docker/docker_image_dest.go
func (c *dockerClient) deleteOneSignature(url *url.URL) (missing bool, err error) {
	switch url.Scheme {
	case "file":
		logrus.Debugf("Deleting %s", url.Path)
		err := os.Remove(url.Path)
		if err != nil && os.IsNotExist(err) {
			return true, nil
		}
		return false, err

	case "http", "https":
		return false, errors.Errorf("Writing directly to a %s sigstore %s is not supported. Configure a sigstore-staging: location", url.Scheme, url.String())
	default:
		return false, errors.Errorf("Unsupported scheme when deleting signature from %s", url.String())
	}
}
func (c *dockerClient) deleteOneSignature(url *url.URL) (missing bool, err error) {
	switch url.Scheme {
	case "file":
		logrus.Debugf("Deleting %s", url.Path)
		err := os.Remove(url.Path)
		if err != nil && os.IsNotExist(err) {
			return true, nil
		}
		return false, err

	case "http", "https":
		return false, errors.Errorf("Writing directly to a %s sigstore %s is not supported. Configure a sigstore-staging: location", url.Scheme, url.String())
	default:
		return false, errors.Errorf("Unsupported scheme when deleting signature from %s", url.String())
	}
}
// deleteOneSignature deletes a signature from url, if it exists.
// If it successfully determines that the signature does not exist, returns (true, nil)
// NOTE: Keep this in sync with docs/signature-protocols.md!