fix: close temp file handle before removal (#3672)

* fix(dind): close temp file handle before removal

On some OS (such as Windows), keeping a file descriptor open prevents you from deleting the file.

* fix(k3s): close temp file handle before removal

On some OS (such as Windows), keeping a file descriptor open prevents you from deleting the file.

Author: acouvreur

modules/dind/dind.go

@@ -81,6 +81,11 @@ func (c *Container) LoadImage(ctx context.Context, image string) (err error) {
 	if err != nil {
 		return fmt.Errorf("create temporary images file: %w", err)
 	}
+	// Close the file handle immediately: SaveImages and CopyFileToContainer
+	// open the file by name.
+	if err = imagesTar.Close(); err != nil {
+		return fmt.Errorf("close temporary images file: %w", err)
+	}
 	defer func() {
 		err = errors.Join(err, os.Remove(imagesTar.Name()))
 	}()

modules/k3s/k3s.go

@@ -193,6 +193,11 @@ func (c *K3sContainer) LoadImagesWithOpts(ctx context.Context, images []string,
 	if err != nil {
 		return fmt.Errorf("creating temporary images file %w", err)
 	}
+	// Close the file handle immediately: SaveImages and CopyFileToContainer
+	// open the file by name.
+	if err = imagesTar.Close(); err != nil {
+		return fmt.Errorf("close temporary images file: %w", err)
+	}
 	defer func() {
 		_ = os.Remove(imagesTar.Name())
 	}()