chore: enable errorlint

Signed-off-by: Matthieu MOREL <matthieu.morel35@gmail.com>

.golangci.yml

@@ -20,6 +20,7 @@ linters:
   enable:
     - depguard
     - dupl
+    - errorlint
     - gomodguard
     - govet
     - ineffassign

cmd/helm/helm.go

@@ -17,6 +17,7 @@ limitations under the License.
 package main // import "helm.sh/helm/v4/cmd/helm"
 
 import (
+	"errors"
 	"log/slog"
 	"os"
 
@@ -41,8 +42,9 @@ func main() {
 	}
 
 	if err := cmd.Execute(); err != nil {
-		switch e := err.(type) {
+		var e helmcmd.PluginError
-		case helmcmd.PluginError:
+		switch {
+		case errors.As(err, &e):
 			os.Exit(e.Code)
 		default:
 			os.Exit(1)

cmd/helm/helm_test.go

@@ -22,6 +22,8 @@ import (
 	"os/exec"
 	"runtime"
 	"testing"
+
+	"github.com/stretchr/testify/require"
 )
 
 func TestPluginExitCode(t *testing.T) {
@@ -57,11 +59,9 @@ func TestPluginExitCode(t *testing.T) {
 		cmd.Stdout = stdout
 		cmd.Stderr = stderr
 		err := cmd.Run()
-		exiterr, ok := err.(*exec.ExitError)
+		var exiterr *exec.ExitError
 
-		if !ok {
+		require.ErrorAs(t, err, &exiterr, "Unexpected error returned by os.Exit: %T", err)
-			t.Fatalf("Unexpected error returned by os.Exit: %T", err)
-		}
 
 		if stdout.String() != "" {
 			t.Errorf("Expected no write to stdout: Got %q", stdout.String())

internal/chart/v3/loader/archive.go

@@ -72,8 +72,8 @@ func LoadFile(name string) (*chart.Chart, error) {
 
 	c, err := LoadArchive(raw)
 	if err != nil {
-		if err == gzip.ErrHeader {
+		if errors.Is(err, gzip.ErrHeader) {
-			return nil, fmt.Errorf("file '%s' does not appear to be a valid chart file (details: %s)", name, err)
+			return nil, fmt.Errorf("file '%s' does not appear to be a valid chart file (details: %w)", name, err)
 		}
 	}
 	return c, err
@@ -91,7 +91,7 @@ func ensureArchive(name string, raw *os.File) error {
 	buffer := make([]byte, 512)
 	_, err := raw.Read(buffer)
 	if err != nil && err != io.EOF {
-		return fmt.Errorf("file '%s' cannot be read: %s", name, err)
+		return fmt.Errorf("file '%s' cannot be read: %w", name, err)
 	}
 
 	// Helm may identify achieve of the application/x-gzip as application/vnd.ms-fontobject.
@@ -131,7 +131,7 @@ func LoadArchiveFiles(in io.Reader) ([]*BufferedFile, error) {
 	for {
 		b := bytes.NewBuffer(nil)
 		hd, err := tr.Next()
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			break
 		}
 		if err != nil {

internal/chart/v3/loader/load.go

@@ -186,7 +186,7 @@ func LoadValues(data io.Reader) (map[string]interface{}, error) {
 		currentMap := map[string]interface{}{}
 		raw, err := reader.Read()
 		if err != nil {
-			if err == io.EOF {
+			if errors.Is(err, io.EOF) {
 				break
 			}
 			return nil, fmt.Errorf("error reading yaml document: %w", err)

internal/chart/v3/metadata_test.go

@@ -16,6 +16,7 @@ limitations under the License.
 package v3
 
 import (
+	"errors"
 	"testing"
 )
 
@@ -181,7 +182,7 @@ func TestValidate(t *testing.T) {
 
 	for _, tt := range tests {
 		result := tt.md.Validate()
-		if result != tt.err {
+		if !errors.Is(result, tt.err) {
 			t.Errorf("expected %q, got %q in test %q", tt.err, result, tt.name)
 		}
 	}

internal/chart/v3/util/dependencies.go

@@ -16,6 +16,7 @@ limitations under the License.
 package util
 
 import (
+	"errors"
 	"log/slog"
 	"strings"
 
@@ -42,6 +43,7 @@ func processDependencyConditions(reqs []*chart.Dependency, cvals Values, cpath s
 			if len(c) > 0 {
 				// retrieve value
 				vv, err := cvals.PathValue(cpath + c)
+				var errNoValue ErrNoValue
 				if err == nil {
 					// if not bool, warn
 					if bv, ok := vv.(bool); ok {
@@ -49,7 +51,7 @@ func processDependencyConditions(reqs []*chart.Dependency, cvals Values, cpath s
 						break
 					}
 					slog.Warn("returned non-bool value", "path", c, "chart", r.Name)
-				} else if _, ok := err.(ErrNoValue); !ok {
+				} else if !errors.As(err, &errNoValue) {
 					// this is a real error
 					slog.Warn("the method PathValue returned error", slog.Any("error", err))
 				}

internal/chart/v3/util/dependencies_test.go

@@ -21,6 +21,8 @@ import (
 	"strconv"
 	"testing"
 
+	"github.com/stretchr/testify/require"
+
 	chart "helm.sh/helm/v4/internal/chart/v3"
 	"helm.sh/helm/v4/internal/chart/v3/loader"
 )
@@ -250,12 +252,8 @@ func TestProcessDependencyImportValues(t *testing.T) {
 	if err == nil {
 		t.Error("expect nil value not found but found it")
 	}
-	switch xerr := err.(type) {
+	var errNoValue ErrNoValue
-	case ErrNoValue:
+	require.ErrorAs(t, err, &errNoValue, "expected an ErrNoValue but got %q instead", err)
-		// We found what we expected
-	default:
-		t.Errorf("expected an ErrNoValue but got %q instead", xerr)
-	}
 
 	c = loadChart(t, "testdata/subpop")
 	if err := processDependencyImportValues(c, true); err != nil {

internal/sympath/walk.go

@@ -21,6 +21,7 @@ limitations under the License.
 package sympath
 
 import (
+	"errors"
 	"fmt"
 	"log/slog"
 	"os"
@@ -40,7 +41,7 @@ func Walk(root string, walkFn filepath.WalkFunc) error {
 	} else {
 		err = symwalk(root, info, walkFn)
 	}
-	if err == filepath.SkipDir {
+	if errors.Is(err, filepath.SkipDir) {
 		return nil
 	}
 	return err
@@ -75,7 +76,7 @@ func symwalk(path string, info os.FileInfo, walkFn filepath.WalkFunc) error {
 		if info, err = os.Lstat(resolved); err != nil {
 			return err
 		}
-		if err := symwalk(path, info, walkFn); err != nil && err != filepath.SkipDir {
+		if err := symwalk(path, info, walkFn); err != nil && !errors.Is(err, filepath.SkipDir) {
 			return err
 		}
 		return nil
@@ -98,13 +99,13 @@ func symwalk(path string, info os.FileInfo, walkFn filepath.WalkFunc) error {
 		filename := filepath.Join(path, name)
 		fileInfo, err := os.Lstat(filename)
 		if err != nil {
-			if err := walkFn(filename, fileInfo, err); err != nil && err != filepath.SkipDir {
+			if err := walkFn(filename, fileInfo, err); err != nil && !errors.Is(err, filepath.SkipDir) {
 				return err
 			}
 		} else {
 			err = symwalk(filename, fileInfo, walkFn)
 			if err != nil {
-				if (!fileInfo.IsDir() && !IsSymlink(fileInfo)) || err != filepath.SkipDir {
+				if (!fileInfo.IsDir() && !IsSymlink(fileInfo)) || !errors.Is(err, filepath.SkipDir) {
 					return err
 				}
 			}

internal/third_party/dep/fs/fs.go

@@ -164,7 +164,8 @@ func copyFile(src, dst string) (err error) {
 				//
 				// ERROR_PRIVILEGE_NOT_HELD is 1314 (0x522):
 				// https://msdn.microsoft.com/en-us/library/windows/desktop/ms681385(v=vs.85).aspx
-				if lerr, ok := err.(*os.LinkError); ok && lerr.Err != syscall.Errno(1314) {
+				var lerr *os.LinkError
+				if errors.As(err, &lerr) && !errors.Is(lerr.Err, syscall.Errno(1314)) {
 					return err
 				}
 			} else {

internal/third_party/dep/fs/fs_test.go

@@ -36,6 +36,8 @@ import (
 	"path/filepath"
 	"runtime"
 	"testing"
+
+	"github.com/stretchr/testify/require"
 )
 
 func TestRenameWithFallback(t *testing.T) {
@@ -234,9 +236,7 @@ func TestCopyDirFail_SrcIsNotDir(t *testing.T) {
 		t.Fatalf("expected error for CopyDir(%s, %s), got none", srcdir, dstdir)
 	}
 
-	if err != errSrcNotDir {
+	require.ErrorIsf(t, err, errSrcNotDir, "expected %v error for CopyDir(%s, %s), got %s", errSrcNotDir, srcdir, dstdir, err)
-		t.Fatalf("expected %v error for CopyDir(%s, %s), got %s", errSrcNotDir, srcdir, dstdir, err)
-	}
 
 }
 
@@ -260,9 +260,7 @@ func TestCopyDirFail_DstExists(t *testing.T) {
 		t.Fatalf("expected error for CopyDir(%s, %s), got none", srcdir, dstdir)
 	}
 
-	if err != errDstExist {
+	require.ErrorIsf(t, err, errDstExist, "expected %v error for CopyDir(%s, %s), got %s", errDstExist, srcdir, dstdir, err)
-		t.Fatalf("expected %v error for CopyDir(%s, %s), got %s", errDstExist, srcdir, dstdir, err)
-	}
 }
 
 func TestCopyDirFailOpen(t *testing.T) {

internal/third_party/dep/fs/rename.go

@@ -34,6 +34,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 package fs
 
 import (
+	"errors"
 	"fmt"
 	"os"
 	"syscall"
@@ -46,10 +47,10 @@ func renameFallback(err error, src, dst string) error {
 	// copy if we detect that case. syscall.EXDEV is the common name for the
 	// cross device link error which has varying output text across different
 	// operating systems.
-	terr, ok := err.(*os.LinkError)
+	var terr *os.LinkError
-	if !ok {
+	if !errors.As(err, &terr) {
 		return err
-	} else if terr.Err != syscall.EXDEV {
+	} else if !errors.Is(terr.Err, syscall.EXDEV) {
 		return fmt.Errorf("link error: cannot rename %s to %s: %w", src, dst, terr)
 	}
 

pkg/action/install.go

@@ -460,7 +460,7 @@ func (i *Install) performInstall(rel *release.Release, toBeAdopted kube.Resource
 	// pre-install hooks
 	if !i.DisableHooks {
 		if err := i.cfg.execHook(rel, release.HookPreInstall, i.WaitStrategy, i.Timeout); err != nil {
-			return rel, fmt.Errorf("failed pre-install: %s", err)
+			return rel, fmt.Errorf("failed pre-install: %w", err)
 		}
 	}
 
@@ -496,7 +496,7 @@ func (i *Install) performInstall(rel *release.Release, toBeAdopted kube.Resource
 
 	if !i.DisableHooks {
 		if err := i.cfg.execHook(rel, release.HookPostInstall, i.WaitStrategy, i.Timeout); err != nil {
-			return rel, fmt.Errorf("failed post-install: %s", err)
+			return rel, fmt.Errorf("failed post-install: %w", err)
 		}
 	}
 

pkg/action/package_test.go

@@ -22,6 +22,7 @@ import (
 	"testing"
 
 	"github.com/Masterminds/semver/v3"
+	"github.com/stretchr/testify/require"
 
 	"helm.sh/helm/v4/internal/test/ensure"
 )
@@ -144,10 +145,7 @@ func TestValidateVersion(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			if err := validateVersion(tt.args.ver); err != nil {
-				if err != tt.wantErr {
+				require.ErrorIsf(t, err, tt.wantErr, "Expected {%v}, got {%v}", tt.wantErr, err)
-					t.Errorf("Expected {%v}, got {%v}", tt.wantErr, err)
-				}
-
 			}
 		})
 	}

pkg/action/upgrade.go

@@ -419,7 +419,7 @@ func (u *Upgrade) releasingUpgrade(c chan<- resultMessage, upgradedRelease *rele
 
 	if !u.DisableHooks {
 		if err := u.cfg.execHook(upgradedRelease, release.HookPreUpgrade, u.WaitStrategy, u.Timeout); err != nil {
-			u.reportToPerformUpgrade(c, upgradedRelease, kube.ResourceList{}, fmt.Errorf("pre-upgrade hooks failed: %s", err))
+			u.reportToPerformUpgrade(c, upgradedRelease, kube.ResourceList{}, fmt.Errorf("pre-upgrade hooks failed: %w", err))
 			return
 		}
 	} else {
@@ -456,7 +456,7 @@ func (u *Upgrade) releasingUpgrade(c chan<- resultMessage, upgradedRelease *rele
 	// post-upgrade hooks
 	if !u.DisableHooks {
 		if err := u.cfg.execHook(upgradedRelease, release.HookPostUpgrade, u.WaitStrategy, u.Timeout); err != nil {
-			u.reportToPerformUpgrade(c, upgradedRelease, results.Created, fmt.Errorf("post-upgrade hooks failed: %s", err))
+			u.reportToPerformUpgrade(c, upgradedRelease, results.Created, fmt.Errorf("post-upgrade hooks failed: %w", err))
 			return
 		}
 	}

pkg/action/validate.go

@@ -81,7 +81,7 @@ func existingResourceConflict(resources kube.ResourceList, releaseName, releaseN
 
 		// Allow adoption of the resource if it is managed by Helm and is annotated with correct release name and namespace.
 		if err := checkOwnership(existing, releaseName, releaseNamespace); err != nil {
-			return fmt.Errorf("%s exists and cannot be imported into the current release: %s", resourceString(info), err)
+			return fmt.Errorf("%s exists and cannot be imported into the current release: %w", resourceString(info), err)
 		}
 
 		requireUpdate.Append(info)
@@ -103,13 +103,13 @@ func checkOwnership(obj runtime.Object, releaseName, releaseNamespace string) er
 
 	var errs []error
 	if err := requireValue(lbls, appManagedByLabel, appManagedByHelm); err != nil {
-		errs = append(errs, fmt.Errorf("label validation error: %s", err))
+		errs = append(errs, fmt.Errorf("label validation error: %w", err))
 	}
 	if err := requireValue(annos, helmReleaseNameAnnotation, releaseName); err != nil {
-		errs = append(errs, fmt.Errorf("annotation validation error: %s", err))
+		errs = append(errs, fmt.Errorf("annotation validation error: %w", err))
 	}
 	if err := requireValue(annos, helmReleaseNamespaceAnnotation, releaseNamespace); err != nil {
-		errs = append(errs, fmt.Errorf("annotation validation error: %s", err))
+		errs = append(errs, fmt.Errorf("annotation validation error: %w", err))
 	}
 
 	if len(errs) > 0 {
@@ -141,7 +141,7 @@ func setMetadataVisitor(releaseName, releaseNamespace string, forceOwnership boo
 
 		if !forceOwnership {
 			if err := checkOwnership(info.Object, releaseName, releaseNamespace); err != nil {
-				return fmt.Errorf("%s cannot be owned: %s", resourceString(info), err)
+				return fmt.Errorf("%s cannot be owned: %w", resourceString(info), err)
 			}
 		}
 
@@ -149,7 +149,7 @@ func setMetadataVisitor(releaseName, releaseNamespace string, forceOwnership boo
 			appManagedByLabel: appManagedByHelm,
 		}); err != nil {
 			return fmt.Errorf(
-				"%s labels could not be updated: %s",
+				"%s labels could not be updated: %w",
 				resourceString(info), err,
 			)
 		}
@@ -159,7 +159,7 @@ func setMetadataVisitor(releaseName, releaseNamespace string, forceOwnership boo
 			helmReleaseNamespaceAnnotation: releaseNamespace,
 		}); err != nil {
 			return fmt.Errorf(
-				"%s annotations could not be updated: %s",
+				"%s annotations could not be updated: %w",
 				resourceString(info), err,
 			)
 		}

pkg/chart/v2/loader/archive.go

@@ -72,8 +72,8 @@ func LoadFile(name string) (*chart.Chart, error) {
 
 	c, err := LoadArchive(raw)
 	if err != nil {
-		if err == gzip.ErrHeader {
+		if errors.Is(err, gzip.ErrHeader) {
-			return nil, fmt.Errorf("file '%s' does not appear to be a valid chart file (details: %s)", name, err)
+			return nil, fmt.Errorf("file '%s' does not appear to be a valid chart file (details: %w)", name, err)
 		}
 	}
 	return c, err
@@ -90,8 +90,8 @@ func ensureArchive(name string, raw *os.File) error {
 	// Check the file format to give us a chance to provide the user with more actionable feedback.
 	buffer := make([]byte, 512)
 	_, err := raw.Read(buffer)
-	if err != nil && err != io.EOF {
+	if err != nil && !errors.Is(err, io.EOF) {
-		return fmt.Errorf("file '%s' cannot be read: %s", name, err)
+		return fmt.Errorf("file '%s' cannot be read: %w", name, err)
 	}
 
 	// Helm may identify achieve of the application/x-gzip as application/vnd.ms-fontobject.
@@ -131,7 +131,7 @@ func LoadArchiveFiles(in io.Reader) ([]*BufferedFile, error) {
 	for {
 		b := bytes.NewBuffer(nil)
 		hd, err := tr.Next()
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			break
 		}
 		if err != nil {

pkg/chart/v2/loader/load.go

@@ -218,7 +218,7 @@ func LoadValues(data io.Reader) (map[string]interface{}, error) {
 		currentMap := map[string]interface{}{}
 		raw, err := reader.Read()
 		if err != nil {
-			if err == io.EOF {
+			if errors.Is(err, io.EOF) {
 				break
 			}
 			return nil, fmt.Errorf("error reading yaml document: %w", err)

pkg/chart/v2/metadata_test.go

@@ -17,6 +17,8 @@ package v2
 
 import (
 	"testing"
+
+	"github.com/stretchr/testify/require"
 )
 
 func TestValidate(t *testing.T) {
@@ -181,9 +183,7 @@ func TestValidate(t *testing.T) {
 
 	for _, tt := range tests {
 		result := tt.md.Validate()
-		if result != tt.err {
+		require.ErrorIsf(t, result, tt.err, "expected %q, got %q in test %q", tt.err, result, tt.name)
-			t.Errorf("expected %q, got %q in test %q", tt.err, result, tt.name)
-		}
 	}
 }
 

pkg/chart/v2/util/dependencies.go

@@ -16,6 +16,7 @@ limitations under the License.
 package util
 
 import (
+	"errors"
 	"log/slog"
 	"strings"
 
@@ -42,14 +43,16 @@ func processDependencyConditions(reqs []*chart.Dependency, cvals Values, cpath s
 			if len(c) > 0 {
 				// retrieve value
 				vv, err := cvals.PathValue(cpath + c)
-				if err == nil {
+				var errNoValue ErrNoValue
+				switch {
+				case err == nil:
 					// if not bool, warn
 					if bv, ok := vv.(bool); ok {
 						r.Enabled = bv
 						break
 					}
 					slog.Warn("returned non-bool value", "path", c, "chart", r.Name)
-				} else if _, ok := err.(ErrNoValue); !ok {
+				case !errors.As(err, &errNoValue):
 					// this is a real error
 					slog.Warn("the method PathValue returned error", slog.Any("error", err))
 				}

pkg/chart/v2/util/dependencies_test.go

@@ -21,6 +21,8 @@ import (
 	"strconv"
 	"testing"
 
+	"github.com/stretchr/testify/require"
+
 	chart "helm.sh/helm/v4/pkg/chart/v2"
 	"helm.sh/helm/v4/pkg/chart/v2/loader"
 )
@@ -250,12 +252,8 @@ func TestProcessDependencyImportValues(t *testing.T) {
 	if err == nil {
 		t.Error("expect nil value not found but found it")
 	}
-	switch xerr := err.(type) {
+	var xerr ErrNoValue
-	case ErrNoValue:
+	require.ErrorAs(t, err, &xerr, "expected an ErrNoValue but got %q instead", err)
-		// We found what we expected
-	default:
-		t.Errorf("expected an ErrNoValue but got %q instead", xerr)
-	}
 
 	c = loadChart(t, "testdata/subpop")
 	if err := processDependencyImportValues(c, true); err != nil {
@@ -458,7 +456,6 @@ func TestDependentChartAliases(t *testing.T) {
 	if aliasChart := getAliasDependency(c.Dependencies(), req[2]); aliasChart != nil {
 		t.Fatalf("expected no chart but got %s", aliasChart.Name())
 	}
-
 }
 
 func TestDependentChartWithSubChartsAbsentInDependency(t *testing.T) {

pkg/cmd/dependency_build.go

@@ -16,6 +16,7 @@ limitations under the License.
 package cmd
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -75,7 +76,8 @@ func newDependencyBuildCmd(out io.Writer) *cobra.Command {
 				man.Verify = downloader.VerifyIfPossible
 			}
 			err = man.Build()
-			if e, ok := err.(downloader.ErrRepoNotFound); ok {
+			var e downloader.ErrRepoNotFound
+			if errors.As(err, &e) {
 				return fmt.Errorf("%s. Please add the missing repos via 'helm repo add'", e.Error())
 			}
 			return err

pkg/cmd/dependency_update_test.go

@@ -16,7 +16,6 @@ limitations under the License.
 package cmd
 
 import (
-	"errors"
 	"fmt"
 	"io/fs"
 	"os"
@@ -24,6 +23,8 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/stretchr/testify/require"
+
 	"helm.sh/helm/v4/internal/test/ensure"
 	chart "helm.sh/helm/v4/pkg/chart/v2"
 	chartutil "helm.sh/helm/v4/pkg/chart/v2/util"
@@ -204,9 +205,8 @@ func TestDependencyUpdateCmd_DoNotDeleteOldChartsOnError(t *testing.T) {
 
 	// Make sure tmpcharts-x is deleted
 	tmpPath := filepath.Join(dir(chartname), fmt.Sprintf("tmpcharts-%d", os.Getpid()))
-	if _, err := os.Stat(tmpPath); !errors.Is(err, fs.ErrNotExist) {
+	_, err = os.Stat(tmpPath)
-		t.Fatalf("tmpcharts dir still exists")
+	require.ErrorIsf(t, err, fs.ErrNotExist, "tmpcharts dir still exists")
-	}
 }
 
 func TestDependencyUpdateCmd_WithRepoThatWasNotAdded(t *testing.T) {

pkg/cmd/lint.go

@@ -60,7 +60,7 @@ func newLintCmd(out io.Writer) *cobra.Command {
 			if kubeVersion != "" {
 				parsedKubeVersion, err := chartutil.ParseKubeVersion(kubeVersion)
 				if err != nil {
-					return fmt.Errorf("invalid kube version '%s': %s", kubeVersion, err)
+					return fmt.Errorf("invalid kube version '%s': %w", kubeVersion, err)
 				}
 				client.KubeVersion = parsedKubeVersion
 			}

pkg/cmd/load_plugins.go

@@ -17,6 +17,7 @@ package cmd
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"io"
 	"log"
@@ -134,7 +135,8 @@ func callPluginExecutable(pluginName string, main string, argv []string, out io.
 	prog.Stdout = out
 	prog.Stderr = os.Stderr
 	if err := prog.Run(); err != nil {
-		if eerr, ok := err.(*exec.ExitError); ok {
+		var eerr *exec.ExitError
+		if errors.As(err, &eerr) {
 			os.Stderr.Write(eerr.Stderr)
 			status := eerr.Sys().(syscall.WaitStatus)
 			return PluginError{

pkg/cmd/plugin.go

@@ -16,6 +16,7 @@ limitations under the License.
 package cmd
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"log/slog"
@@ -71,7 +72,8 @@ func runHook(p *plugin.Plugin, event string) error {
 
 	prog.Stdout, prog.Stderr = os.Stdout, os.Stderr
 	if err := prog.Run(); err != nil {
-		if eerr, ok := err.(*exec.ExitError); ok {
+		var eerr *exec.ExitError
+		if errors.As(err, &eerr) {
 			os.Stderr.Write(eerr.Stderr)
 			return fmt.Errorf("plugin %s hook for %q exited with error", event, p.Metadata.Name)
 		}

pkg/cmd/plugin_test.go

@@ -25,6 +25,7 @@ import (
 
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
+	"github.com/stretchr/testify/require"
 
 	release "helm.sh/helm/v4/pkg/release/v1"
 )
@@ -142,10 +143,8 @@ func TestLoadPlugins(t *testing.T) {
 		if runtime.GOOS != "windows" {
 			if err := pp.RunE(pp, tt.args); err != nil {
 				if tt.code > 0 {
-					perr, ok := err.(PluginError)
+					var perr PluginError
-					if !ok {
+					require.ErrorAs(t, err, &perr, "Expected %s to return pluginError: got %v(%T)", tt.use, err, err)
-						t.Errorf("Expected %s to return pluginError: got %v(%T)", tt.use, err, err)
-					}
 					if perr.Code != tt.code {
 						t.Errorf("Expected %s to return %d: got %d", tt.use, tt.code, perr.Code)
 					}
@@ -217,10 +216,8 @@ func TestLoadPluginsWithSpace(t *testing.T) {
 		if runtime.GOOS != "windows" {
 			if err := pp.RunE(pp, tt.args); err != nil {
 				if tt.code > 0 {
-					perr, ok := err.(PluginError)
+					var perr PluginError
-					if !ok {
+					require.ErrorAs(t, err, &perr, "Expected %s to return pluginError: got %v(%T)", tt.use, err, err)
-						t.Errorf("Expected %s to return pluginError: got %v(%T)", tt.use, err, err)
-					}
 					if perr.Code != tt.code {
 						t.Errorf("Expected %s to return %d: got %d", tt.use, tt.code, perr.Code)
 					}

pkg/cmd/plugin_uninstall.go

@@ -69,7 +69,7 @@ func (o *pluginUninstallOptions) run(out io.Writer) error {
 	for _, name := range o.names {
 		if found := findPlugin(plugins, name); found != nil {
 			if err := uninstallPlugin(found); err != nil {
-				errorPlugins = append(errorPlugins, fmt.Errorf("failed to uninstall plugin %s, got error (%v)", name, err))
+				errorPlugins = append(errorPlugins, fmt.Errorf("failed to uninstall plugin %s, got error (%w)", name, err))
 			} else {
 				fmt.Fprintf(out, "Uninstalled plugin: %s\n", name)
 			}

pkg/cmd/plugin_update.go

@@ -72,7 +72,7 @@ func (o *pluginUpdateOptions) run(out io.Writer) error {
 	for _, name := range o.names {
 		if found := findPlugin(plugins, name); found != nil {
 			if err := updatePlugin(found); err != nil {
-				errorPlugins = append(errorPlugins, fmt.Errorf("failed to update plugin %s, got error (%v)", name, err))
+				errorPlugins = append(errorPlugins, fmt.Errorf("failed to update plugin %s, got error (%w)", name, err))
 			} else {
 				fmt.Fprintf(out, "Updated plugin: %s\n", name)
 			}

pkg/cmd/rollback.go

@@ -61,7 +61,7 @@ func newRollbackCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 			if len(args) > 1 {
 				ver, err := strconv.Atoi(args[1])
 				if err != nil {
-					return fmt.Errorf("could not convert revision to a number: %v", err)
+					return fmt.Errorf("could not convert revision to a number: %w", err)
 				}
 				client.Version = ver
 			}

pkg/cmd/search_hub.go

@@ -141,7 +141,7 @@ func (h *hubSearchWriter) WriteTable(out io.Writer) error {
 
 		_, err := out.Write([]byte("No results found\n"))
 		if err != nil {
-			return fmt.Errorf("unable to write results: %s", err)
+			return fmt.Errorf("unable to write results: %w", err)
 		}
 		return nil
 	}

pkg/cmd/search_repo.go

@@ -221,7 +221,7 @@ func (r *repoSearchWriter) WriteTable(out io.Writer) error {
 
 		_, err := out.Write([]byte("No results found\n"))
 		if err != nil {
-			return fmt.Errorf("unable to write results: %s", err)
+			return fmt.Errorf("unable to write results: %w", err)
 		}
 		return nil
 	}

pkg/cmd/template.go

@@ -71,7 +71,7 @@ func newTemplateCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 			if kubeVersion != "" {
 				parsedKubeVersion, err := chartutil.ParseKubeVersion(kubeVersion)
 				if err != nil {
-					return fmt.Errorf("invalid kube version '%s': %s", kubeVersion, err)
+					return fmt.Errorf("invalid kube version '%s': %w", kubeVersion, err)
 				}
 				client.KubeVersion = parsedKubeVersion
 			}

pkg/cmd/upgrade.go

@@ -18,6 +18,7 @@ package cmd
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"log"
@@ -122,7 +123,7 @@ func newUpgradeCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 				histClient := action.NewHistory(cfg)
 				histClient.Max = 1
 				versions, err := histClient.Run(args[0])
-				if err == driver.ErrReleaseNotFound || isReleaseUninstalled(versions) {
+				if errors.Is(err, driver.ErrReleaseNotFound) || isReleaseUninstalled(versions) {
 					// Only print this to stdout for table output
 					if outfmt == output.Table {
 						fmt.Fprintf(out, "Release %q does not exist. Installing it now.\n", args[0])

pkg/downloader/chart_downloader.go

@@ -187,7 +187,7 @@ func (c *ChartDownloader) ResolveChartVersion(ref, version string) (*url.URL, er
 		if err != nil {
 			// If there is no special config, return the default HTTP client and
 			// swallow the error.
-			if err == ErrNoOwnerRepo {
+			if errors.Is(err, ErrNoOwnerRepo) {
 				// Make sure to add the ref URL as the URL for the getter
 				c.Options = append(c.Options, getter.WithURL(ref))
 				return u, nil

pkg/downloader/chart_downloader_test.go

@@ -20,6 +20,8 @@ import (
 	"path/filepath"
 	"testing"
 
+	"github.com/stretchr/testify/require"
+
 	"helm.sh/helm/v4/internal/test/ensure"
 	"helm.sh/helm/v4/pkg/cli"
 	"helm.sh/helm/v4/pkg/getter"
@@ -362,7 +364,6 @@ func TestScanReposForURL(t *testing.T) {
 
 	// A lookup failure should produce an ErrNoOwnerRepo
 	u = "https://no.such.repo/foo/bar-1.23.4.tgz"
-	if _, err = c.scanReposForURL(u, rf); err != ErrNoOwnerRepo {
+	_, err = c.scanReposForURL(u, rf)
-		t.Fatalf("expected ErrNoOwnerRepo, got %v", err)
+	require.ErrorIs(t, err, ErrNoOwnerRepo, "expected ErrNoOwnerRepo, got %v", err)
-	}
 }

pkg/downloader/manager.go

@@ -258,7 +258,7 @@ func (m *Manager) downloadAll(deps []*chart.Dependency) error {
 			return err
 		}
 	} else {
-		return fmt.Errorf("unable to retrieve file info for '%s': %v", destPath, err)
+		return fmt.Errorf("unable to retrieve file info for '%s': %w", destPath, err)
 	}
 
 	// Prepare tmpPath
@@ -278,17 +278,17 @@ func (m *Manager) downloadAll(deps []*chart.Dependency) error {
 			chartPath := filepath.Join(destPath, dep.Name)
 			ch, err := loader.LoadDir(chartPath)
 			if err != nil {
-				return fmt.Errorf("unable to load chart '%s': %v", chartPath, err)
+				return fmt.Errorf("unable to load chart '%s': %w", chartPath, err)
 			}
 
 			constraint, err := semver.NewConstraint(dep.Version)
 			if err != nil {
-				return fmt.Errorf("dependency %s has an invalid version/constraint format: %s", dep.Name, err)
+				return fmt.Errorf("dependency %s has an invalid version/constraint format: %w", dep.Name, err)
 			}
 
 			v, err := semver.NewVersion(ch.Metadata.Version)
 			if err != nil {
-				return fmt.Errorf("invalid version %s for dependency %s: %s", dep.Version, dep.Name, err)
+				return fmt.Errorf("invalid version %s for dependency %s: %w", dep.Version, dep.Name, err)
 			}
 
 			if !constraint.Check(v) {

pkg/engine/engine.go

@@ -129,9 +129,11 @@ type renderable struct {
 	basePath string
 }
 
-const warnStartDelim = "HELM_ERR_START"
+const (
-const warnEndDelim = "HELM_ERR_END"
+	warnStartDelim   = "HELM_ERR_START"
-const recursionMaxNums = 1000
+	warnEndDelim     = "HELM_ERR_END"
+	recursionMaxNums = 1000
+)
 
 var warnRegex = regexp.MustCompile(warnStartDelim + `((?s).*)` + warnEndDelim)
 
@@ -331,7 +333,7 @@ func cleanupParseError(filename string, err error) error {
 	tokens := strings.Split(err.Error(), ": ")
 	if len(tokens) == 1 {
 		// This might happen if a non-templating error occurs
-		return fmt.Errorf("parse error in (%s): %s", filename, err)
+		return fmt.Errorf("parse error in (%s): %w", filename, err)
 	}
 	// The first token is "template"
 	// The second token is either "filename:lineno" or "filename:lineNo:columnNo"
@@ -368,14 +370,15 @@ func reformatExecErrorMsg(filename string, err error) error {
 	// If the regex's can parse out details from that error message such as the line number, template it failed on,
 	// and error description, then it will construct a new error that displays these details in a structured way.
 	// If there are issues with parsing the error message, the err passed into the function should return instead.
-	if _, isExecError := err.(template.ExecError); !isExecError {
+	var execErr template.ExecError
+	if !errors.As(err, &execErr) {
 		return err
 	}
 
 	tokens := strings.SplitN(err.Error(), ": ", 3)
 	if len(tokens) != 3 {
 		// This might happen if a non-templating error occurs
-		return fmt.Errorf("execution error in (%s): %s", filename, err)
+		return fmt.Errorf("execution error in (%s): %w", filename, err)
 	}
 
 	// The first token is "template"

pkg/engine/engine_test.go

@@ -25,7 +25,6 @@ import (
 	"text/template"
 
 	"github.com/stretchr/testify/assert"
-
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
@@ -646,7 +645,6 @@ func TestRenderDependency(t *testing.T) {
 	if out["outerchart/templates/outer"] != expect {
 		t.Errorf("Expected %q, got %q", expect, out["outer"])
 	}
-
 }
 
 func TestRenderNestedValues(t *testing.T) {
@@ -800,7 +798,6 @@ func TestRenderBuiltinValues(t *testing.T) {
 			t.Errorf("Expected %q, got %q", expect, out[file])
 		}
 	}
-
 }
 
 func TestAlterFuncMap_include(t *testing.T) {
@@ -993,7 +990,6 @@ func TestAlterFuncMap_tplinclude(t *testing.T) {
 	if got := out["TplFunction/templates/base"]; got != expect {
 		t.Errorf("Expected %q, got %q (%v)", expect, got, out)
 	}
-
 }
 
 func TestRenderRecursionLimit(t *testing.T) {
@@ -1048,7 +1044,6 @@ func TestRenderRecursionLimit(t *testing.T) {
 	if got := out["overlook/templates/quote"]; got != expect {
 		t.Errorf("Expected %q, got %q (%v)", expect, got, out)
 	}
-
 }
 
 func TestRenderLoadTemplateForTplFromFile(t *testing.T) {

pkg/getter/plugingetter.go

@@ -17,6 +17,7 @@ package getter
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"os"
 	"os/exec"
@@ -82,7 +83,8 @@ func (p *pluginGetter) Get(href string, options ...Option) (*bytes.Buffer, error
 	prog.Stdout = buf
 	prog.Stderr = os.Stderr
 	if err := prog.Run(); err != nil {
-		if eerr, ok := err.(*exec.ExitError); ok {
+		var eerr *exec.ExitError
+		if errors.As(err, &eerr) {
 			os.Stderr.Write(eerr.Stderr)
 			return nil, fmt.Errorf("plugin %q exited with error", p.command)
 		}

pkg/kube/client.go

@@ -180,7 +180,7 @@ func (c *Client) getKubeClient() (kubernetes.Interface, error) {
 // IsReachable tests connectivity to the cluster.
 func (c *Client) IsReachable() error {
 	client, err := c.getKubeClient()
-	if err == genericclioptions.ErrEmptyConfig {
+	if errors.Is(err, genericclioptions.ErrEmptyConfig) {
 		// re-replace kubernetes ErrEmptyConfig error with a friendly error
 		// moar workarounds for Kubernetes API breaking.
 		return errors.New("kubernetes cluster unreachable")
@@ -720,7 +720,7 @@ func updateResource(_ *Client, target *resource.Info, currentObj runtime.Object,
 func (c *Client) GetPodList(namespace string, listOptions metav1.ListOptions) (*v1.PodList, error) {
 	podList, err := c.kubeClient.CoreV1().Pods(namespace).List(context.Background(), listOptions)
 	if err != nil {
-		return nil, fmt.Errorf("failed to get pod list with options: %+v with error: %v", listOptions, err)
+		return nil, fmt.Errorf("failed to get pod list with options: %+v with error: %w", listOptions, err)
 	}
 	return podList, nil
 }

pkg/kube/wait.go

@@ -103,7 +103,8 @@ func (hw *legacyWaiter) isRetryableError(err error, resource *resource.Info) boo
 		return false
 	}
 	slog.Debug("error received when checking resource status", "resource", resource.Name, slog.Any("error", err))
-	if ev, ok := err.(*apierrors.StatusError); ok {
+	var ev *apierrors.StatusError
+	if errors.As(err, &ev) {
 		statusCode := ev.Status().Code
 		retryable := hw.isRetryableHTTPStatusCode(statusCode)
 		slog.Debug("status code received", "resource", resource.Name, "statusCode", statusCode, "retryable", retryable)

pkg/lint/rules/chartfile.go

@@ -152,7 +152,7 @@ func validateChartVersion(cf *chart.Metadata) error {
 	valid, msg := c.Validate(version)
 
 	if !valid && len(msg) > 0 {
-		return fmt.Errorf("version %v", msg[0])
+		return fmt.Errorf("version %w", msg[0])
 	}
 
 	return nil

pkg/lint/rules/crds.go

@@ -70,7 +70,7 @@ func Crds(linter *support.Linter) {
 			var yamlStruct *k8sYamlStruct
 
 			err := decoder.Decode(&yamlStruct)
-			if err == io.EOF {
+			if errors.Is(err, io.EOF) {
 				break
 			}
 

pkg/lint/rules/deprecations_test.go

@@ -16,7 +16,11 @@ limitations under the License.
 
 package rules // import "helm.sh/helm/v4/pkg/lint/rules"
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
 
 func TestValidateNoDeprecations(t *testing.T) {
 	deprecated := &k8sYamlStruct{
@@ -27,7 +31,8 @@ func TestValidateNoDeprecations(t *testing.T) {
 	if err == nil {
 		t.Fatal("Expected deprecated extension to be flagged")
 	}
-	depErr := err.(deprecatedAPIError)
+	var depErr deprecatedAPIError
+	require.ErrorAs(t, err, &depErr)
 	if depErr.Message == "" {
 		t.Fatalf("Expected error message to be non-blank: %v", err)
 	}

pkg/lint/rules/template.go

@@ -148,7 +148,7 @@ func TemplatesWithSkipSchemaValidation(linter *support.Linter, values map[string
 				var yamlStruct *k8sYamlStruct
 
 				err := decoder.Decode(&yamlStruct)
-				if err == io.EOF {
+				if errors.Is(err, io.EOF) {
 					break
 				}
 

pkg/lint/rules/template_test.go

@@ -23,6 +23,8 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/stretchr/testify/require"
+
 	chart "helm.sh/helm/v4/pkg/chart/v2"
 	chartutil "helm.sh/helm/v4/pkg/chart/v2/util"
 	"helm.sh/helm/v4/pkg/lint/support"
@@ -215,7 +217,8 @@ func TestDeprecatedAPIFails(t *testing.T) {
 		t.Fatalf("Expected 1 lint error, got %d", l)
 	}
 
-	err := linter.Messages[0].Err.(deprecatedAPIError)
+	var err deprecatedAPIError
+	require.ErrorAs(t, linter.Messages[0].Err, &err)
 	if err.Deprecated != "apps/v1beta1 Deployment" {
 		t.Errorf("Surprised to learn that %q is deprecated", err.Deprecated)
 	}

pkg/plugin/installer/http_installer.go

@@ -234,7 +234,7 @@ func (g *TarGzExtractor) Extract(buffer *bytes.Buffer, targetDir string) error {
 	tarReader := tar.NewReader(uncompressedStream)
 	for {
 		header, err := tarReader.Next()
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			break
 		}
 		if err != nil {

pkg/plugin/installer/local_installer_test.go

@@ -20,6 +20,8 @@ import (
 	"path/filepath"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
+
 	"helm.sh/helm/v4/internal/test/ensure"
 	"helm.sh/helm/v4/pkg/helmpath"
 )
@@ -61,7 +63,5 @@ func TestLocalInstallerNotAFolder(t *testing.T) {
 	if err == nil {
 		t.Fatal("expected error")
 	}
-	if err != ErrPluginNotAFolder {
+	assert.ErrorIs(t, err, ErrPluginNotAFolder, "expected error to equal: %q", err)
-		t.Fatalf("expected error to equal: %q", err)
-	}
 }

pkg/provenance/sign_test.go

@@ -17,6 +17,7 @@ package provenance
 
 import (
 	"crypto"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -323,8 +324,9 @@ func TestVerify(t *testing.T) {
 		t.Errorf("Expected %s to fail.", testTamperedSigBlock)
 	}
 
-	switch err.(type) {
+	var errCase0 pgperrors.SignatureError
-	case pgperrors.SignatureError:
+	switch {
+	case errors.As(err, &errCase0):
 		t.Logf("Tampered sig block error: %s (%T)", err, err)
 	default:
 		t.Errorf("Expected invalid signature error, got %q (%T)", err, err)

pkg/registry/transport.go

@@ -18,6 +18,7 @@ package registry
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"io"
 	"log/slog"
@@ -137,7 +138,7 @@ func logResponseBody(resp *http.Response) string {
 		Closer: body,
 	}
 	// read the body up to limit+1 to check if the body exceeds the limit
-	if _, err := io.CopyN(buf, body, payloadSizeLimit+1); err != nil && err != io.EOF {
+	if _, err := io.CopyN(buf, body, payloadSizeLimit+1); err != nil && !errors.Is(err, io.EOF) {
 		return fmt.Sprintf("   Error reading response body: %v", err)
 	}
 

pkg/registry/util.go

@@ -102,7 +102,7 @@ func NewRegistryClientWithTLS(out io.Writer, certFile, keyFile, caFile string, i
 		tlsutil.WithCAFile(caFile),
 	)
 	if err != nil {
-		return nil, fmt.Errorf("can't create TLS config for client: %s", err)
+		return nil, fmt.Errorf("can't create TLS config for client: %w", err)
 	}
 	// Create a new registry client
 	registryClient, err := NewClient(

pkg/repo/chartrepo_test.go

@@ -18,7 +18,6 @@ package repo
 
 import (
 	"bytes"
-	"errors"
 	"net/http"
 	"net/http/httptest"
 	"os"
@@ -27,6 +26,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/require"
 	"sigs.k8s.io/yaml"
 
 	"helm.sh/helm/v4/pkg/cli"
@@ -203,9 +203,7 @@ func TestErrorFindChartInRepoURL(t *testing.T) {
 	} else if err.Error() != `chart "nginx1" not found in `+srv.URL+` repository` {
 		t.Errorf("Expected error for chart not found, but got a different error (%v)", err)
 	}
-	if !errors.Is(err, ChartNotFoundError{}) {
+	require.ErrorIsf(t, err, ChartNotFoundError{}, "error is not of correct error type structure")
-		t.Errorf("error is not of correct error type structure")
-	}
 
 	if _, err = FindChartInRepoURL(srv.URL, "nginx1", g, WithChartVersion("0.1.0")); err == nil {
 		t.Errorf("Expected error for chart not found, but did not get any errors")

pkg/repo/index.go

@@ -401,8 +401,8 @@ func jsonOrYamlUnmarshal(b []byte, i interface{}) error {
 // And repository indexes may be generated by older/non-compliant software, which doesn't
 // conform to all validations.
 func ignoreSkippableChartValidationError(err error) error {
-	verr, ok := err.(chart.ValidationError)
+	var verr chart.ValidationError
-	if !ok {
+	if !errors.As(err, &verr) {
 		return err
 	}
 

pkg/repo/index_test.go

@@ -28,6 +28,8 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/stretchr/testify/require"
+
 	chart "helm.sh/helm/v4/pkg/chart/v2"
 	"helm.sh/helm/v4/pkg/cli"
 	"helm.sh/helm/v4/pkg/getter"
@@ -639,10 +641,7 @@ func TestIgnoreSkippableChartValidationError(t *testing.T) {
 				return
 			}
 
-			if tc.Input != result {
+			require.ErrorIs(t, tc.Input, result, "expected the result equal to input")
-				t.Error("expected the result equal to input")
-			}
-
 		})
 	}
 }

pkg/storage/driver/cfgmaps_test.go

@@ -16,10 +16,11 @@ package driver
 import (
 	"encoding/base64"
 	"encoding/json"
-	"errors"
 	"reflect"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	v1 "k8s.io/api/core/v1"
 
 	rspb "helm.sh/helm/v4/pkg/release/v1"
@@ -160,9 +161,7 @@ func TestConfigMapQuery(t *testing.T) {
 	}
 
 	_, err = cfgmaps.Query(map[string]string{"name": "notExist"})
-	if err != ErrReleaseNotFound {
+	assert.ErrorIsf(t, err, ErrReleaseNotFound, "Expected {%v}, got {%v}", ErrReleaseNotFound, err)
-		t.Errorf("Expected {%v}, got {%v}", ErrReleaseNotFound, err)
-	}
 }
 
 func TestConfigMapCreate(t *testing.T) {
@@ -231,9 +230,7 @@ func TestConfigMapDelete(t *testing.T) {
 
 	// perform the delete on a non-existent release
 	_, err := cfgmaps.Delete("nonexistent")
-	if err != ErrReleaseNotFound {
+	require.ErrorIsf(t, err, ErrReleaseNotFound, "Expected ErrReleaseNotFound: got {%v}", err)
-		t.Fatalf("Expected ErrReleaseNotFound: got {%v}", err)
-	}
 
 	// perform the delete
 	rls, err := cfgmaps.Delete(key)
@@ -244,7 +241,5 @@ func TestConfigMapDelete(t *testing.T) {
 		t.Errorf("Expected {%v}, got {%v}", rel, rls)
 	}
 	_, err = cfgmaps.Get(key)
-	if !errors.Is(err, ErrReleaseNotFound) {
+	require.ErrorIsf(t, err, ErrReleaseNotFound, "Expected {%v}, got {%v}", ErrReleaseNotFound, err)
-		t.Errorf("Expected {%v}, got {%v}", ErrReleaseNotFound, err)
-	}
 }

pkg/storage/driver/secrets_test.go

@@ -16,10 +16,11 @@ package driver
 import (
 	"encoding/base64"
 	"encoding/json"
-	"errors"
 	"reflect"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	v1 "k8s.io/api/core/v1"
 
 	rspb "helm.sh/helm/v4/pkg/release/v1"
@@ -160,9 +161,7 @@ func TestSecretQuery(t *testing.T) {
 	}
 
 	_, err = secrets.Query(map[string]string{"name": "notExist"})
-	if err != ErrReleaseNotFound {
+	assert.ErrorIsf(t, err, ErrReleaseNotFound, "Expected {%v}, got {%v}", ErrReleaseNotFound, err)
-		t.Errorf("Expected {%v}, got {%v}", ErrReleaseNotFound, err)
-	}
 }
 
 func TestSecretCreate(t *testing.T) {
@@ -231,9 +230,7 @@ func TestSecretDelete(t *testing.T) {
 
 	// perform the delete on a non-existing release
 	_, err := secrets.Delete("nonexistent")
-	if err != ErrReleaseNotFound {
+	require.ErrorIsf(t, err, ErrReleaseNotFound, "Expected ErrReleaseNotFound, got: {%v}", err)
-		t.Fatalf("Expected ErrReleaseNotFound, got: {%v}", err)
-	}
 
 	// perform the delete
 	rls, err := secrets.Delete(key)
@@ -244,7 +241,5 @@ func TestSecretDelete(t *testing.T) {
 		t.Errorf("Expected {%v}, got {%v}", rel, rls)
 	}
 	_, err = secrets.Get(key)
-	if !errors.Is(err, ErrReleaseNotFound) {
+	require.ErrorIsf(t, err, ErrReleaseNotFound, "Expected {%v}, got {%v}", ErrReleaseNotFound, err)
-		t.Errorf("Expected {%v}, got {%v}", ErrReleaseNotFound, err)
-	}
 }

pkg/storage/driver/sql.go

@@ -460,7 +460,7 @@ func (s *SQL) Create(key string, rls *rspb.Release) error {
 	transaction, err := s.db.Beginx()
 	if err != nil {
 		slog.Debug("failed to start SQL transaction", slog.Any("error", err))
-		return fmt.Errorf("error beginning transaction: %v", err)
+		return fmt.Errorf("error beginning transaction: %w", err)
 	}
 
 	insertQuery, args, err := s.statementBuilder.
@@ -594,7 +594,7 @@ func (s *SQL) Delete(key string) (*rspb.Release, error) {
 	transaction, err := s.db.Beginx()
 	if err != nil {
 		slog.Debug("failed to start SQL transaction", slog.Any("error", err))
-		return nil, fmt.Errorf("error beginning transaction: %v", err)
+		return nil, fmt.Errorf("error beginning transaction: %w", err)
 	}
 
 	selectQuery, args, err := s.statementBuilder.

pkg/storage/driver/sql_test.go

@@ -22,6 +22,7 @@ import (
 
 	sqlmock "github.com/DATA-DOG/go-sqlmock"
 	migrate "github.com/rubenv/sql-migrate"
+	"github.com/stretchr/testify/require"
 
 	rspb "helm.sh/helm/v4/pkg/release/v1"
 )
@@ -412,11 +413,7 @@ func TestSqlQuery(t *testing.T) {
 	mockGetReleaseCustomLabels(mock, "", deployedRelease.Namespace, deployedRelease.Labels)
 
 	_, err := sqlDriver.Query(labelSetUnknown)
-	if err == nil {
+	require.ErrorIsf(t, err, ErrReleaseNotFound, "failed to query for unknown smug-pigeon release: %v", err)
-		t.Errorf("Expected error {%v}, got nil", ErrReleaseNotFound)
-	} else if err != ErrReleaseNotFound {
-		t.Fatalf("failed to query for unknown smug-pigeon release: %v", err)
-	}
 
 	results, err := sqlDriver.Query(labelSetDeployed)
 	if err != nil {

pkg/storage/storage_test.go

@@ -22,6 +22,8 @@ import (
 	"reflect"
 	"testing"
 
+	"github.com/stretchr/testify/require"
+
 	rspb "helm.sh/helm/v4/pkg/release/v1"
 	"helm.sh/helm/v4/pkg/storage/driver"
 )
@@ -329,9 +331,7 @@ func TestMaxHistoryErrorHandling(t *testing.T) {
 	rls2 := ReleaseTestData{Name: name, Version: 2, Status: rspb.StatusSuperseded}.ToRelease()
 	wantErr := errMaxHistoryMockDriverSomethingHappened
 	gotErr := storage.Create(rls2)
-	if !errors.Is(gotErr, wantErr) {
+	require.ErrorIsf(t, gotErr, wantErr, "Storing release 'angry-bird' (v2) should return the error %#v, but returned %#v", wantErr, gotErr)
-		t.Fatalf("Storing release 'angry-bird' (v2) should return the error %#v, but returned %#v", wantErr, gotErr)
-	}
 }
 
 func TestStorageRemoveLeastRecent(t *testing.T) {

pkg/strvals/literal_parser.go

@@ -17,6 +17,7 @@ package strvals
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"io"
 	"strconv"
@@ -66,7 +67,7 @@ func (t *literalParser) parse() error {
 		if err == nil {
 			continue
 		}
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			return nil
 		}
 		return err
@@ -105,7 +106,7 @@ func (t *literalParser) key(data map[string]interface{}, nestedNameLevel int) (r
 		case lastRune == '=':
 			// found end of key: swallow the '=' and get the value
 			value, err := t.val()
-			if err == nil && err != io.EOF {
+			if err == nil && !errors.Is(err, io.EOF) {
 				return err
 			}
 			set(data, string(key), string(value))
@@ -183,7 +184,7 @@ func (t *literalParser) listItem(list []interface{}, i, nestedNameLevel int) ([]
 
 	case lastRune == '=':
 		value, err := t.val()
-		if err != nil && err != io.EOF {
+		if err != nil && !errors.Is(err, io.EOF) {
 			return list, err
 		}
 		return setIndex(list, i, string(value))

pkg/strvals/parser.go

@@ -161,7 +161,7 @@ func (t *parser) parse() error {
 		if err == nil {
 			continue
 		}
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			return nil
 		}
 		return err
@@ -240,16 +240,16 @@ func (t *parser) key(data map[string]interface{}, nestedNameLevel int) (reterr e
 			// End of key. Consume =, Get value.
 			// FIXME: Get value list first
 			vl, e := t.valList()
-			switch e {
+			switch {
-			case nil:
+			case e == nil:
 				set(data, string(k), vl)
 				return nil
-			case io.EOF:
+			case errors.Is(e, io.EOF):
 				set(data, string(k), "")
 				return e
-			case ErrNotList:
+			case errors.Is(e, ErrNotList):
 				rs, e := t.val()
-				if e != nil && e != io.EOF {
+				if e != nil && !errors.Is(e, io.EOF) {
 					return e
 				}
 				v, e := t.reader(rs)
@@ -330,7 +330,6 @@ func (t *parser) keyIndex() (int, error) {
 	}
 	// v should be the index
 	return strconv.Atoi(string(v))
-
 }
 
 func (t *parser) listItem(list []interface{}, i, nestedNameLevel int) ([]interface{}, error) {
@@ -373,14 +372,14 @@ func (t *parser) listItem(list []interface{}, i, nestedNameLevel int) ([]interfa
 			return list, err
 		}
 		vl, e := t.valList()
-		switch e {
+		switch {
-		case nil:
+		case e == nil:
 			return setIndex(list, i, vl)
-		case io.EOF:
+		case errors.Is(e, io.EOF):
 			return setIndex(list, i, "")
-		case ErrNotList:
+		case errors.Is(e, ErrNotList):
 			rs, e := t.val()
-			if e != nil && e != io.EOF {
+			if e != nil && !errors.Is(e, io.EOF) {
 				return list, e
 			}
 			v, e := t.reader(rs)
@@ -479,7 +478,7 @@ func (t *parser) valList() ([]interface{}, error) {
 	for {
 		switch rs, last, err := runesUntil(t.sc, stop); {
 		case err != nil:
-			if err == io.EOF {
+			if errors.Is(err, io.EOF) {
 				err = errors.New("list must terminate with '}'")
 			}
 			return list, err