Merge pull request #1447 from prometheus/fabxc/alertfix

Make copying alerting state safer.

rules/alerting.go

@@ -110,6 +110,10 @@ func (rule *AlertingRule) Name() string {
 	return rule.name
 }
 
+func (r *AlertingRule) equal(o *AlertingRule) bool {
+	return r.name == o.name && r.labels.Equal(o.labels)
+}
+
 func (r *AlertingRule) sample(alert *Alert, ts model.Time, set bool) *model.Sample {
 	metric := model.Metric(r.labels.Clone())
 

rules/manager.go

@@ -212,8 +212,12 @@ func (g *Group) copyState(from *Group) {
 			if !ok {
 				continue
 			}
-			if far.Name() == ar.Name() {
-				ar.active = far.active
+			// TODO(fabxc): forbid same alert definitions that are not unique by
+			// at least on static label or alertname?
+			if far.equal(ar) {
+				for fp, a := range far.active {
+					ar.active[fp] = a
+				}
 			}
 		}
 	}