validate openapi exclusivity

cmd/print.go

@@ -19,6 +19,7 @@ package cmd
 import (
 	"fmt"
 	"os"
+	"slices"
 	"strings"
 
 	"github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw"
@@ -237,6 +238,13 @@ func newPrintCommand() *cobra.Command {
 		Use:   "print",
 		Short: "Prints Gateway API objects generated from ingress and provider-specific resources.",
 		RunE:  pr.PrintGatewayAPIObjects,
+		PreRunE: func(cmd *cobra.Command, args []string) error {
+			openAPIExist := slices.Contains(pr.providers, "openapi3")
+			if openAPIExist && len(pr.providers) != 1 {
+				return fmt.Errorf("openapi3 must be the only provider when specified")
+			}
+			return nil
+		},
 	}
 
 	cmd.Flags().StringVarP(&pr.outputFormat, "output", "o", "yaml",