Remove superfluous nil check in Group.metrics

Signed-off-by: Marco Pracucci <marco@pracucci.com>

rules/group.go

@@ -592,9 +592,8 @@ func (g *Group) Eval(ctx context.Context, ts time.Time) {
 	}
 
 	wg.Wait()
-	if g.metrics != nil {
-		g.metrics.GroupSamples.WithLabelValues(GroupKey(g.File(), g.Name())).Set(samplesTotal.Load())
-	}
+
+	g.metrics.GroupSamples.WithLabelValues(GroupKey(g.File(), g.Name())).Set(samplesTotal.Load())
 	g.cleanupStaleSeries(ctx, ts)
 }
 

rules/manager_test.go

@@ -679,6 +679,7 @@ func TestDeletedRuleMarkedStale(t *testing.T) {
 			Appendable:                st,
 			RuleConcurrencyController: sequentialRuleEvalController{},
 		},
+		metrics: NewGroupMetrics(nil),
 	}
 	newGroup.CopyState(oldGroup)