Convert to using set

cmd/release-controller/prune_graph.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	releasecontroller "github.com/openshift/release-controller/pkg/release-controller"
 	"k8s.io/apimachinery/pkg/labels"
+	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/apimachinery/pkg/util/wait"
 	kv1core "k8s.io/client-go/kubernetes/typed/core/v1"
 	"k8s.io/klog"
@@ -49,29 +50,10 @@ func (c *Controller) PruneGraph(secretClient kv1core.SecretInterface, ns, name s
 		}
 	}
 
-	// To tags that are not in the From tags
-	pruneTagList := make([]string, 0, len(c.graph.To))
-	for _, tag := range toMissingList {
-		if !releasecontroller.StringSliceContains(fromMissingList, tag) {
-			pruneTagList = append(pruneTagList, tag)
-		}
-	}
-
-	// From tags that are not in the To tags
-	for _, tag := range fromMissingList {
-		if !releasecontroller.StringSliceContains(toMissingList, tag) {
-			pruneTagList = append(pruneTagList, tag)
-		}
-	}
-
-	// Tags that are in both the From and To lists
-	for _, tag := range toMissingList {
-		if releasecontroller.StringSliceContains(fromMissingList, tag) {
-			pruneTagList = append(pruneTagList, tag)
-		}
-	}
-
+	// Combine the 2 lists into a set to eliminate duplicates
+	pruneTagList := sets.NewString(append(toMissingList, fromMissingList...)...).UnsortedList()
 	klog.V(2).Infof("Pruning %d/%d tags from release controller graph\n", len(pruneTagList), len(c.graph.To))
+
 	c.graph.PruneTags(pruneTagList)
 
 	if confirm {