modernize: Prefer strings.SplitSeq instead of Split

Avoids extra allocations. Added in Go 1.24.

Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>

daemon/container_operations.go

@@ -545,7 +545,7 @@ func validateEndpointSettings(nw *libnetwork.Network, nwName string, epConfig *n
 	}
 
 	if sysctls, ok := epConfig.DriverOpts[netlabel.EndpointSysctls]; ok {
-		for _, sysctl := range strings.Split(sysctls, ",") {
+		for sysctl := range strings.SplitSeq(sysctls, ",") {
 			scname := strings.SplitN(sysctl, ".", 5)
 			// Allow "ifname" as well as "IFNAME", because the CLI converts to lower case.
 			if len(scname) != 5 ||

daemon/containerd/image_push.go

@@ -404,7 +404,7 @@ func extractDistributionSources(labels map[string]string) []distributionSource {
 	// if yes, read it as source
 	for k, v := range labels {
 		if reg := strings.TrimPrefix(k, containerdlabels.LabelDistributionSource); reg != k {
-			for _, repo := range strings.Split(v, ",") {
+			for repo := range strings.SplitSeq(v, ",") {
 				ref, err := reference.ParseNamed(reg + "/" + repo)
 				if err != nil {
 					continue

daemon/events/testutils/testutils.go

@@ -56,7 +56,7 @@ func Scan(text string) (*events.Message, error) {
 	}
 
 	attrs := make(map[string]string)
-	for _, a := range strings.Split(md["attributes"], ", ") {
+	for a := range strings.SplitSeq(md["attributes"], ", ") {
 		k, v, _ := strings.Cut(a, "=")
 		attrs[k] = v
 	}

daemon/graphdriver/fuse-overlayfs/fuseoverlayfs.go

@@ -264,7 +264,7 @@ func (d *Driver) getLowerDirs(id string) ([]string, error) {
 	var lowersArray []string
 	lowers, err := os.ReadFile(path.Join(d.dir(id), lowerFile))
 	if err == nil {
-		for _, s := range strings.Split(string(lowers), ":") {
+		for s := range strings.SplitSeq(string(lowers), ":") {
 			lp, err := os.Readlink(path.Join(d.home, s))
 			if err != nil {
 				return nil, err

daemon/graphdriver/overlay2/overlay.go

@@ -469,7 +469,7 @@ func (d *Driver) getLowerDirs(id string) ([]string, error) {
 	var lowersArray []string
 	lowers, err := os.ReadFile(path.Join(d.dir(id), lowerFile))
 	if err == nil {
-		for _, s := range strings.Split(string(lowers), ":") {
+		for s := range strings.SplitSeq(string(lowers), ":") {
 			lp, err := os.Readlink(path.Join(d.home, s))
 			if err != nil {
 				return nil, err

daemon/info_unix.go

@@ -361,8 +361,8 @@ func parseInitVersion(v string) (version string, commit string, _ error) {
 //	commit: 69663f0bd4b60df09991c08812a60108003fa340
 //	spec: 1.0.0
 func parseRuntimeVersion(v string) (runtime, version, commit string, _ error) {
-	lines := strings.Split(strings.TrimSpace(v), "\n")
-	for _, line := range lines {
+	lines := strings.SplitSeq(strings.TrimSpace(v), "\n")
+	for line := range lines {
 		if strings.Contains(line, "version") {
 			s := strings.Split(line, "version")
 			runtime = strings.TrimSpace(s[0])

daemon/internal/builder-next/exporter/mobyexporter/export.go

@@ -60,7 +60,7 @@ func (e *imageExporter) Resolve(ctx context.Context, id int, attrs map[string]st
 	for k, v := range attrs {
 		switch exptypes.ImageExporterOptKey(k) {
 		case exptypes.OptKeyName:
-			for _, v := range strings.Split(v, ",") {
+			for v := range strings.SplitSeq(v, ",") {
 				ref, err := reference.ParseNormalizedNamed(v)
 				if err != nil {
 					return nil, err

daemon/internal/builder-next/exporter/wrapper.go

@@ -100,7 +100,7 @@ func (i *imageExporterInstanceWrapper) processNamedCallback(ctx context.Context,
 		return
 	}
 
-	for _, name := range strings.Split(imageName, ",") {
+	for name := range strings.SplitSeq(imageName, ",") {
 		ref, err := reference.ParseNormalizedNamed(name)
 		if err != nil {
 			// Shouldn't happen, but log if it does and continue.

daemon/internal/distribution/manifest.go

@@ -86,8 +86,8 @@ func appendDistributionSourceLabel(originLabel, repo string) string {
 }
 
 func hasDistributionSource(label, repo string) bool {
-	sources := strings.Split(label, ",")
-	for _, s := range sources {
+	sources := strings.SplitSeq(label, ",")
+	for s := range sources {
 		if s == repo {
 			return true
 		}

daemon/logger/loginfo.go

@@ -31,7 +31,7 @@ func (info *Info) ExtraAttributes(keyMod func(string) string) (map[string]string
 	extra := make(map[string]string)
 
 	if labels, ok := info.Config["labels"]; ok && labels != "" {
-		for _, l := range strings.Split(labels, ",") {
+		for l := range strings.SplitSeq(labels, ",") {
 			if v, ok := info.ContainerLabels[l]; ok {
 				if keyMod != nil {
 					l = keyMod(l)
@@ -69,7 +69,7 @@ func (info *Info) ExtraAttributes(keyMod func(string) string) (map[string]string
 	}
 
 	if env, ok := info.Config["env"]; ok && env != "" {
-		for _, l := range strings.Split(env, ",") {
+		for l := range strings.SplitSeq(env, ",") {
 			if v, ok := envMapping[l]; ok {
 				if keyMod != nil {
 					l = keyMod(l)

daemon/oci_linux.go

@@ -408,7 +408,7 @@ const (
 // hasMountInfoOption checks if any of the passed any of the given option values
 // are set in the passed in option string.
 func hasMountInfoOption(opts string, vals ...string) bool {
-	for _, opt := range strings.Split(opts, " ") {
+	for opt := range strings.SplitSeq(opts, " ") {
 		for _, val := range vals {
 			if strings.HasPrefix(opt, val) {
 				return true

daemon/volume/local/local.go

@@ -419,7 +419,7 @@ func (v *localVolume) LiveRestoreVolume(ctx context.Context, _ string) error {
 
 // getAddress finds out address/hostname from options
 func getAddress(opts string) string {
-	for _, opt := range strings.Split(opts, ",") {
+	for opt := range strings.SplitSeq(opts, ",") {
 		if strings.HasPrefix(opt, "addr=") {
 			return strings.TrimPrefix(opt, "addr=")
 		}
@@ -429,7 +429,7 @@ func getAddress(opts string) string {
 
 // getPassword finds out a password from options
 func getPassword(opts string) string {
-	for _, opt := range strings.Split(opts, ",") {
+	for opt := range strings.SplitSeq(opts, ",") {
 		if strings.HasPrefix(opt, "password=") {
 			return strings.TrimPrefix(opt, "password=")
 		}

daemon/volume/mounts/linux_parser.go

@@ -174,7 +174,7 @@ var linuxPropagationModes = map[mount.Propagation]bool{
 const linuxDefaultPropagationMode = mount.PropagationRPrivate
 
 func linuxGetPropagation(mode string) mount.Propagation {
-	for _, o := range strings.Split(mode, ",") {
+	for o := range strings.SplitSeq(mode, ",") {
 		prop := mount.Propagation(o)
 		if linuxPropagationModes[prop] {
 			return prop
@@ -184,7 +184,7 @@ func linuxGetPropagation(mode string) mount.Propagation {
 }
 
 func linuxHasPropagation(mode string) bool {
-	for _, o := range strings.Split(mode, ",") {
+	for o := range strings.SplitSeq(mode, ",") {
 		if linuxPropagationModes[mount.Propagation(o)] {
 			return true
 		}
@@ -203,7 +203,7 @@ func linuxValidMountMode(mode string) bool {
 	copyModeCount := 0
 	consistencyModeCount := 0
 
-	for _, o := range strings.Split(mode, ",") {
+	for o := range strings.SplitSeq(mode, ",") {
 		switch {
 		case rwModes[o]:
 			rwModeCount++
@@ -256,7 +256,7 @@ func (p *linuxParser) ReadWrite(mode string) bool {
 		return false
 	}
 
-	for _, o := range strings.Split(mode, ",") {
+	for o := range strings.SplitSeq(mode, ",") {
 		if o == "ro" {
 			return false
 		}

daemon/volume/mounts/volume_copy.go

@@ -14,7 +14,7 @@ func copyModeExists(mode string) bool {
 
 // GetCopyMode gets the copy mode from the mode string for mounts
 func getCopyMode(mode string, def bool) (bool, bool) {
-	for _, o := range strings.Split(mode, ",") {
+	for o := range strings.SplitSeq(mode, ",") {
 		if isEnabled, exists := copyModes[o]; exists {
 			return isEnabled, true
 		}

integration-cli/docker_api_build_test.go

@@ -569,7 +569,7 @@ type buildLine struct {
 
 func getImageIDsFromBuild(t *testing.T, output []byte) []string {
 	var ids []string
-	for _, line := range bytes.Split(output, []byte("\n")) {
+	for line := range bytes.SplitSeq(output, []byte("\n")) {
 		if len(line) == 0 {
 			continue
 		}

integration-cli/docker_cli_images_test.go

@@ -199,8 +199,8 @@ func (s *DockerCLIImagesSuite) TestImagesFilterSinceAndBefore(c *testing.T) {
 
 func getImageIDs(out string) []string {
 	var actual []string
-	imgs := strings.Split(out, "\n")
-	for _, l := range imgs {
+	imgs := strings.SplitSeq(out, "\n")
+	for l := range imgs {
 		imgTag, imgDigest, _ := strings.Cut(l, "\t")
 		if strings.HasPrefix(imgTag, "test_") {
 			actual = append(actual, imgDigest)

integration-cli/docker_cli_logs_test.go

@@ -217,8 +217,8 @@ func (s *DockerCLILogsSuite) TestLogsSinceFutureFollow(c *testing.T) {
 	since := t.Unix() + 2
 	out := cli.DockerCmd(c, "logs", "-t", "-f", fmt.Sprintf("--since=%v", since), name).Combined()
 	assert.Assert(c, out != "", "cannot read from empty log")
-	lines := strings.Split(strings.TrimSpace(out), "\n")
-	for _, v := range lines {
+	lines := strings.SplitSeq(strings.TrimSpace(out), "\n")
+	for v := range lines {
 		ts, err := time.Parse(time.RFC3339Nano, strings.Split(v, " ")[0])
 		assert.NilError(c, err, "cannot parse timestamp output from log: '%v'", v)
 		assert.Assert(c, ts.Unix() >= since, "earlier log found. since=%v logdate=%v", since, ts)

integration-cli/docker_cli_ps_test.go

@@ -531,7 +531,7 @@ func (s *DockerCLIPsSuite) TestPsListContainersFilterCreated(c *testing.T) {
 	out = cli.DockerCmd(c, "ps", "-a").Stdout()
 
 	hits := 0
-	for _, line := range strings.Split(out, "\n") {
+	for line := range strings.SplitSeq(out, "\n") {
 		if !strings.Contains(line, shortCID) {
 			continue
 		}

integration-cli/docker_cli_pull_test.go

@@ -157,7 +157,7 @@ func (s *DockerHubPullSuite) TestPullAllTagsFromCentralRegistry(c *testing.T) {
 
 	// Verify that the line for 'dockercore/engine-pull-all-test-fixture:latest' is left unchanged.
 	var latestLine string
-	for _, line := range strings.Split(outImageAllTagCmd, "\n") {
+	for line := range strings.SplitSeq(outImageAllTagCmd, "\n") {
 		if strings.HasPrefix(line, "dockercore/engine-pull-all-test-fixture") && strings.Contains(line, "latest") {
 			latestLine = line
 			break

integration-cli/docker_cli_push_test.go

@@ -79,7 +79,7 @@ func (s *DockerRegistrySuite) TestPushMultipleTags(c *testing.T) {
 	// Ensure layer list is equivalent for repoTag1 and repoTag2
 	out1 := cli.DockerCmd(c, "push", repoTag1).Combined()
 	var out1Lines []string
-	for _, outputLine := range strings.Split(out1, "\n") {
+	for outputLine := range strings.SplitSeq(out1, "\n") {
 		if strings.Contains(outputLine, imageAlreadyExists) {
 			out1Lines = append(out1Lines, outputLine)
 		}
@@ -87,7 +87,7 @@ func (s *DockerRegistrySuite) TestPushMultipleTags(c *testing.T) {
 
 	out2 := cli.DockerCmd(c, "push", repoTag2).Combined()
 	var out2Lines []string
-	for _, outputLine := range strings.Split(out2, "\n") {
+	for outputLine := range strings.SplitSeq(out2, "\n") {
 		if strings.Contains(outputLine, imageAlreadyExists) {
 			out2Lines = append(out2Lines, outputLine)
 		}

integration-cli/docker_utils_test.go

@@ -55,8 +55,8 @@ func getContainerCount(t *testing.T) int {
 	result := icmd.RunCommand(dockerBinary, "info")
 	result.Assert(t, icmd.Success)
 
-	lines := strings.Split(result.Combined(), "\n")
-	for _, line := range lines {
+	lines := strings.SplitSeq(result.Combined(), "\n")
+	for line := range lines {
 		if strings.Contains(line, containers) {
 			output := strings.TrimSpace(line)
 			output = strings.TrimPrefix(output, containers)
@@ -435,7 +435,7 @@ func loadSpecialImage(t *testing.T, imageFunc specialimage.SpecialImageFunc) str
 
 	out := cli.DockerCmd(t, "load", "-i", imgTar).Stdout()
 
-	for _, line := range strings.Split(out, "\n") {
+	for line := range strings.SplitSeq(out, "\n") {
 		line = strings.TrimSpace(line)
 
 		if _, imageID, hasID := strings.Cut(line, "Loaded image ID: "); hasID {

integration-cli/events_utils_test.go

@@ -102,8 +102,8 @@ func (e *eventObserver) CheckEventError(t *testing.T, id, event string, match ev
 	if e.disconnectionError != nil {
 		until := daemonUnixTime(t)
 		out := cli.DockerCmd(t, "events", "--since", e.startTime, "--until", until).Stdout()
-		events := strings.Split(strings.TrimSpace(out), "\n")
-		for _, e := range events {
+		events := strings.SplitSeq(strings.TrimSpace(out), "\n")
+		for e := range events {
 			if _, ok := match(e); ok {
 				foundEvent = true
 				break
@@ -176,7 +176,7 @@ func matchEventID(matches map[string]string, id string) bool {
 	if !matchID && matches["attributes"] != "" {
 		// try matching a name in the attributes
 		attributes := map[string]string{}
-		for _, a := range strings.Split(matches["attributes"], ", ") {
+		for a := range strings.SplitSeq(matches["attributes"], ", ") {
 			kv := strings.Split(a, "=")
 			attributes[kv[0]] = kv[1]
 		}
@@ -186,8 +186,8 @@ func matchEventID(matches map[string]string, id string) bool {
 }
 
 func parseEvents(t *testing.T, out, match string) {
-	events := strings.Split(strings.TrimSpace(out), "\n")
-	for _, event := range events {
+	events := strings.SplitSeq(strings.TrimSpace(out), "\n")
+	for event := range events {
 		matches := eventstestutils.ScanMap(event)
 		matched, err := regexp.MatchString(match, matches["action"])
 		assert.NilError(t, err)

integration-cli/utils_test.go

@@ -24,7 +24,7 @@ func getPrefixAndSlashFromDaemonPlatform() (prefix, slash string) {
 // a map which cgroup name as key and path as value.
 func ParseCgroupPaths(procCgroupData string) map[string]string {
 	cgroupPaths := map[string]string{}
-	for _, line := range strings.Split(procCgroupData, "\n") {
+	for line := range strings.SplitSeq(procCgroupData, "\n") {
 		parts := strings.Split(line, ":")
 		if len(parts) != 3 {
 			continue
@@ -120,7 +120,7 @@ func existingElements(t *testing.T, opts elementListOptions) []string {
 	}
 	out := cli.DockerCmd(t, args...).Combined()
 	var lines []string
-	for _, l := range strings.Split(out, "\n") {
+	for l := range strings.SplitSeq(out, "\n") {
 		if l != "" {
 			lines = append(lines, l)
 		}

integration/build/build_test.go

@@ -861,7 +861,7 @@ type buildLine struct {
 
 func getImageIDsFromBuild(output []byte) ([]string, error) {
 	var ids []string
-	for _, line := range bytes.Split(output, []byte("\n")) {
+	for line := range bytes.SplitSeq(output, []byte("\n")) {
 		if len(line) == 0 {
 			continue
 		}

integration/network/bridge/bridge_linux_test.go

@@ -891,7 +891,7 @@ func TestFirewallBackendSwitch(t *testing.T) {
 		})
 
 		// TODO: (When Go 1.24 is min version) Replace with `strings.Lines(dump)`.
-		for _, line := range strings.Split(dump, "\n") {
+		for line := range strings.SplitSeq(dump, "\n") {
 			line = strings.TrimSpace(line)
 			if line == "" {
 				continue

integration/networking/bridge_linux_test.go

@@ -1591,7 +1591,7 @@ func checkProxies(ctx context.Context, t *testing.T, c *client.Client, daemonPid
 		t.Error(res)
 		return
 	}
-	for _, line := range strings.Split(res.Stdout(), "\n") {
+	for line := range strings.SplitSeq(res.Stdout(), "\n") {
 		_, args, ok := strings.Cut(line, "docker-proxy")
 		if !ok {
 			continue
@@ -1785,7 +1785,7 @@ func TestAdvertiseAddresses(t *testing.T) {
 			// the associated MAC address.
 			findNeighMAC := func(neighOut, ip string) string {
 				t.Helper()
-				for _, line := range strings.Split(neighOut, "\n") {
+				for line := range strings.SplitSeq(neighOut, "\n") {
 					// Lines look like ...
 					// 172.22.22.22 dev eth0 lladdr 36:bc:ce:67:f3:e4 ref 1 used 0/7/0 probes 1 DELAY
 					fields := strings.Fields(line)
@@ -2015,7 +2015,7 @@ func TestLegacyLinksEnvVars(t *testing.T) {
 
 			// Check the list of environment variables set in the linking container.
 			var found bool
-			for _, l := range strings.Split(exportRes.Stdout.String(), "\n") {
+			for l := range strings.SplitSeq(exportRes.Stdout.String(), "\n") {
 				if strings.HasPrefix(l, "export CTR1_") {
 					// Legacy links env var found, but not expected.
 					if !tc.expectEnvVars {

integration/networking/port_mapping_linux_test.go

@@ -281,8 +281,8 @@ func enableIPv6OnAll(t *testing.T) func() {
 	ifaces := map[string]string{}
 	var allVal string
 
-	sysctls := strings.Split(string(out), "\n")
-	for _, sysctl := range sysctls {
+	sysctls := strings.SplitSeq(string(out), "\n")
+	for sysctl := range sysctls {
 		if sysctl == "" {
 			continue
 		}

pkg/parsers/operatingsystem/operatingsystem_linux.go

@@ -71,7 +71,7 @@ func IsContainerized() (bool, error) {
 	if err != nil {
 		return false, err
 	}
-	for _, line := range bytes.Split(b, []byte{'\n'}) {
+	for line := range bytes.SplitSeq(b, []byte{'\n'}) {
 		if len(line) > 0 && !bytes.HasSuffix(line, []byte(":/")) && !bytes.HasSuffix(line, []byte(":/init.scope")) {
 			return true, nil
 		}

pkg/sysinfo/sysinfo_linux.go

@@ -55,7 +55,7 @@ func findCgroupV1Mountpoints() (map[string]string, error) {
 
 	mps := make(map[string]string)
 	for _, mi := range mounts {
-		for _, opt := range strings.Split(mi.VFSOptions, ",") {
+		for opt := range strings.SplitSeq(mi.VFSOptions, ",") {
 			seen, known := allMap[opt]
 			if known && !seen {
 				allMap[opt] = true
@@ -375,7 +375,7 @@ func parseUintList(val string, maximum int) (map[int]struct{}, error) {
 	availableInts := make(map[int]struct{})
 	errInvalidFormat := fmt.Errorf("invalid format: %s", val)
 
-	for _, r := range strings.Split(val, ",") {
+	for r := range strings.SplitSeq(val, ",") {
 		if !strings.Contains(r, "-") {
 			v, err := strconv.Atoi(r)
 			if err != nil {