Fix ApiVersion overwrite during conversion

During conversion webhook handler controller-runtime sets desire meta api version of the
destination resource from the Kubernetes API server request. Round trip marshall and unmarshall
is overwriting metadata.

Reference

https://github.com/kubernetes-sigs/controller-runtime/blob/f4ca78ebc00a4717ecd1c2daea1874d69ddd0137/pkg/webhook/conversion/conversion.go#L101

src/go/k8s/api/redpanda/v1alpha1/redpanda_conversion.go

@@ -12,6 +12,7 @@ package v1alpha1
 import (
 	"encoding/json"
 	"fmt"
+	"k8s.io/apimachinery/pkg/api/meta"
 
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/conversion"
@@ -32,6 +33,15 @@ func (r *Redpanda) SetupWebhookWithManager(mgr ctrl.Manager) error {
 func (src *Redpanda) ConvertTo(dstRaw conversion.Hub) error { // nolint:stylecheck // `src` as a received helps with readability
 	dst := dstRaw.(*v1alpha2.Redpanda)
 
+	// controller-runtime respects desired api version and kind from the
+	// Kubernetes API server and set it in destination resource
+	// https://github.com/kubernetes-sigs/controller-runtime/blob/f4ca78ebc00a4717ecd1c2daea1874d69ddd0137/pkg/webhook/conversion/conversion.go#L101
+	//
+	// By using round trip json marshall/unmarshall the TypeMeta is being
+	// overwritten. The desiredAPIVersion is saved for later rollback.
+	t, err := meta.TypeAccessor(dst)
+	desiredAPIVersion := t.GetAPIVersion()
+
 	b, err := json.Marshal(src)
 	if err != nil {
 		return fmt.Errorf("marshaling %T: %w", Redpanda{}, err)
@@ -41,13 +51,24 @@ func (src *Redpanda) ConvertTo(dstRaw conversion.Hub) error { // nolint:styleche
 		return fmt.Errorf("unmarshaling %T: %w", v1alpha2.Redpanda{}, err)
 	}
 
+	t.SetAPIVersion(desiredAPIVersion)
+
 	return nil
 }
 
 // ConvertFrom converts from the Hub version (v1) to this version.
 func (dst *Redpanda) ConvertFrom(srcRaw conversion.Hub) error { // nolint:stylecheck // `dst` as a received helps with readability
 	src := srcRaw.(*v1alpha2.Redpanda)
 
+	// controller-runtime respects desired api version and kind from the
+	// Kubernetes API server and set it in destination resource
+	// https://github.com/kubernetes-sigs/controller-runtime/blob/f4ca78ebc00a4717ecd1c2daea1874d69ddd0137/pkg/webhook/conversion/conversion.go#L101
+	//
+	// By using round trip json marshall/unmarshall the TypeMeta is being
+	// overwritten. The desiredAPIVersion is saved for later rollback.
+	t, err := meta.TypeAccessor(dst)
+	desiredAPIVersion := t.GetAPIVersion()
+
 	b, err := json.Marshal(src)
 	if err != nil {
 		return fmt.Errorf("marshaling %T: %w", v1alpha2.Redpanda{}, err)
@@ -56,5 +77,8 @@ func (dst *Redpanda) ConvertFrom(srcRaw conversion.Hub) error { // nolint:stylec
 	if err = json.Unmarshal(b, dst); err != nil {
 		return fmt.Errorf("unmarshaling %T: %w", Redpanda{}, err)
 	}
+
+	t.SetAPIVersion(desiredAPIVersion)
+
 	return nil
 }

src/go/k8s/api/redpanda/v1alpha1/redpanda_conversion_test.go

@@ -3,6 +3,7 @@ package v1alpha1_test
 import (
 	"encoding/json"
 	"fmt"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"regexp"
 	"strings"
 	"testing"
@@ -219,5 +220,12 @@ func CRDFuzzer() *fuzz.Fuzzer {
 		func(q *resource.Quantity, c fuzz.Continue) { // nolint:ineffassign,staticcheck // Fuzzing is weird, we're assigning to a pointer to pass the value out.
 			q = resource.NewQuantity(c.Int63(), resource.DecimalSI)
 		},
+		// TypeMeta is special case where ApiVersion needs to be empty. In the real webhook handler the apiVersion will be set
+		// by controller runtime.
+		func(typeMeta *metav1.TypeMeta, c fuzz.Continue) {
+			typeMeta = &metav1.TypeMeta{
+				Kind: c.RandString(),
+			}
+		},
 	).SkipFieldsWithPattern(regexp.MustCompile("Console|Config|Connectors|FieldsV1"))
 }