Use any instead of interface{}

The keyword is available since Go 1.18 (see
https://pkg.go.dev/builtin#any).

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

libcontainer/configs/config.go

@@ -503,7 +503,7 @@ func (hooks *Hooks) MarshalJSON() ([]byte, error) {
 		return serializableHooks
 	}
 
-	return json.Marshal(map[string]interface{}{
+	return json.Marshal(map[string]any{
 		"prestart":        serialize((*hooks)[Prestart]),
 		"createRuntime":   serialize((*hooks)[CreateRuntime]),
 		"createContainer": serialize((*hooks)[CreateContainer]),

libcontainer/factory_linux_test.go

@@ -81,7 +81,7 @@ func TestFactoryLoadContainer(t *testing.T) {
 	}
 }
 
-func marshal(path string, v interface{}) error {
+func marshal(path string, v any) error {
 	f, err := os.Create(path)
 	if err != nil {
 		return err

libcontainer/specconv/spec_linux_test.go

@@ -676,7 +676,7 @@ func TestInitSystemdProps(t *testing.T) {
 	type expT struct {
 		isErr bool
 		name  string
-		value interface{}
+		value any
 	}
 
 	testCases := []struct {

libcontainer/state_linux_test.go

@@ -24,7 +24,7 @@ func TestStateStatus(t *testing.T) {
 }
 
 func testTransitions(t *testing.T, initialState containerState, valid []containerState) {
-	validMap := map[reflect.Type]interface{}{}
+	validMap := map[reflect.Type]any{}
 	for _, validState := range valid {
 		validMap[reflect.TypeOf(validState)] = nil
 		t.Run(validState.status().String(), func(t *testing.T) {

libcontainer/sync.go

@@ -113,7 +113,7 @@ func writeSync(pipe *syncSocket, sync syncType) error {
 	return doWriteSync(pipe, syncT{Type: sync})
 }
 
-func writeSyncArg(pipe *syncSocket, sync syncType, arg interface{}) error {
+func writeSyncArg(pipe *syncSocket, sync syncType, arg any) error {
 	argJSON, err := json.Marshal(arg)
 	if err != nil {
 		return fmt.Errorf("writing sync %v: marshal argument failed: %w", sync, err)

libcontainer/utils/utils.go

@@ -27,7 +27,7 @@ func ExitStatus(status unix.WaitStatus) int {
 // without a trailing newline. This is used instead of json.Encoder because
 // there might be a problem in json decoder in some cases, see:
 // https://github.com/docker/docker/issues/14203#issuecomment-174177790
-func WriteJSON(w io.Writer, v interface{}) error {
+func WriteJSON(w io.Writer, v any) error {
 	data, err := json.Marshal(v)
 	if err != nil {
 		return err

tty.go

@@ -44,7 +44,7 @@ func setupProcessPipes(p *libcontainer.Process, rootuid, rootgid int) (*tty, err
 		},
 	}
 	// add the process's io to the post start closers if they support close
-	for _, cc := range []interface{}{
+	for _, cc := range []any{
 		p.Stdin,
 		p.Stdout,
 		p.Stderr,

types/events.go

@@ -7,9 +7,9 @@ import (
 
 // Event struct for encoding the event data to json.
 type Event struct {
-	Type string      `json:"type"`
-	ID   string      `json:"id"`
-	Data interface{} `json:"data,omitempty"`
+	Type string `json:"type"`
+	ID   string `json:"id"`
+	Data any    `json:"data,omitempty"`
 }
 
 // Stats is the runc specific stats structure for stability when encoding and decoding stats.