fix condition check for extraOpts validation

Author: nezorflame

cmd/minikube/cmd/start.go

@@ -873,7 +873,7 @@ func validateFlags(cmd *cobra.Command, drvName string) {
 	}
 
 	// validate kubeadm extra args
-	if invalidOpts := bsutil.FindInvalidExtraConfigFlags(config.ExtraOptions); invalidOpts != nil {
+	if invalidOpts := bsutil.FindInvalidExtraConfigFlags(config.ExtraOptions); len(invalidOpts) > 0 {
 		out.ErrT(
 			out.Warning,
 			"These --extra-config parameters are invalid: {{.invalid_extra_opts}}",

pkg/minikube/bootstrapper/bsutil/extraconfig.go

@@ -148,7 +148,7 @@ func defaultOptionsForComponentAndVersion(component string, version semver.Versi
 
 // newComponentOptions creates a new componentOptions
 func newComponentOptions(opts config.ExtraOptionSlice, version semver.Version, featureGates string, cp config.Node) ([]componentOptions, error) {
-	if invalidOpts := FindInvalidExtraConfigFlags(opts); invalidOpts != nil {
+	if invalidOpts := FindInvalidExtraConfigFlags(opts); len(invalidOpts) > 0 {
 		return nil, fmt.Errorf("unknown components %v. valid components are: %v", invalidOpts, KubeadmExtraConfigOpts)
 	}