feat: implement TrackableFilter for suffix

This change updates the suffix filter to implement the TrackableFilter
interface. This provides the functionality for the user to track which
fields were updated by the suffix filter.

api/filters/suffix/suffix.go

@@ -18,9 +18,17 @@ type Filter struct {
 	Suffix string `json:"suffix,omitempty" yaml:"suffix,omitempty"`
 
 	FieldSpec types.FieldSpec `json:"fieldSpec,omitempty" yaml:"fieldSpec,omitempty"`
+
+	trackableSetter filtersutil.TrackableSetter
 }
 
 var _ kio.Filter = Filter{}
+var _ kio.TrackableFilter = &Filter{}
+
+// WithMutationTracker registers a callback which will be invoked each time a field is mutated
+func (f *Filter) WithMutationTracker(callback func(key, value, tag string, node *yaml.RNode)) {
+	f.trackableSetter.WithMutationTracker(callback)
+}
 
 func (f Filter) Filter(nodes []*yaml.RNode) ([]*yaml.RNode, error) {
 	return kio.FilterAll(yaml.FilterFunc(f.run)).Filter(nodes)
@@ -37,6 +45,6 @@ func (f Filter) run(node *yaml.RNode) (*yaml.RNode, error) {
 }
 
 func (f Filter) evaluateField(node *yaml.RNode) error {
-	return filtersutil.SetScalar(fmt.Sprintf(
+	return f.trackableSetter.SetScalar(fmt.Sprintf(
 		"%s%s", node.YNode().Value, f.Suffix))(node)
 }

api/filters/suffix/suffix_test.go

@@ -11,8 +11,11 @@ import (
 	"sigs.k8s.io/kustomize/api/filters/suffix"
 	filtertest_test "sigs.k8s.io/kustomize/api/testutils/filtertest"
 	"sigs.k8s.io/kustomize/api/types"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
 )
 
+var mutationTrackerStub = filtertest_test.MutationTrackerStub{}
+
 var tests = map[string]TestCase{
 	"suffix": {
 		input: `
@@ -83,17 +86,61 @@ a:
 			FieldSpec: types.FieldSpec{Path: "a/b/c"},
 		},
 	},
+
+	"mutation tracker": {
+		input: `
+apiVersion: example.com/v1
+kind: Foo
+metadata:
+  name: instance
+---
+apiVersion: example.com/v1
+kind: Bar
+metadata:
+  name: instance
+`,
+		expected: `
+apiVersion: example.com/v1
+kind: Foo
+metadata:
+  name: instance-foo
+---
+apiVersion: example.com/v1
+kind: Bar
+metadata:
+  name: instance-foo
+`,
+		filter: suffix.Filter{
+			Suffix:    "-foo",
+			FieldSpec: types.FieldSpec{Path: "metadata/name"},
+		},
+		mutationTracker: mutationTrackerStub.MutationTracker,
+		expectedSetValueArgs: []filtertest_test.SetValueArg{
+			{
+				Value:    "instance-foo",
+				NodePath: []string{"metadata", "name"},
+			},
+			{
+				Value:    "instance-foo",
+				NodePath: []string{"metadata", "name"},
+			},
+		},
+	},
 }
 
 type TestCase struct {
-	input    string
-	expected string
-	filter   suffix.Filter
+	input                string
+	expected             string
+	filter               suffix.Filter
+	mutationTracker      func(key, value, tag string, node *yaml.RNode)
+	expectedSetValueArgs []filtertest_test.SetValueArg
 }
 
 func TestFilter(t *testing.T) {
 	for name := range tests {
+		mutationTrackerStub.Reset()
 		test := tests[name]
+		test.filter.WithMutationTracker(test.mutationTracker)
 		t.Run(name, func(t *testing.T) {
 			if !assert.Equal(t,
 				strings.TrimSpace(test.expected),
@@ -101,6 +148,7 @@ func TestFilter(t *testing.T) {
 					filtertest_test.RunFilter(t, test.input, test.filter))) {
 				t.FailNow()
 			}
+			assert.Equal(t, test.expectedSetValueArgs, mutationTrackerStub.SetValueArgs())
 		})
 	}
 }