code: func (s *BuiltInAuthenticationOptions) Validate() []error {
  	allErrors := []error{}
  
  	if s.OIDC != nil && (len(s.OIDC.IssuerURL) > 0) != (len(s.OIDC.ClientID) > 0) {
  		allErrors = append(allErrors, fmt.Errorf("oidc-issuer-url and oidc-client-id should be specified together"))
  	}
  
  	if s.ServiceAccounts != nil && len(s.ServiceAccounts.Issuer) > 0 && strings.Contains(s.ServiceAccounts.Issuer, ":") {
  		if _, err := url.Parse(s.ServiceAccounts.Issuer); err != nil {
  			allErrors = append(allErrors, fmt.Errorf("service-account-issuer contained a ':' but was not a valid URL: %v", err))
  		}
  	}
  	if s.ServiceAccounts != nil && utilfeature.DefaultFeatureGate.Enabled(features.BoundServiceAccountTokenVolume) {
  		if !utilfeature.DefaultFeatureGate.Enabled(features.TokenRequest) || !utilfeature.DefaultFeatureGate.Enabled(features.TokenRequestProjection) {
  			allErrors = append(allErrors, errors.New("If the BoundServiceAccountTokenVolume feature is enabled,"+
  				" the TokenRequest and TokenRequestProjection features must also be enabled"))
  		}
  		if len(s.ServiceAccounts.Issuer) == 0 {
  			allErrors = append(allErrors, errors.New("service-account-issuer is a required flag when BoundServiceAccountTokenVolume is enabled"))
  		}
  		if len(s.ServiceAccounts.KeyFiles) == 0 {
  			allErrors = append(allErrors, errors.New("service-account-key-file is a required flag when BoundServiceAccountTokenVolume is enabled"))
  		}
  	}
  
  	return allErrors
  }
docs: // Validate checks invalid config combination