Additional tests around reusing the same bases and components

api/internal/target/kusttarget.go

@@ -158,6 +158,8 @@ func (kt *KustTarget) AccumulateTarget() (
 	return kt.accumulateTarget(accumulator.MakeEmptyAccumulator())
 }
 
+// ra should be empty when this KustTarget is a Kustomization, or the ra of the parent if this KustTarget is a Component
+// (or empty if the Component does not have a parent).
 func (kt *KustTarget) accumulateTarget(ra *accumulator.ResAccumulator) (
 	resRa *accumulator.ResAccumulator, err error) {
 	ra, err = kt.accumulateResources(ra, kt.kustomization.Resources)
@@ -324,10 +326,13 @@ func (kt *KustTarget) accumulateDirectory(
 	}
 
 	var subRa *accumulator.ResAccumulator
-	if subKt.kustomization.Kind == types.ComponentKind {
+	if isComponent {
+		// Components don't create a new accumulator: the kustomization directives are added to the current accumulator
 		subRa, err = subKt.accumulateTarget(ra)
 		ra = accumulator.MakeEmptyAccumulator()
 	} else {
+		// Child Kustomizations create a new accumulator which resolves their kustomization directives, which will later
+		// be merged into the current accumulator.
 		subRa, err = subKt.AccumulateTarget()
 	}
 	if err != nil {

api/krusty/component_test.go

@@ -463,7 +463,7 @@ configMapGenerator:
 	err := th.RunWithErr("/app/prod", th.MakeDefaultOptions())
 	if !strings.Contains(
 		err.Error(),
-		"apiVersion should be kustomize.config.k8s.io/v1alpha1") {
+		"apiVersion for Component should be kustomize.config.k8s.io/v1alpha1") {
 		t.Fatalf("unexpected error: %s", err)
 	}
 }

api/types/kustomization.go

@@ -158,7 +158,7 @@ func (k *Kustomization) EnforceFields() []string {
 		requiredVersion = ComponentVersion
 	}
 	if k.APIVersion != "" && k.APIVersion != requiredVersion {
-		errs = append(errs, "apiVersion should be "+requiredVersion)
+		errs = append(errs, "apiVersion for "+k.Kind+" should be "+requiredVersion)
 	}
 	return errs
 }