Prefer nil empty slices

Signed-off-by: David Gageot <david.gageot@docker.com>

pkg/init/cmd/rc.init/main.go

@@ -80,7 +80,7 @@ func mkdir(path string, perm os.FileMode) {
 
 // list of all enabled cgroups
 func cgroupList() []string {
-	list := []string{}
+	var list []string
 	f, err := os.Open("/proc/cgroups")
 	if err != nil {
 		log.Printf("cannot open /proc/cgroups: %v", err)
@@ -125,7 +125,7 @@ func read(path string) string {
 
 // read a directory
 func readdir(path string) []string {
-	names := []string{}
+	var names []string
 	files, err := os.ReadDir(path)
 	if err != nil {
 		log.Printf("cannot read directory %s: %v", path, err)

pkg/init/cmd/service/system_init.go

@@ -85,7 +85,7 @@ func systemInitCmd(ctx context.Context, args []string) {
 	_ = os.Remove(*sock)
 
 	// look for containerd options
-	ctrdArgs := []string{}
+	var ctrdArgs []string
 	var (
 		stderr io.Writer = os.Stderr
 		stdout io.Writer = os.Stdout

pkg/metadata/provider_cdrom.go

@@ -48,7 +48,7 @@ func ListCDROMs() []Provider {
 	cdroms = append(cidevs, cdroms...)
 	cdroms = uniqueString(cdroms)
 	log.Debugf("unique devices to be checked: %v", cdroms)
-	providers := []Provider{}
+	var providers []Provider
 	for _, device := range cdroms {
 		providers = append(providers, NewCDROM(device))
 	}
@@ -65,7 +65,7 @@ func FindCIs() []string {
 		// Glob can only error on invalid pattern
 		panic(fmt.Sprintf("Invalid glob pattern: %s", blockDevs))
 	}
-	foundDevices := []string{}
+	var foundDevices []string
 	for _, device := range devs {
 		// get the base device name
 		dev := filepath.Base(device)

pkg/mount/mountie.go

@@ -197,7 +197,7 @@ func makeDevLinks() error {
 
 // return a list of all available drives
 func findDrives() []string {
-	driveKeys := []string{}
+	var driveKeys []string
 	ignoreExp := regexp.MustCompile(`^loop.*$|^nbd.*$|^[a-z]+[0-9]+$`)
 	devs, _ := ioutil.ReadDir("/dev")
 	for _, d := range devs {