fix: prevent panic when ChartDownloader is called

Return an error instead of panicing if OCI registry client is not provided

Signed-off-by: Evans Mungai <mbuevans@gmail.com>

pkg/downloader/chart_downloader.go

@@ -164,6 +164,10 @@ func (c *ChartDownloader) ResolveChartVersion(ref, version string) (*url.URL, er
 	}
 
 	if registry.IsOCI(u.String()) {
+		if c.RegistryClient == nil {
+			return nil, fmt.Errorf("unable to resolve chart version for %s, missing registry client", ref)
+		}
+
 		return c.RegistryClient.ValidateReference(ref, version, u)
 	}
 

pkg/downloader/chart_downloader_test.go

@@ -20,6 +20,8 @@ import (
 	"path/filepath"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
+
 	"helm.sh/helm/v4/internal/test/ensure"
 	"helm.sh/helm/v4/pkg/cli"
 	"helm.sh/helm/v4/pkg/getter"
@@ -324,6 +326,22 @@ func TestDownloadTo_VerifyLater(t *testing.T) {
 	}
 }
 
+func TestDownloadTo_MissingRegistryClient(t *testing.T) {
+	c := ChartDownloader{
+		Getters: getter.Providers{
+			getter.Provider{
+				Schemes: []string{"oci"},
+				New:     getter.NewOCIGetter,
+			},
+		},
+	}
+
+	ref := "oci://someurl"
+	version := "latest"
+	_, _, err := c.DownloadTo(ref, version, t.TempDir())
+	assert.Error(t, err)
+}
+
 func TestScanReposForURL(t *testing.T) {
 	c := ChartDownloader{
 		Out:              os.Stderr,