Restore incident rules gracefully

internal/incident/incident.go

@@ -635,17 +635,6 @@ func (i *Incident) processAcknowledgementEvent(ctx context.Context, tx *sqlx.Tx,
 	return nil
 }
 
-// RestoreEscalationStateRules restores this incident's rules based on the given escalation states.
-func (i *Incident) RestoreEscalationStateRules() {
-	i.runtimeConfig.RLock()
-	defer i.runtimeConfig.RUnlock()
-
-	for _, state := range i.EscalationState {
-		escalation := i.runtimeConfig.GetRuleEscalation(state.RuleEscalationID)
-		i.Rules[escalation.RuleID] = struct{}{}
-	}
-}
-
 // getRecipientsChannel returns all the configured channels of the current incident and escalation recipients.
 func (i *Incident) getRecipientsChannel(t time.Time) contactChannels {
 	contactChs := make(contactChannels)

internal/incident/incidents.go

@@ -171,6 +171,15 @@ func LoadOpenIncidents(ctx context.Context, db *icingadb.DB, logger *logging.Log
 						for _, i := range incidentsByObjId {
 							if i.ID() == state.IncidentID {
 								i.EscalationState[state.RuleEscalationID] = state
+
+								// Restore the incident rule matching the current escalation state if any.
+								i.runtimeConfig.RLock()
+								escalation := i.runtimeConfig.GetRuleEscalation(state.RuleEscalationID)
+								if escalation != nil {
+									i.Rules[escalation.RuleID] = struct{}{}
+								}
+								i.runtimeConfig.RUnlock()
+
 								break
 							}
 						}
@@ -205,7 +214,6 @@ func LoadOpenIncidents(ctx context.Context, db *icingadb.DB, logger *logging.Log
 					for _, i := range incidentsByObjId {
 						i.logger = logger.With(zap.String("object", i.Object.DisplayName()), zap.String("incident", i.String()))
 
-						i.RestoreEscalationStateRules()
 						i.RetriggerEscalations(&event.Event{
 							Time:    time.Now(),
 							Type:    event.TypeInternal,