Fix: Do not extend layouts of inactive archetypes

CHANGELOG.md

@@ -1,4 +1,4 @@
-## [[unpublished]](https://github.com/mlange-42/arche/compare/v0.11.0...main)
+## [[v0.12.0]](https://github.com/mlange-42/arche/compare/v0.11.0...v0.12.0)
 
 ### Features
 
@@ -12,6 +12,10 @@
 
 * Re-arrange struct fields to save memory in a few places (#413)
 
+### Bugfixes
+
+* Fix crash caused by extending layouts of an inactive archetype (#416, reported in #415)
+
 ### First-time contributors
 
 * [delaneyj](https://github.com/delaneyj)

ecs/archetype_node.go

@@ -136,7 +136,7 @@ func (a *archNode) CreateArchetype(layouts uint8, target Entity) *archetype {
 }
 
 func (a *archNode) ExtendArchetypeLayouts(count uint8) {
-	if !a.HasRelation {
+	if a.IsActive && !a.HasRelation {
 		a.archetype.ExtendLayouts(count)
 		return
 	}

ecs/types_test.go

@@ -60,6 +60,7 @@ type testStruct13 struct{ val int32 }
 type testStruct14 struct{ val int32 }
 type testStruct15 struct{ val int32 }
 type testStruct16 struct{ val int32 }
+type testStruct17 struct{ val int32 }
 
 type withSlice struct {
 	Slice []int

ecs/world_test.go

@@ -1878,6 +1878,34 @@ func TestWorldExtendLayouts(t *testing.T) {
 	}
 }
 
+func TestWorldExtendLayouts2(t *testing.T) {
+	w := NewWorld()
+
+	id1 := ComponentID[testStruct0](&w)
+	id2 := ComponentID[testStruct1](&w)
+	_ = ComponentID[testStruct2](&w)
+	_ = ComponentID[testStruct3](&w)
+	_ = ComponentID[testStruct4](&w)
+	_ = ComponentID[testStruct5](&w)
+	_ = ComponentID[testStruct6](&w)
+	_ = ComponentID[testStruct7](&w)
+	_ = ComponentID[testStruct8](&w)
+	_ = ComponentID[testStruct9](&w)
+	_ = ComponentID[testStruct10](&w)
+	_ = ComponentID[testStruct11](&w)
+	_ = ComponentID[testStruct12](&w)
+	_ = ComponentID[testStruct13](&w)
+	_ = ComponentID[testStruct14](&w)
+
+	_ = w.NewEntity(id1, id2)
+
+	_ = ComponentID[testStruct15](&w)
+	_ = ComponentID[testStruct16](&w)
+	id17 := ComponentID[testStruct17](&w)
+
+	_ = w.NewEntity(id17)
+}
+
 func TestWorldPointerStressTest(t *testing.T) {
 	w := NewWorld()