insert_if_new(default);
self
}
/// [Insert](EntityCommands::insert) the value returned from `default` into this entity, if `T` is not already present.
///
/// See also [`or_insert`](Self::or_insert) and [`or_try_insert`](Self::or_try_insert).
///
/// # Panics
///
/// Panics if the entity does not exist.
/// See [`or_try_insert_with`](Self::or_try_insert_with) for a non-panicking version.
#[track_caller]
pub fn or_insert_with(&mut self, default: impl Fn() -> T) -> &mut Self {
self.or_insert(default())
}
/// [Insert](EntityCommands::insert) the value returned from `default` into this entity, if `T` is not already present.
///
/// Unlike [`or_insert_with`](Self::or_insert_with), this will not panic if the entity does not exist.
///
/// See also [`or_insert`](Self::or_insert) and [`or_try_insert`](Self::or_try_insert).
#[track_caller]
pub fn or_try_insert_with(&mut self, default: impl Fn() -> T) -> &mut Self {
self.or_try_insert(default())
}
/// [Insert](EntityCommands::insert) `T::default` into this entity, if `T` is not already present.
///
/// See also [`or_insert`](Self::or_insert) and [`or_from_world`](Self::or_from_world).
///
/// # Panics
///
/// Panics if the entity does not exist.
#[track_caller]
pub fn or_default(&mut self) -> &mut Self
where
T: Default,
{
self.or_insert(T::default())
}
/// [Insert](EntityCommands::insert) `T::from_world` into this entity, if `T` is not already present.
///
/// See also [`or_insert`](Self::or_insert) and [`or_default`](Self::or_default).
///
/// # Panics
///
/// Panics if the entity does not exist.
#[track_caller]
pub fn or_from_world(&mut self) -> &mut Self
where
T: FromWorld,
{
self.entity_commands
.queue(entity_command::insert_from_world::<T>(InsertMode::Keep));
self
}
/// Get the [`EntityCommands`] from which the [`EntityEntryCommands`] was initiated.
///
/// This allows you to continue chaining method calls after calling [`EntityCommands::entry`].
///
/// # Example
///
/// ```
/// # use bevy_ecs::prelude::*;
/// # #[derive(Resource)]
/// # struct PlayerEntity { entity: Entity }
/// #[derive(Component)]
/// struct Level(u32);
///
/// fn level_up_system(mut commands: Commands, player: Res<PlayerEntity>) {
/// commands
/// .entity(player.entity)
/// .entry::<Level>()
/// // Modify the component if it exists
/// .and_modify(|mut lvl| lvl.0 += 1)
/// // Otherwise insert a default value
/// .or_insert(Level(0))
/// // Return the EntityCommands for the entity
/// .entity()
/// // And continue chaining method calls
/// .insert(Name::new("Player"));
/// }
/// # bevy_ecs::system::assert_is_system(level_up_system);
/// ```
pub fn entity(&mut self) -> EntityCommands {
self.entity_commands.reborrow()
}
}
#[cfg(test)]
mod tests {
use crate::{
component::Component,
resource::Resource,
system::Commands,
world::{CommandQueue, FromWorld, World},
};
use alloc::{string::String, sync::Arc, vec, vec::Vec};
use core::{
any::TypeId,
sync::atomic::{AtomicUsize, Ordering},
};
#[expect(
dead_code,
reason = "This struct is used to test how `Drop` behavior works in regards to SparseSet storage, and as such is solely a wrapper around `DropCk` to make it use the SparseSet storage. Because of this, the inner field is intentionally never read."
)]
#[derive(Component)]
#[component(storage = "SparseSet")]
struct SparseDropCk(DropCk);
#[derive(Component)]
struct DropCk(Arc<AtomicUsize>);
impl DropCk {
fn new_pair() -> (Self, Arc<AtomicUsize>) {
let atomic = Arc::new(AtomicUsize::new(0));
(DropCk(atomic.clone()), atomic)
}
}
impl Drop for DropCk {
fn drop(&mut self) {
self.0.as_ref().fetch_add(1, Ordering::Relaxed);
}
}
#[derive(Component, Resource)]
struct W<T>(T);
fn simple_command(world: &mut World) {
world.spawn((W(0u32), W(42u64)));
}
impl FromWorld for W<String> {
fn from_world(world: &mut World) -> Self {
let v = world.resource::<W<usize>>();
Self("*".repeat(v.0))
}
}
#[test]
fn entity_commands_entry() {
let mut world = World::default();
let mut queue = CommandQueue::default();
let mut commands = Commands::new(&mut queue, &world);
let entity = commands.spawn_empty().id();
commands
.entity(entity)
.entry::<W<u32>>()
.and_modify(|_| unreachable!());
queue.apply(&mut world);
assert!(!world.entity(entity).contains::<W<u32>>());
let mut commands = Commands::new(&mut queue, &world);
commands
.entity(entity)
.entry::<W<u32>>()
.or_insert(W(0))
.and_modify(|mut val| {
val.0 = 21;
});
queue.apply(&mut world);
assert_eq!(21, world.get::<W<u32>>(entity).unwrap().0);
let mut commands = Commands::new(&mut queue, &world);
commands
.entity(entity)
.entry::<W<u64>>()
.and_modify(|_| unreachable!())
.or_insert(W(42));
queue.apply(&mut world);
assert_eq!(42, world.get::<W<u64>>(entity).unwrap().0);
world.insert_resource(W(5_usize));
let mut commands = Commands::new(&mut queue, &world);
commands.entity(entity).entry::<W<String>>().or_from_world();
queue.apply(&mut world);
assert_eq!("*****", &world.get::<W<String>>(entity).unwrap().0);
let mut commands = Commands::new(&mut queue, &world);
let id = commands.entity(entity).entry::<W<u64>>().entity().id();
queue.apply(&mut world);
assert_eq!(id, entity);
}
#[test]
fn commands() {
let mut world = World::default();
let mut command_queue = CommandQueue::default();
let entity = Commands::new(&mut command_queue, &world)
.spawn((W(1u32), W(2u64)))
.id();
command_queue.apply(&mut world);
assert_eq!(world.entities().len(), 1);
let results = world
.query::<(&W<u32>, &W<u64>)>()
.iter(&world)
.map(|(a, b)| (a.0, b.0))
.collect::<Vec<_>>();
assert_eq!(results, vec![(1u32, 2u64)]);
// test entity despawn
{
let mut commands = Commands::new(&mut command_queue, &world);
commands.entity(entity).despawn();
commands.entity(entity).despawn(); // double despawn shouldn't panic
}
command_queue.apply(&mut world);
let results2 = world
.query::<(&W<u32>, &W<u64>)>()
.iter(&world)
.map(|(a, b)| (a.0, b.0))
.collect::<Vec<_>>();
assert_eq!(results2, vec![]);
// test adding simple (FnOnce) commands
{
let mut commands = Commands::new(&mut command_queue, &world);
// set up a simple command using a closure that adds one additional entity
commands.queue(|world: &mut World| {
world.spawn((W(42u32), W(0u64)));
});
// set up a simple command using a function that adds one additional entity
commands.queue(simple_command);
}
command_queue.apply(&mut world);
let results3 = world
.query::<(&W<u32>, &W<u64>)>()
.iter(&world)
.map(|(a, b)| (a.0, b.0))
.collect::<Vec<_>>();
assert_eq!(results3, vec![(42u32, 0u64), (0u32, 42u64)]);
}
#[test]
fn insert_components() {
let mut world = World::default();
let mut command_queue1 = CommandQueue::default();
// insert components
let entity = Commands::new(&mut command_queue1, &world)
.spawn(())
.insert_if(W(1u8), || true)
.insert_if(W(2u8), || false)
.insert_if_new(W(1u16))
.insert_if_new(W(2u16))
.insert_if_new_and(W(1u32), || false)
.insert_if_new_and(W(2u32), || true)
.insert_if_new_and(W(3u32), || true)
.id();
command_queue1.apply(&mut world);
let results = world
.query::<(&W<u8>, &W<u16>, &W<u32>)>()
.iter(&world)
.map(|(a, b, c)| (a.0, b.0, c.0))
.collect::<Vec<_>>();
assert_eq!(results, vec![(1u8, 1u16, 2u32)]);
// try to insert components after despawning entity
// in another command queue
Commands::new(&mut command_queue1, &world)
.entity(entity)
.try_insert_if_new_and(W(1u64), || true);
let mut command_queue2 = CommandQueue::default();
Commands::new(&mut command_queue2, &world)
.entity(entity)
.despawn();
command_queue2.apply(&mut world);
command_queue1.apply(&mut world);
}
#[test]
fn remove_components() {
let mut world = World::default();
let mut command_queue = CommandQueue::default();
let (dense_dropck, dense_is_dropped) = DropCk::new_pair();
let (sparse_dropck, sparse_is_dropped) = DropCk::new_pair();
let sparse_dropck = SparseDropCk(sparse_dropck);
let entity = Commands::new(&mut command_queue, &world)
.spawn((W(1u32), W(2u64), dense_dropck, sparse_dropck))
.id();
command_queue.apply(&mut world);
let results_before = world
.query::<(&W<u32>, &W<u64>)>()
.iter(&world)
.map(|(a, b)| (a.0, b.0))
.collect::<Vec<_>>();
assert_eq!(results_before, vec![(1u32, 2u64)]);
// test component removal
Commands::new(&mut command_queue, &world)
.entity(entity)
.remove::<W<u32>>()
.remove::<(W<u32>, W<u64>, SparseDropCk, DropCk)>();
assert_eq!(dense_is_dropped.load(Ordering::Relaxed), 0);
assert_eq!(sparse_is_dropped.load(Ordering::Relaxed), 0);
command_queue.apply(&mut world);
assert_eq!(dense_is_dropped.load(Ordering::Relaxed), 1);
assert_eq!(sparse_is_dropped.load(Ordering::Relaxed), 1);
let results_after = world
.query::<(&W<u32>, &W<u64>)>()
.iter(&world)
.map(|(a, b)| (a.0, b.0))
.collect::<Vec<_>>();
assert_eq!(results_after, vec![]);
let results_after_u64 = world
.query::<&W<u64>>()
.iter(&world)
.map(|v| v.0)
.collect::<Vec<_>>();
assert_eq!(results_after_u64, vec![]);
}
#[test]
fn remove_components_by_id() {
let mut world = World::default();
let mut command_queue = CommandQueue::default();
let (dense_dropck, dense_is_dropped) = DropCk::new_pair();
let (sparse_dropck, sparse_is_dropped) = DropCk::new_pair();
let sparse_dropck = SparseDropCk(sparse_dropck);
let entity = Commands::new(&mut command_queue, &world)
.spawn((W(1u32), W(2u64), dense_dropck, sparse_dropck))
.id();
command_queue.apply(&mut world);
let results_before = world
.query::<(&W<u32>, &W<u64>)>()
.iter(&world)
.map(|(a, b)| (a.0, b.0))
.collect::<Vec<_>>();
assert_eq!(results_before, vec![(1u32, 2u64)]);
// test component removal
Commands::new(&mut command_queue, &world)
.entity(entity)
.remove_by_id(world.components().get_id(TypeId::of::<W<u32>>()).unwrap())
.remove_by_id(world.components().get_id(TypeId::of::<W<u64>>()).unwrap())
.remove_by_id(world.components().get_id(TypeId::of::<DropCk>()).unwrap())
.remove_by_id(
world
.components()
.get_id(TypeId::of::<SparseDropCk>())
.unwrap(),
);
assert_eq!(dense_is_dropped.load(Ordering::Relaxed), 0);
assert_eq!(sparse_is_dropped.load(Ordering::Relaxed), 0);
command_queue.apply(&mut world);
assert_eq!(dense_is_dropped.load(Ordering::Relaxed), 1);
assert_eq!(sparse_is_dropped.load(Ordering::Relaxed), 1);
let results_after = world
.query::<(&W<u32>, &W<u64>)>()
.iter(&world)
.map(|(a, b)| (a.0, b.0))
.collect::<Vec<_>>();
assert_eq!(results_after, vec![]);
let results_after_u64 = world
.query::<&W<u64>>()
.iter(&world)
.map(|v| v.0)
.collect::<Vec<_>>();
assert_eq!(results_after_u64, vec![]);
}
#[test]
fn remove_resources() {
let mut world = World::default();
let mut queue = CommandQueue::default();
{
let mut commands = Commands::new(&mut queue, &world);
commands.insert_resource(W(123i32));
commands.insert_resource(W(456.0f64));
}
queue.apply(&mut world);
assert!(world.contains_resource::<W<i32>>());
assert!(world.contains_resource::<W<f64>>());
{
let mut commands = Commands::new(&mut queue, &world);
// test resource removal
commands.remove_resource::<W<i32>>();
}
queue.apply(&mut world);
assert!(!world.contains_resource::<W<i32>>());
assert!(world.contains_resource::<W<f64>>());
}
#[test]
fn remove_component_with_required_components() {
#[derive(Component)]
#[require(Y)]
struct X;
#[derive(Component, Default)]
struct Y;
#[derive(Component)]
struct Z;
let mut world = World::default();
let mut queue = CommandQueue::default();
let e = {
let mut commands = Commands::new(&mut queue, &world);
commands.spawn((X, Z)).id()
};
queue.apply(&mut world);
assert!(world.get::<Y>(e).is_some());
assert!(world.get::<X>(e).is_some());
assert!(world.get::<Z>(e).is_some());
{
let mut commands = Commands::new(&mut queue, &world);
commands.entity(e).remove_with_requires::<X>();
}
queue.apply(&mut world);
assert!(world.get::<Y>(e).is_none());
assert!(world.get::<X>(e).is_none());
assert!(world.get::<Z>(e).is_some());
}
#[test]
fn unregister_system_cached_commands() {
let mut world = World::default();
let mut queue = CommandQueue::default();
fn nothing() {}
let resources = world.iter_resources().count();
let id = world.register_system_cached(nothing);
assert_eq!(world.iter_resources().count(), resources + 1);
assert!(world.get_entity(id.entity).is_ok());
let mut commands = Commands::new(&mut queue, &world);
commands.unregister_system_cached(nothing);
queue.apply(&mut world);
assert_eq!(world.iter_resources().count(), resources);
assert!(world.get_entity(id.entity).is_err());
}
fn is_send<T: Send>() {}
fn is_sync<T: Sync>() {}
#[test]
fn test_commands_are_send_and_sync() {
is_send::<Commands>();
is_sync::<Commands>();
}
#[test]
fn append() {
let mut world = World::default();
let mut queue_1 = CommandQueue::default();
{
let mut commands = Commands::new(&mut queue_1, &world);
commands.insert_resource(W(123i32));
}
let mut queue_2 = CommandQueue::default();
{
let mut commands = Commands::new(&mut queue_2, &world);
commands.insert_resource(W(456.0f64));
}
queue_1.append(&mut queue_2);
queue_1.apply(&mut world);
assert!(world.contains_resource::<W<i32>>());
assert!(world.contains_resource::<W<f64>>());
}
}
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