internal/gofix and fix error wrapping (#76)

pkg/es/errors.go

@@ -17,29 +17,33 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
 package es
 
 import (
+	"errors"
 	"fmt"
+	"strings"
 
 	"github.com/elastic/go-elasticsearch/v9/typedapi/types"
 )
 
-func esErrorString(err error) string {
+func esErrorString(err error) error {
 	msg := err.Error()
 
 	switch e := err.(type) {
 	case *types.ElasticsearchError:
-		causes := ""
+		var causes strings.Builder
 
 		for _, cause := range e.ErrorCause.RootCause {
-			causes += fmt.Sprintf("%s\n", *cause.Reason)
+			// FIXME: re-activate linter here, see https://github.com/golangci/golangci-lint/issues/6662
+			//nolint:staticcheck
+			causes.WriteString(fmt.Sprintf("%s\n", *cause.Reason))
 		}
 
 		if e.ErrorCause.Reason != nil {
-			msg = *e.ErrorCause.Reason + ": " + causes
+			msg = *e.ErrorCause.Reason + ": " + causes.String()
 		} else {
 			msg = fmt.Sprintf("http status %d: ", e.Status)
 		}
 
 	}
 
-	return msg
+	return errors.New(msg)
 }