refactor: Simplify code with modernize linter

Author: alexandear

.golangci.yml

@@ -41,6 +41,7 @@ linters:
     - govet
     - ineffassign
     - misspell
+    - modernize
     - revive
     - staticcheck
     - unused
@@ -74,6 +75,11 @@ linters:
 
       # tab width in spaces. Default to 1.
       tab-width: 1
+    modernize:
+      disable:
+        - any
+        - stringsbuilder
+        - omitzero
     nakedret:
       # make an issue if func has more lines of code than this setting and it has naked returns; default is 30
       max-func-lines: 30

cmd/ec2geninfo/main.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"regexp"
+	"slices"
 	"text/template"
 
 	"github.com/aws/aws-sdk-go-v2/aws"
@@ -157,11 +158,8 @@ func getEC2Instances(region string, instances map[string]InstanceInfo) (map[stri
 
 			cbrSupported := false
 			if inst.SupportedUsageClasses != nil {
-				for _, usageClass := range inst.SupportedUsageClasses {
-					if usageClass == types.UsageClassTypeCapacityBlock {
-						cbrSupported = true
-						break
-					}
+				if slices.Contains(inst.SupportedUsageClasses, types.UsageClassTypeCapacityBlock) {
+					cbrSupported = true
 				}
 			}
 

integration/tests/crud/creategetdelete_test.go

@@ -492,8 +492,8 @@ var _ = Describe("(Integration) Create, Get, Scale & Delete", func() {
 				Expect(js).To(ContainElement(HavePrefix("AWS_SESSION_OBJECT=")))
 
 				for _, envVar := range js {
-					if strings.HasPrefix(envVar, "AWS_SESSION_OBJECT=") {
-						err := json.Unmarshal([]byte(strings.TrimPrefix(envVar, "AWS_SESSION_OBJECT=")), &so)
+					if after, ok := strings.CutPrefix(envVar, "AWS_SESSION_OBJECT="); ok {
+						err := json.Unmarshal([]byte(after), &so)
 						Expect(err).ShouldNot(HaveOccurred())
 					}
 				}

integration/tests/dry_run/dry_run_test.go

@@ -167,7 +167,7 @@ var _ = Describe("(Integration) [Dry-Run test]", func() {
 	parseOutput := func(output []byte) (*api.ClusterConfig, *api.ClusterConfig) {
 		actual, err := eks.ParseConfig(output)
 		Expect(err).NotTo(HaveOccurred())
-		defaultConfig, err := eks.ParseConfig([]byte(fmt.Sprintf(defaultClusterConfig, params.ClusterName)))
+		defaultConfig, err := eks.ParseConfig(fmt.Appendf(nil, defaultClusterConfig, params.ClusterName))
 		Expect(err).NotTo(HaveOccurred())
 		return actual, defaultConfig
 	}

pkg/actions/accessentry/creator_test.go

@@ -28,11 +28,10 @@ var _ = Describe("Access Entry", func() {
 		s.CreateStackStub = func(ctx context.Context, stackName string, r builder.ResourceSetReader, tags map[string]string, parameters map[string]string, errorCh chan error) error {
 			defer close(errorCh)
 			prefix := fmt.Sprintf("eksctl-%s-accessentry-", ae.clusterName)
-			idx := strings.Index(stackName, prefix)
-			if idx < 0 {
+			_, suffix, ok := strings.Cut(stackName, prefix)
+			if !ok {
 				return fmt.Errorf("expected stack name to have prefix %q", prefix)
 			}
-			suffix := stackName[idx+len(prefix):]
 			_, err := base32.StdEncoding.WithPadding(base32.NoPadding).DecodeString(suffix)
 			if err != nil {
 				return fmt.Errorf("expected stack name to have a base32-encoded suffix: %w", err)

pkg/actions/accessentry/migrator_test.go

@@ -59,11 +59,10 @@ var _ = Describe("Migrate Access Entry", func() {
 		s.CreateStackStub = func(ctx context.Context, stackName string, r builder.ResourceSetReader, tags map[string]string, parameters map[string]string, errorCh chan error) error {
 			defer close(errorCh)
 			prefix := fmt.Sprintf("eksctl-%s-accessentry-", clusterName)
-			idx := strings.Index(stackName, prefix)
-			if idx < 0 {
+			_, suffix, ok := strings.Cut(stackName, prefix)
+			if !ok {
 				return fmt.Errorf("expected stack name to have prefix %q", prefix)
 			}
-			suffix := stackName[idx+len(prefix):]
 			_, err := base32.StdEncoding.WithPadding(base32.NoPadding).DecodeString(suffix)
 			if err != nil {
 				return fmt.Errorf("expected stack name to have a base32-encoded suffix: %w", err)

pkg/actions/addon/create.go

@@ -319,7 +319,7 @@ func (a *Manager) patchAWSNodeSA(ctx context.Context) error {
 		return nil
 	}
 
-	_, err = serviceAccounts.Patch(ctx, "aws-node", types.JSONPatchType, []byte(fmt.Sprintf(`[{"op": "remove", "path": "/metadata/managedFields/%d"}]`, managerIndex)), metav1.PatchOptions{})
+	_, err = serviceAccounts.Patch(ctx, "aws-node", types.JSONPatchType, fmt.Appendf(nil, `[{"op": "remove", "path": "/metadata/managedFields/%d"}]`, managerIndex), metav1.PatchOptions{})
 	if err != nil {
 		return fmt.Errorf("failed to patch sa: %w", err)
 	}
@@ -387,7 +387,7 @@ func (a *Manager) patchAWSNodeDaemonSet(ctx context.Context) error {
 		}
 	}
 
-	_, err = daemonSets.Patch(ctx, "aws-node", types.JSONPatchType, []byte(fmt.Sprintf(`[{"op": "remove", "path": "/metadata/managedFields/%d"}]`, managerIndex)), metav1.PatchOptions{})
+	_, err = daemonSets.Patch(ctx, "aws-node", types.JSONPatchType, fmt.Appendf(nil, `[{"op": "remove", "path": "/metadata/managedFields/%d"}]`, managerIndex), metav1.PatchOptions{})
 	if err != nil {
 		return fmt.Errorf("failed to patch daemon set: %w", err)
 	}

pkg/actions/anywhere/anywhere.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"slices"
 
 	"github.com/weaveworks/eksctl/pkg/version"
 )
@@ -26,10 +27,8 @@ func IsAnywhereCommand(args []string) (bool, error) {
 
 	// if they have any args/flags before the anywhere command we should error
 	// e.g. eksctl --foo=bar anywhere should error
-	for _, arg := range args {
-		if arg == "anywhere" {
-			return false, fmt.Errorf("flags cannot be placed before the anywhere command")
-		}
+	if slices.Contains(args, "anywhere") {
+		return false, fmt.Errorf("flags cannot be placed before the anywhere command")
 	}
 
 	return false, nil

pkg/actions/capability/creator.go

@@ -6,6 +6,7 @@ import (
 	"encoding/base32"
 	"errors"
 	"fmt"
+	"maps"
 	"strings"
 	"time"
 
@@ -128,9 +129,7 @@ func (c *Creator) createCapabilityStack(ctx context.Context, capability *api.Cap
 		api.ClusterNameTag:    c.clusterName,
 		api.CapabilityNameTag: capability.Name,
 	}
-	for k, v := range capability.Tags {
-		tags[k] = v
-	}
+	maps.Copy(tags, capability.Tags)
 	if err := c.stackCreator.CreateStack(ctx, stackName, rs, tags, nil, stackErrCh); err != nil {
 		return err
 	}
@@ -154,9 +153,7 @@ func (c *Creator) createIAMRoleStack(ctx context.Context, capability *api.Capabi
 		api.CapabilityIAMRoleTag: capability.Name,
 	}
 
-	for k, v := range capability.Tags {
-		tags[k] = v
-	}
+	maps.Copy(tags, capability.Tags)
 
 	stackCh := make(chan error)
 	if err := c.stackCreator.CreateStack(ctx, stackName, rs, tags, nil, stackCh); err != nil {

pkg/actions/karpenter/create_test.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	"slices"
 
 	awseks "github.com/aws/aws-sdk-go-v2/service/eks"
 	ekstypes "github.com/aws/aws-sdk-go-v2/service/eks/types"
@@ -451,12 +452,7 @@ var _ = Describe("Create", func() {
 					Cluster: fakeCluster,
 				}, nil)
 				p.MockEC2().On("CreateTags", mock.Anything, mock.MatchedBy(func(input *ec2.CreateTagsInput) bool {
-					for _, r := range input.Resources {
-						if r == "sg-cluster-1234" {
-							return true
-						}
-					}
-					return false
+					return slices.Contains(input.Resources, "sg-cluster-1234")
 				})).Return(nil, errors.New("tag failed"))
 			})
 			It("errors", func() {