code: protected function getCredentialString()
      {
          if (!$this->hasAuth()) {
              return '';
          }
  
          return sprintf(
              ' %s--username %s --password %s ',
              $this->getAuthCache(),
              ProcessExecutor::escape($this->getUsername()),
              ProcessExecutor::escape($this->getPassword())
          );
      }
docs: Return the credential string for the svn command.
  
  Adds --no-auth-cache when credentials are present.
  
  @return string