Prevent emitting custom events with components for the zero entity (#444)

Author: mlange-42

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## [[v0.6.4]](https://github.com/mlange-42/ark/compare/v0.6.3...v0.6.4)
+
+### Bugfixes
+
+- Prevents emitting custom events with components for the zero entity (#444)
+
 ## [[v0.6.3]](https://github.com/mlange-42/ark/compare/v0.6.2...v0.6.3)
 
 ### Other

benchmark/table/main.go

@@ -10,7 +10,7 @@ import (
 	"github.com/mlange-42/ark/benchmark"
 )
 
-const version = "v0.6.3"
+const version = "v0.6.4"
 const goVersion = "1.25.1"
 
 func main() {

ecs/events_test.go

@@ -112,6 +112,11 @@ func TestCustomEventErrors(t *testing.T) {
 			world.Event(OnCreateEntity)
 		})
 
+	expectPanicsWithValue(t, "can't emit event with components for the zero entity",
+		func() {
+			world.Event(CustomEvent).For(C[Position]()).Emit(Entity{})
+		})
+
 	expectPanicsWithValue(t, "entity does not have the required event components",
 		func() {
 			world.Event(CustomEvent).For(C[Position]()).Emit(e)

ecs/world_internal.go

@@ -573,6 +573,9 @@ func (w *World) emitEvent(e *Event, entity Entity) {
 func (w *World) emitEventSlowPath(e *Event, entity Entity) {
 	var mask *bitMask
 	if entity.IsZero() {
+		if !e.mask.IsZero() {
+			panic("can't emit event with components for the zero entity")
+		}
 		mask = &w.storage.archetypes[0].mask
 	} else {
 		if !w.Alive(entity) {