Limits need to call tag API when explicit version specified

Signed-off-by: Andrew Block <andy.block@gmail.com>

pkg/downloader/chart_downloader.go

@@ -23,6 +23,7 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/Masterminds/semver/v3"
 	"github.com/pkg/errors"
 
 	"helm.sh/helm/v3/internal/fileutil"
@@ -141,22 +142,31 @@ func (c *ChartDownloader) DownloadTo(ref, version, dest string) (string, *proven
 }
 
 func (c *ChartDownloader) getOciURI(ref, version string, u *url.URL) (*url.URL, error) {
-	// Retrieve list of repository tags
-	tags, err := c.RegistryClient.Tags(strings.TrimPrefix(ref, fmt.Sprintf("%s://", registry.OCIScheme)))
-	if err != nil {
-		return nil, err
-	}
-	if len(tags) == 0 {
-		return nil, errors.Errorf("Unable to locate any tags in provided repository: %s", ref)
-	}
+	var tag string
+	var err error
+
+	// Evaluate whether an explicit version has been provided. Otherwise, determine version to use
+	_, errSemVer := semver.NewVersion(version)
+	if errSemVer == nil {
+		tag = version
+	} else {
+		// Retrieve list of repository tags
+		tags, err := c.RegistryClient.Tags(strings.TrimPrefix(ref, fmt.Sprintf("%s://", registry.OCIScheme)))
+		if err != nil {
+			return nil, err
+		}
+		if len(tags) == 0 {
+			return nil, errors.Errorf("Unable to locate any tags in provided repository: %s", ref)
+		}
 
-	// Determine if version provided
-	// If empty, try to get the highest available tag
-	// If exact version, try to find it
-	// If semver constraint string, try to find a match
-	tag, err := registry.GetTagMatchingVersionOrConstraint(tags, version)
-	if err != nil {
-		return nil, err
+		// Determine if version provided
+		// If empty, try to get the highest available tag
+		// If exact version, try to find it
+		// If semver constraint string, try to find a match
+		tag, err = registry.GetTagMatchingVersionOrConstraint(tags, version)
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	u.Path = fmt.Sprintf("%s:%s", u.Path, tag)