Skip to content

Mention in .add_observer() docs that first parameter must be a Trigger #19315

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 3 commits into
base: main
Choose a base branch
from
Open

Mention in .add_observer() docs that first parameter must be a Trigger #19315

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
05ce253
Mention in .add_observer() docs that first parameter must be a Trigger
theotherphil May 20, 2025
514f097
Fix intra-doc link
theotherphil May 20, 2025
0b0ee45
Merge branch 'main' into triggerdoc
theotherphil May 20, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 3 additions & 1 deletion crates/bevy_app/src/app.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1306,6 +1306,8 @@ impl App {

/// Spawns an [`Observer`] entity, which will watch for and respond to the given event.
///
/// `observer` can be any system whose first parameter is a [`Trigger`].
///
/// # Examples
///
/// ```rust
Expand All @@ -1326,7 +1328,7 @@ impl App {
/// # #[derive(Component)]
/// # struct Friend;
/// #
/// // An observer system can be any system where the first parameter is a trigger
///
/// app.add_observer(|trigger: Trigger<Party>, friends: Query<Entity, With<Friend>>, mut commands: Commands| {
/// if trigger.event().friends_allowed {
/// for friend in friends.iter() {
Expand Down
2 changes: 2 additions & 0 deletions crates/bevy_ecs/src/observer/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -536,6 +536,8 @@ impl World {
/// Spawns a "global" [`Observer`] which will watch for the given event.
/// Returns its [`Entity`] as a [`EntityWorldMut`].
///
/// `system` can be any system whose first parameter is a [`Trigger`].
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Nit: Maybe we want to rename the parameter here to observer to match the rest of the codebase?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This context maybe feels slightly different from the other two? I have no particular preference though - happy to change if you'd prefer.

///
/// **Calling [`observe`](EntityWorldMut::observe) on the returned
/// [`EntityWorldMut`] will observe the observer itself, which you very
/// likely do not want.**
Expand Down
4 changes: 4 additions & 0 deletions crates/bevy_ecs/src/system/commands/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1068,13 +1068,17 @@ impl<'w, 's> Commands<'w, 's> {
/// Spawns an [`Observer`] and returns the [`EntityCommands`] associated
/// with the entity that stores the observer.
///
/// `observer` can be any system whose first parameter is a [`Trigger`].
///
/// **Calling [`observe`](EntityCommands::observe) on the returned
/// [`EntityCommands`] will observe the observer itself, which you very
/// likely do not want.**
///
/// # Panics
///
/// Panics if the given system is an exclusive system.
///
/// [`Trigger`]: crate::observer::Trigger
pub fn add_observer<E: Event, B: Bundle, M>(
&mut self,
observer: impl IntoObserverSystem<E, B, M>,
Expand Down