Fix NCS clusters with labels (#100)

* Fix NCS clusters with labels

Don't try to read/subtract the project labels

* fix corner case when emptying cluster labels

previously, if a cluster update removed all cluster labels, subsequent
runs with no change would show a permanent difference to be applied

metakube/resource_cluster.go

@@ -324,18 +324,12 @@ func metakubeResourceClusterRead(ctx context.Context, d *schema.ResourceData, m
 	_ = d.Set("dc_name", r.Payload.Spec.Cloud.DatacenterName)
 	_ = d.Set("name", r.Payload.Name)
 	if len(r.Payload.Labels) > 0 {
-		resourceProject, err := getProject(k, projectID)
-		if err != nil {
-			return diag.FromErr(err)
-		}
-		if labels := mapExclude(r.Payload.Labels, resourceProject.Labels); len(labels) > 0 {
-			if err := d.Set("labels", labels); err != nil {
-				return diag.Diagnostics{{
-					Severity:      diag.Error,
-					Summary:       "Invalid value",
-					AttributePath: cty.Path{cty.GetAttrStep{Name: "labels"}},
-				}}
-			}
+		if err := d.Set("labels", r.Payload.Labels); err != nil {
+			return diag.Diagnostics{{
+				Severity:      diag.Error,
+				Summary:       "Invalid value",
+				AttributePath: cty.Path{cty.GetAttrStep{Name: "labels"}},
+			}}
 		}
 	}
 
@@ -638,20 +632,29 @@ func metakubeResourceClusterSendPatchReq(ctx context.Context, d *schema.Resource
 		"spec":   clusterSpec,
 	})
 
+	var patchedCluster *models.Cluster
 	err := retry.RetryContext(ctx, d.Timeout(schema.TimeoutUpdate), func() *retry.RetryError {
-		_, err := k.client.Project.PatchClusterV2(p, k.auth)
+		patchResult, err := k.client.Project.PatchClusterV2(p, k.auth)
 		if err != nil {
 			if e, ok := err.(*project.PatchClusterV2Default); ok && e.Code() == http.StatusConflict {
 				return retry.RetryableError(fmt.Errorf("cluster patch conflict: %v", err))
 			}
 			return retry.NonRetryableError(fmt.Errorf("patch cluster '%s': %v", d.Id(), stringifyResponseError(err)))
 		}
+		patchedCluster = patchResult.GetPayload()
 		return nil
 	})
 	if err != nil {
 		return err
 	}
 
+	if patchedCluster.Labels == nil {
+		// if the cluster has no labels after patching, set them to nil in the state data explicitly
+		// otherwise, if the cluster had labels before that were all removed by the patch, remnants
+		// (empty labels) would remain in the data, showing up as a permanent difference on subsequent runs
+		_ = d.Set("labels", nil)
+	}
+
 	return nil
 }