refactor: modernize go code with stdlib improvements

cmd/argo/commands/executorplugin/io.go

@@ -41,7 +41,7 @@ func loadPluginManifest(pluginDir string) (*spec.Plugin, error) {
 }
 
 func addHeader(x []byte, h string) []byte {
-	return []byte(fmt.Sprintf("%s\n%s", h, string(x)))
+	return fmt.Appendf(nil, "%s\n%s", h, string(x))
 }
 
 func addCodegenHeader(x []byte) []byte {

cmd/argoexec/commands/emissary_windows_test.go

@@ -6,10 +6,11 @@ import (
 	"os"
 	"testing"
 
-	cmdutil "github.com/argoproj/argo-workflows/v3/util/cmd"
-	"github.com/argoproj/argo-workflows/v3/util/errors"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+
+	cmdutil "github.com/argoproj/argo-workflows/v3/util/cmd"
+	"github.com/argoproj/argo-workflows/v3/util/errors"
 )
 
 func TestEmissary(t *testing.T) {

hack/docs/configdoc.go

@@ -274,19 +274,19 @@ func createTypeLinkWithSpacing(baseType string) (string, bool) {
 		return fmt.Sprintf("[`%s`](#%s)", cleanBaseType, strings.ToLower(baseType)), true
 	}
 
-	if strings.HasPrefix(baseType, "wfv1.") {
-		wfType := strings.TrimPrefix(baseType, "wfv1.")
+	if after, ok := strings.CutPrefix(baseType, "wfv1."); ok {
+		wfType := after
 		return fmt.Sprintf("[`%s`](fields.md#%s)", wfType, strings.ToLower(wfType)), true
 	}
 
-	if strings.HasPrefix(baseType, "apiv1.") {
-		typeName := strings.TrimPrefix(baseType, "apiv1.")
+	if after, ok := strings.CutPrefix(baseType, "apiv1."); ok {
+		typeName := after
 		anchor := strings.ToLower(typeName)
 		return fmt.Sprintf("[`%s`](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.32/#%s-v1-core)", typeName, anchor), true
 	}
 
-	if strings.HasPrefix(baseType, "metav1.") {
-		typeName := strings.TrimPrefix(baseType, "metav1.")
+	if after, ok := strings.CutPrefix(baseType, "metav1."); ok {
+		typeName := after
 		anchor := strings.ToLower(typeName)
 		return fmt.Sprintf("[`%s`](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.32/#%s-v1-meta)", typeName, anchor), true
 	}

hack/featuregen/contents.go

@@ -186,7 +186,7 @@ func format(version string, features []feature) string {
 			output.WriteString(fmt.Sprintf("- %s by %s %s\n", feature.Description, feature.Author, issuesStr))
 
 			if feature.Details != "" {
-				for _, line := range strings.Split(feature.Details, "\n") {
+				for line := range strings.SplitSeq(feature.Details, "\n") {
 					if line != "" {
 						output.WriteString(fmt.Sprintf("  %s\n", line))
 					}

server/utils/list_options.go

@@ -92,14 +92,14 @@ func BuildListOptions(options metav1.ListOptions, ns, namePrefix, nameFilter, cr
 		}
 	}
 	showRemainingItemCount := false
-	for _, selector := range strings.Split(options.FieldSelector, ",") {
+	for selector := range strings.SplitSeq(options.FieldSelector, ",") {
 		if len(selector) == 0 {
 			continue
 		}
-		if strings.HasPrefix(selector, "metadata.namespace=") {
+		if after, ok := strings.CutPrefix(selector, "metadata.namespace="); ok {
 			// for backward compatibility, the field selector 'metadata.namespace' is supported for now despite the addition
 			// of the new 'namespace' query parameter, which is what the UI uses
-			fieldSelectedNamespace := strings.TrimPrefix(selector, "metadata.namespace=")
+			fieldSelectedNamespace := after
 			switch namespace {
 			case "":
 				namespace = fieldSelectedNamespace
@@ -109,16 +109,16 @@ func BuildListOptions(options metav1.ListOptions, ns, namePrefix, nameFilter, cr
 				return ListOptions{}, status.Errorf(codes.InvalidArgument,
 					"'namespace' query param (%q) and fieldselector 'metadata.namespace' (%q) are both specified and contradict each other", namespace, fieldSelectedNamespace)
 			}
-		} else if strings.HasPrefix(selector, "metadata.name=") {
-			name = strings.TrimPrefix(selector, "metadata.name=")
-		} else if strings.HasPrefix(selector, "spec.startedAt>") {
-			minStartedAt, err = time.Parse(time.RFC3339, strings.TrimPrefix(selector, "spec.startedAt>"))
+		} else if after, ok := strings.CutPrefix(selector, "metadata.name="); ok {
+			name = after
+		} else if after, ok := strings.CutPrefix(selector, "spec.startedAt>"); ok {
+			minStartedAt, err = time.Parse(time.RFC3339, after)
 			if err != nil {
 				// startedAt is populated by us, it should therefore be valid.
 				return ListOptions{}, ToStatusError(err, codes.Internal)
 			}
-		} else if strings.HasPrefix(selector, "spec.startedAt<") {
-			maxStartedAt, err = time.Parse(time.RFC3339, strings.TrimPrefix(selector, "spec.startedAt<"))
+		} else if after, ok := strings.CutPrefix(selector, "spec.startedAt<"); ok {
+			maxStartedAt, err = time.Parse(time.RFC3339, after)
 			if err != nil {
 				// no need to use sutils here
 				return ListOptions{}, ToStatusError(err, codes.Internal)

server/workflow/workflow_server.go

@@ -250,10 +250,7 @@ func (s *workflowServer) ListWorkflows(ctx context.Context, req *workflowpkg.Wor
 	var remainCount int64
 	if options.ShowRemainingItemCount {
 		// Calculate exact remaining count when requested
-		remainCount = totalCount - int64(options.Offset) - int64(len(wfs))
-		if remainCount < 0 {
-			remainCount = 0
-		}
+		remainCount = max(totalCount-int64(options.Offset)-int64(len(wfs)), 0)
 		meta.RemainingItemCount = &remainCount
 	} else {
 		// For pagination without remaining count, use the efficient HasMoreWorkflows method

test/e2e/fixtures/given.go

@@ -71,8 +71,8 @@ func (g *Given) WorkflowWorkflow(wf *wfv1.Workflow) *Given {
 func (g *Given) readResource(text string, v metav1.Object) {
 	g.t.Helper()
 	var file string
-	if strings.HasPrefix(text, "@") {
-		file = strings.TrimPrefix(text, "@")
+	if after, ok := strings.CutPrefix(text, "@"); ok {
+		file = after
 	} else {
 		f, err := os.CreateTemp("", "argo_e2e")
 		if err != nil {

test/e2e/fixtures/metrics.go

@@ -95,9 +95,9 @@ func (mb *MetricBaseline) ExpectIncrease() {
 func parseMetricValue(body, metricPattern string) float64 {
 	// Escape special regex characters in the metric pattern, but keep the spaces
 	// We'll look for lines that match the pattern and extract the value
-	lines := strings.Split(body, "\n")
+	lines := strings.SplitSeq(body, "\n")
 
-	for _, line := range lines {
+	for line := range lines {
 		line = strings.TrimSpace(line)
 		if line == "" || strings.HasPrefix(line, "#") {
 			continue

test/e2e/fixtures/util.go

@@ -26,7 +26,7 @@ func Exec(name string, args ...string) (string, error) {
 	if err != nil {
 		errorln(err)
 	}
-	for _, s := range strings.Split(output, "\n") {
+	for s := range strings.SplitSeq(output, "\n") {
 		_, _ = fmt.Println(s)
 	}
 	return output, err
@@ -56,8 +56,8 @@ func runWithTimeout(cmd *exec.Cmd) (string, error) {
 // LoadObject is used to load yaml to runtime.Object
 func LoadObject(text string) (runtime.Object, error) {
 	var yaml string
-	if strings.HasPrefix(text, "@") {
-		file := strings.TrimPrefix(text, "@")
+	if after, ok := strings.CutPrefix(text, "@"); ok {
+		file := after
 		f, err := os.ReadFile(filepath.Clean(file))
 		if err != nil {
 			return nil, err

test/e2e/fixtures/when.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"maps"
 	"reflect"
 	"strconv"
 	"strings"
@@ -601,9 +602,7 @@ func (w *When) CreateConfigMap(name string, data map[string]string, customLabels
 
 	labels := map[string]string{Label: "true"}
 
-	for k, v := range customLabels {
-		labels[k] = v
-	}
+	maps.Copy(labels, customLabels)
 
 	ctx := logging.TestContext(w.t.Context())
 	_, err := w.kubeClient.CoreV1().ConfigMaps(Namespace).Create(ctx, &corev1.ConfigMap{
@@ -621,9 +620,7 @@ func (w *When) UpdateConfigMap(name string, data map[string]string, customLabels
 
 	labels := map[string]string{Label: "true"}
 
-	for k, v := range customLabels {
-		labels[k] = v
-	}
+	maps.Copy(labels, customLabels)
 
 	ctx := logging.TestContext(w.t.Context())
 	_, err := w.kubeClient.CoreV1().ConfigMaps(Namespace).Update(ctx, &corev1.ConfigMap{

util/fields/fields.go

@@ -12,7 +12,7 @@ func NewCleaner(x string) Cleaner {
 			x = x[1:]
 			y.exclude = true
 		}
-		for _, field := range strings.Split(x, ",") {
+		for field := range strings.SplitSeq(x, ",") {
 			y.fields[field] = true
 		}
 	}

util/logging/slog.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"log/slog"
+	"maps"
 	"os"
 )
 
@@ -80,13 +81,9 @@ func (s *slogLogger) Level() Level {
 func (s *slogLogger) WithFields(fields Fields) Logger {
 	newFields := make(Fields)
 
-	for k, v := range s.fields {
-		newFields[k] = v
-	}
+	maps.Copy(newFields, s.fields)
 
-	for k, v := range fields {
-		newFields[k] = v
-	}
+	maps.Copy(newFields, fields)
 
 	return &slogLogger{
 		fields:    newFields,
@@ -101,9 +98,7 @@ func (s *slogLogger) WithFields(fields Fields) Logger {
 func (s *slogLogger) WithField(name string, value any) Logger {
 	newFields := make(Fields)
 
-	for k, v := range s.fields {
-		newFields[k] = v
-	}
+	maps.Copy(newFields, s.fields)
 
 	newFields[name] = value
 

util/resource/duration.go

@@ -1,6 +1,8 @@
 package resource
 
 import (
+	"maps"
+
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
 
@@ -18,12 +20,8 @@ func DurationForPod(pod *corev1.Pod) wfv1.ResourcesDuration {
 			corev1.ResourceMemory: resource.MustParse("100Mi"),
 		}}
 		// Update with user-configured resources (falls back to limits as == requests, same as Kubernetes).
-		for name, quantity := range c.Resources.Limits {
-			summaries[c.Name].ResourceList[name] = quantity
-		}
-		for name, quantity := range c.Resources.Requests {
-			summaries[c.Name].ResourceList[name] = quantity
-		}
+		maps.Copy(summaries[c.Name].ResourceList, c.Resources.Limits)
+		maps.Copy(summaries[c.Name].ResourceList, c.Resources.Requests)
 	}
 	for _, c := range append(pod.Status.InitContainerStatuses, pod.Status.ContainerStatuses...) {
 		summaries[c.Name] = Summary{ResourceList: summaries[c.Name].ResourceList, ContainerState: c.State}

util/telemetry/builder/builder.go

@@ -105,7 +105,7 @@ func upperToSnake(in string) string {
 	in = string(append([]rune{unicode.ToLower(runes[0])}, runes[1:]...))
 	re := regexp.MustCompile(`[A-Z]`)
 	return string(re.ReplaceAllFunc([]byte(in), func(in []byte) []byte {
-		return []byte(fmt.Sprintf("_%s", strings.ToLower(string(in[0]))))
+		return fmt.Appendf(nil, "_%s", strings.ToLower(string(in[0])))
 	}))
 }
 

util/template/expression_template.go

@@ -36,7 +36,7 @@ func expressionReplace(ctx context.Context, w io.Writer, expression string, env
 	log := logging.RequireLoggerFromContext(ctx)
 	// The template is JSON-marshaled. This JSON-unmarshals the expression to undo any character escapes.
 	var unmarshalledExpression string
-	err := json.Unmarshal([]byte(fmt.Sprintf(`"%s"`, expression)), &unmarshalledExpression)
+	err := json.Unmarshal(fmt.Appendf(nil, `"%s"`, expression), &unmarshalledExpression)
 	if err != nil && allowUnresolved {
 		log.WithError(err).Debug(ctx, "unresolved is allowed ")
 		return fmt.Fprintf(w, "{{%s%s}}", kindExpression, expression)

util/template/kind.go

@@ -21,8 +21,8 @@ func registerKind(k kind) {
 
 func parseTag(tag string) (kind, string) {
 	for _, k := range kinds {
-		if strings.HasPrefix(tag, k) {
-			return k, jsonutil.Fix(strings.TrimPrefix(tag, k))
+		if after, ok := strings.CutPrefix(tag, k); ok {
+			return k, jsonutil.Fix(after)
 		}
 	}
 	return kindSimple, tag

workflow/common/convert.go

@@ -2,6 +2,7 @@ package common
 
 import (
 	"context"
+	"maps"
 	"time"
 
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -94,14 +95,10 @@ func toWorkflow(cronWf wfv1.CronWorkflow, objectMeta metav1.ObjectMeta) *wfv1.Wo
 
 	wf.Labels[LabelKeyCronWorkflow] = cronWf.Name
 	if cronWf.Spec.WorkflowMetadata != nil {
-		for key, label := range cronWf.Spec.WorkflowMetadata.Labels {
-			wf.Labels[key] = label
-		}
+		maps.Copy(wf.Labels, cronWf.Spec.WorkflowMetadata.Labels)
 
 		if len(cronWf.Spec.WorkflowMetadata.Annotations) > 0 {
-			for key, annotation := range cronWf.Spec.WorkflowMetadata.Annotations {
-				wf.Annotations[key] = annotation
-			}
+			maps.Copy(wf.Annotations, cronWf.Spec.WorkflowMetadata.Annotations)
 		}
 
 		wf.Finalizers = append(wf.Finalizers, cronWf.Spec.WorkflowMetadata.Finalizers...)

workflow/common/params.go

@@ -1,24 +1,22 @@
 package common
 
+import "maps"
+
 // Parameters extends string map with useful methods.
 type Parameters map[string]string
 
 // Merge merges given parameters.
 func (ps Parameters) Merge(args ...Parameters) Parameters {
 	newParams := ps.DeepCopy()
 	for _, params := range args {
-		for k, v := range params {
-			newParams[k] = v
-		}
+		maps.Copy(newParams, params)
 	}
 	return newParams
 }
 
 // DeepCopy returns a new instance which has the same parameters as the receiver.
 func (ps Parameters) DeepCopy() Parameters {
 	newParams := make(Parameters)
-	for k, v := range ps {
-		newParams[k] = v
-	}
+	maps.Copy(newParams, ps)
 	return newParams
 }

workflow/controller/artifact_gc.go

@@ -538,12 +538,8 @@ func (woc *wfOperationCtx) createArtifactGCPod(ctx context.Context, strategy wfv
 	if podInfo.serviceAccount != "" {
 		pod.Spec.ServiceAccountName = podInfo.serviceAccount
 	}
-	for label, labelVal := range podInfo.podMetadata.Labels {
-		pod.Labels[label] = labelVal
-	}
-	for annotation, annotationVal := range podInfo.podMetadata.Annotations {
-		pod.Annotations[annotation] = annotationVal
-	}
+	maps.Copy(pod.Labels, podInfo.podMetadata.Labels)
+	maps.Copy(pod.Annotations, podInfo.podMetadata.Annotations)
 
 	if v := woc.controller.Config.InstanceID; v != "" {
 		pod.Labels[common.EnvVarInstanceID] = v
@@ -771,15 +767,11 @@ func (woc *wfOperationCtx) updateArtifactGCPodInfo(artifactGC *wfv1.ArtifactGC,
 		if len(artifactGC.PodMetadata.Labels) > 0 && podInfo.podMetadata.Labels == nil {
 			podInfo.podMetadata.Labels = make(map[string]string)
 		}
-		for labelKey, labelValue := range artifactGC.PodMetadata.Labels {
-			podInfo.podMetadata.Labels[labelKey] = labelValue
-		}
+		maps.Copy(podInfo.podMetadata.Labels, artifactGC.PodMetadata.Labels)
 		if len(artifactGC.PodMetadata.Annotations) > 0 && podInfo.podMetadata.Annotations == nil {
 			podInfo.podMetadata.Annotations = make(map[string]string)
 		}
-		for annotationKey, annotationValue := range artifactGC.PodMetadata.Annotations {
-			podInfo.podMetadata.Annotations[annotationKey] = annotationValue
-		}
+		maps.Copy(podInfo.podMetadata.Annotations, artifactGC.PodMetadata.Annotations)
 	}
 
 }

workflow/controller/scope.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"maps"
 
 	"github.com/expr-lang/expr"
 
@@ -61,9 +62,7 @@ func (s *wfScope) addArtifactToScope(key string, artifact wfv1.Artifact) {
 // resolveVar resolves a parameter or artifact
 func (s *wfScope) resolveVar(v string) (interface{}, error) {
 	m := make(map[string]interface{})
-	for k, v := range s.scope {
-		m[k] = v
-	}
+	maps.Copy(m, s.scope)
 	if s.tmpl != nil {
 		for _, a := range s.tmpl.Inputs.Artifacts {
 			m["inputs.artifacts."+a.Name] = a // special case for artifacts