fix: snapshot commands panic if snapshot don't exists (backport cosmo…

…s#16138) (cosmos#16139)

Co-authored-by: yihuang <huang@crypto.com>
Co-authored-by: marbar3778 <marbar3778@yahoo.com>
Co-authored-by: Julien Robert <julien@rbrt.fr>

client/snapshot/dump.go

@@ -3,6 +3,7 @@ package snapshot
 import (
 	"archive/tar"
 	"compress/gzip"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -48,6 +49,10 @@ func DumpArchiveCmd() *cobra.Command {
 				return err
 			}
 
+			if snapshot == nil {
+				return errors.New("snapshot doesn't exist")
+			}
+
 			bz, err := snapshot.Marshal()
 			if err != nil {
 				return err

snapshots/manager.go

@@ -424,6 +424,10 @@ func (m *Manager) RestoreLocalSnapshot(height uint64, format uint32) error {
 		return err
 	}
 
+	if snapshot == nil {
+		return fmt.Errorf("snapshot doesn't exist, height: %d, format: %d", height, format)
+	}
+
 	m.mtx.Lock()
 	defer m.mtx.Unlock()