feat: use rangefunc for iterators

Give rangefunc a try.

Signed-off-by: Utku Ozdemir <utku.ozdemir@siderolabs.com>

pkg/controller/conformance/controllers.go

@@ -75,9 +75,7 @@ func (ctrl *IntToStrController) Run(ctx context.Context, r controller.Runtime, _
 			return fmt.Errorf("error listing objects: %w", err)
 		}
 
-		for iter := intList.Iterator(); iter.Next(); {
-			intRes := iter.Value()
-
+		for intRes := range intList.All() {
 			strRes := NewStrResource(ctrl.TargetNamespace, intRes.Metadata().ID(), "")
 
 			switch intRes.Metadata().Phase() {
@@ -183,9 +181,7 @@ func (ctrl *StrToSentenceController) Run(ctx context.Context, r controller.Runti
 			return fmt.Errorf("error listing objects: %w", err)
 		}
 
-		for iter := strList.Iterator(); iter.Next(); {
-			strRes := iter.Value()
-
+		for strRes := range strList.All() {
 			sentenceRes := NewSentenceResource(ctrl.TargetNamespace, strRes.Metadata().ID(), "")
 
 			switch strRes.Metadata().Phase() {
@@ -287,8 +283,8 @@ func (ctrl *SumController) Run(ctx context.Context, r controller.Runtime, _ *zap
 
 		var sum int
 
-		for iter := intList.Iterator(); iter.Next(); {
-			sum += iter.Value().Value()
+		for val := range intList.All() {
+			sum += val.Value()
 		}
 
 		if err = safe.WriterModify(ctx, r, NewIntResource(ctrl.TargetNamespace, ctrl.TargetID, 0), func(r *IntResource) error {
@@ -409,9 +405,7 @@ func (ctrl *IntDoublerController) Run(ctx context.Context, r controller.Runtime,
 			return fmt.Errorf("error listing objects: %w", err)
 		}
 
-		for iter := intList.Iterator(); iter.Next(); {
-			intRes := iter.Value()
-
+		for intRes := range intList.All() {
 			outRes := NewIntResource(ctrl.TargetNamespace, intRes.Metadata().ID(), 0)
 
 			if err = safe.WriterModify(ctx, r, outRes, func(r *IntResource) error {
@@ -480,9 +474,7 @@ func (ctrl *ModifyWithResultController) Run(ctx context.Context, r controller.Ru
 			return fmt.Errorf("error listing objects: %w", err)
 		}
 
-		for iter := strList.Iterator(); iter.Next(); {
-			strRes := iter.Value()
-
+		for strRes := range strList.All() {
 			id := strRes.Metadata().ID() + "-out"
 			val := strRes.Value() + "-modified"
 
@@ -575,9 +567,7 @@ func (ctrl *MetricsController) Run(ctx context.Context, r controller.Runtime, _
 			return fmt.Errorf("error listing objects: %w", err)
 		}
 
-		for iter := intList.Iterator(); iter.Next(); {
-			intRes := iter.Value()
-
+		for intRes := range intList.All() {
 			if intRes.Value() == 42 {
 				return fmt.Errorf("magic number caused controller to crash")
 			}

pkg/controller/generic/cleanup/cleanup.go

@@ -105,8 +105,8 @@ func (ctrl *Controller[I]) Run(ctx context.Context, r controller.Runtime, logger
 
 		var multiErr error
 
-		for iter := inputList.Iterator(); iter.Next(); {
-			err := ctrl.processInput(ctx, r, logger, iter.Value())
+		for val := range inputList.All() {
+			err := ctrl.processInput(ctx, r, logger, val)
 			if err != nil {
 				multiErr = multierror.Append(multiErr, err)
 			}
@@ -308,9 +308,7 @@ func RemoveOutputs[O generic.ResourceWithRD, I generic.ResourceWithRD](
 
 			var inTearDown int
 
-			for iter := list.Iterator(); iter.Next(); {
-				out := iter.Value()
-
+			for out := range list.All() {
 				owner := out.Metadata().Owner()
 
 				var allowedOwner bool

pkg/controller/generic/transform/controller.go

@@ -291,9 +291,7 @@ func (ctrl *Controller[Input, Output]) processInputs(
 	}
 
 	// create outputs based on inputs
-	for iter := inputItems.Iterator(); iter.Next(); {
-		in := iter.Value()
-
+	for in := range inputItems.All() {
 		mappedOut, present := ctrl.mapFunc(in).Get()
 		if !present {
 			// skip this resource
@@ -399,9 +397,7 @@ func (ctrl *Controller[Input, Output]) cleanupOutputs(
 		return fmt.Errorf("error listing output resources: %w", err)
 	}
 
-	for iter := outputItems.Iterator(); iter.Next(); {
-		out := iter.Value()
-
+	for out := range outputItems.All() {
 		// output not owned by this controller, skip it
 		if out.Metadata().Owner() != ctrl.Name() {
 			delete(runState.removeInputFinalizers, out.Metadata().ID())

pkg/safe/state.go

@@ -7,10 +7,11 @@ package safe
 import (
 	"context"
 	"fmt"
+	"iter" //nolint:gci
 	"slices"
 
 	"github.com/siderolabs/gen/channel"
-	"github.com/siderolabs/gen/xslices"
+	"github.com/siderolabs/gen/xslices" //nolint:gci
 
 	"github.com/cosi-project/runtime/pkg/controller/generic"
 	"github.com/cosi-project/runtime/pkg/resource"
@@ -294,10 +295,23 @@ func (l *List[T]) Find(fn func(T) bool) (T, bool) {
 func (l *List[T]) Swap(i, j int) { l.list.Items[i], l.list.Items[j] = l.list.Items[j], l.list.Items[i] }
 
 // Iterator returns a new iterator over the list.
+//
+// Deprecated: use [List.All] instead.
 func (l *List[T]) Iterator() ListIterator[T] {
 	return ListIterator[T]{pos: 0, list: *l}
 }
 
+// All returns a new rangefunc iterator over the list.
+func (l *List[T]) All() iter.Seq[T] {
+	return func(yield func(T) bool) {
+		for i := range l.list.Items {
+			if !yield(l.Get(i)) {
+				return
+			}
+		}
+	}
+}
+
 // ListIterator is a generic iterator over resource.Resource slice.
 type ListIterator[T any] struct {
 	list List[T]
@@ -306,7 +320,7 @@ type ListIterator[T any] struct {
 
 // IteratorFromList returns a new iterator over the given list.
 //
-// Deprecated: use [List.Iterator] instead.
+// Deprecated: use [List.All] instead.
 func IteratorFromList[T any](list List[T]) ListIterator[T] {
 	return ListIterator[T]{pos: 0, list: list}
 }