Enable more linters for new code

kyaml/filesys/fsondisk.go

@@ -9,6 +9,8 @@ import (
 	"log"
 	"os"
 	"path/filepath"
+
+	"sigs.k8s.io/kustomize/kyaml/errors"
 )
 
 var _ FileSystem = fsOnDisk{}
@@ -128,7 +130,7 @@ func (fsOnDisk) ReadFile(name string) ([]byte, error) { return ioutil.ReadFile(n
 
 // WriteFile delegates to ioutil.WriteFile with read/write permissions.
 func (fsOnDisk) WriteFile(name string, c []byte) error {
-	return ioutil.WriteFile(name, c, 0666) //nolint:gosec
+	return errors.Wrap(ioutil.WriteFile(name, c, 0666)) //nolint:gosec
 }
 
 // Walk delegates to filepath.Walk.

kyaml/openapi/openapi.go

@@ -317,7 +317,7 @@ func toTypeMeta(ext interface{}) (yaml.TypeMeta, bool) {
 	}
 
 	apiVersion := m[versionKey].(string)
-	if g := m[groupKey].(string); g != "" {
+	if g, ok := m[groupKey].(string); ok && g != "" {
 		apiVersion = g + "/" + apiVersion
 	}
 	return yaml.TypeMeta{Kind: m[kindKey].(string), APIVersion: apiVersion}, true