sg: ops - only replace registry if there is an existing reg (#57526)

only replace registry if there is an existing reg

Author: burmudar

dev/sg/internal/images/helm.go

@@ -55,11 +55,14 @@ func UpdateHelmManifest(ctx context.Context, registry Registry, path string, op
 			std.Out.WriteLine(output.Styled(output.StyleWarning, fmt.Sprintf("skipping updating registry as it's public which we assume is the default, %q", err.Error())))
 		}
 	}
-	valuesFileString = strings.ReplaceAll(
-		valuesFileString,
-		existingReg,
-		filepath.Join(registry.Host(), registry.Org()),
-	)
+
+	if existingReg != "" {
+		valuesFileString = strings.ReplaceAll(
+			valuesFileString,
+			existingReg,
+			filepath.Join(registry.Host(), registry.Org()),
+		)
+	}
 
 	// Collect all images.
 	var imgs []string

dev/sg/sg_ops.go

@@ -155,7 +155,7 @@ func opsUpdateImages(
 	path string,
 	registryType string,
 	deploymentType string,
-	pintag string,
+	pinTag string,
 	dockerUsername string,
 	dockerPassword string,
 	skipImages []string,
@@ -190,15 +190,15 @@ func opsUpdateImages(
 			return false
 		}
 
-		if pintag != "" {
-			std.Out.WriteNoticef("pinning images to tag %q", pintag)
+		if pinTag != "" {
+			std.Out.WriteNoticef("pinning images to tag %q", pinTag)
 			// We're pinning a tag.
 			op = func(registry images.Registry, r *images.Repository) (*images.Repository, error) {
 				if !images.IsSourcegraph(r) || shouldSkip(r) {
 					return nil, images.ErrNoUpdateNeeded
 				}
 
-				newR, err := registry.GetByTag(r.Name(), pintag)
+				newR, err := registry.GetByTag(r.Name(), pinTag)
 				if err != nil {
 					return nil, err
 				}