Fix various lints

cmd/krane/go.mod

@@ -1,6 +1,6 @@
 module github.com/google/go-containerregistry/cmd/krane
 
-go 1.17
+go 1.18
 
 replace github.com/google/go-containerregistry => ../../
 

go.mod

@@ -1,6 +1,6 @@
 module github.com/google/go-containerregistry
 
-go 1.17
+go 1.18
 
 require (
 	github.com/containerd/stargz-snapshotter/estargz v0.12.1

internal/cmd/edit.go

@@ -139,7 +139,7 @@ func interactive(in io.Reader, out io.Writer) bool {
 	return interactiveFile(in) && interactiveFile(out)
 }
 
-func interactiveFile(i interface{}) bool {
+func interactiveFile(i any) bool {
 	f, ok := i.(*os.File)
 	if !ok {
 		return false

internal/compression/compression.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package compression abstracts over gzip and zstd.
 package compression
 
 import (
@@ -24,6 +25,7 @@ import (
 	"github.com/google/go-containerregistry/pkg/compression"
 )
 
+// Opener represents e.g. opening a file.
 type Opener = func() (io.ReadCloser, error)
 
 // GetCompression detects whether an Opener is compressed and which algorithm is used.
@@ -76,9 +78,9 @@ type PeekReader interface {
 func intoPeekReader(r io.Reader) PeekReader {
 	if p, ok := r.(PeekReader); ok {
 		return p
-	} else {
-		return bufio.NewReader(r)
 	}
+
+	return bufio.NewReader(r)
 }
 
 // CheckHeader checks whether the first bytes from a PeekReader match an expected header

internal/compression/compression_test.go

@@ -37,7 +37,6 @@ func testPeekCompression(t *testing.T,
 
 	compressed := compress(io.NopCloser(contentBuf))
 	compressionDetected, pr, err := PeekCompression(compressed)
-
 	if err != nil {
 		t.Error("PeekCompression() =", err)
 	}
@@ -47,6 +46,9 @@ func testPeekCompression(t *testing.T,
 	}
 
 	decompressed, err := decompress(withCloser(pr, compressed))
+	if err != nil {
+		t.Fatal(err)
+	}
 
 	b, err := io.ReadAll(decompressed)
 	if err != nil {

internal/gzip/zip.go

@@ -24,6 +24,7 @@ import (
 	"github.com/google/go-containerregistry/internal/and"
 )
 
+// MagicHeader is the start of gzip files.
 var MagicHeader = []byte{'\x1f', '\x8b'}
 
 // ReadCloser reads uncompressed input data from the io.ReadCloser and

internal/zstd/zstd.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package zstd provides helper functions for interacting with zstd streams.
 package zstd
 
 import (
@@ -23,6 +24,7 @@ import (
 	"github.com/klauspost/compress/zstd"
 )
 
+// MagicHeader is the start of zstd files.
 var MagicHeader = []byte{'\x28', '\xb5', '\x2f', '\xfd'}
 
 // ReadCloser reads uncompressed input data from the io.ReadCloser and

pkg/authn/k8schain/go.mod

@@ -1,6 +1,6 @@
 module github.com/google/go-containerregistry/pkg/authn/k8schain
 
-go 1.17
+go 1.18
 
 replace (
 	github.com/google/go-containerregistry => ../../../

pkg/authn/kubernetes/go.mod

@@ -1,6 +1,6 @@
 module github.com/google/go-containerregistry/pkg/authn/kubernetes
 
-go 1.17
+go 1.18
 
 replace github.com/google/go-containerregistry => ../../../
 

pkg/authn/kubernetes/keychain_test.go

@@ -365,7 +365,7 @@ func testResolve(t *testing.T, kc authn.Keychain, target authn.Resource, expecte
 	}
 }
 
-func toJSON(t *testing.T, obj interface{}) []byte {
+func toJSON(t *testing.T, obj any) []byte {
 	t.Helper()
 
 	bites, err := json.Marshal(obj)

pkg/crane/crane_test.go

@@ -532,7 +532,7 @@ func TestBadInputs(t *testing.T) {
 
 	// e drops the first parameter so we can use the result of a function
 	// that returns two values as an expression above. This is a bit of a go quirk.
-	e := func(_ interface{}, err error) error {
+	e := func(_ any, err error) error {
 		return err
 	}
 

pkg/name/errors.go

@@ -35,7 +35,7 @@ func (e *ErrBadName) Is(target error) bool {
 }
 
 // newErrBadName returns a ErrBadName which returns the given formatted string from Error().
-func newErrBadName(fmtStr string, args ...interface{}) *ErrBadName {
+func newErrBadName(fmtStr string, args ...any) *ErrBadName {
 	return &ErrBadName{fmt.Sprintf(fmtStr, args...)}
 }
 

pkg/v1/mutate/mutate.go

@@ -163,7 +163,7 @@ func (a arbitraryRawManifest) RawManifest() ([]byte, error) {
 	if err != nil {
 		return nil, err
 	}
-	var m map[string]interface{}
+	var m map[string]any
 	if err := json.Unmarshal(b, &m); err != nil {
 		return nil, err
 	}