From c150352ecd22d3fe8149e8b59330000545a822fe Mon Sep 17 00:00:00 2001
From: Andrii Shvaika <ashvayka@thingsboard.io>
Date: Wed, 8 Dec 2021 18:38:46 +0200
Subject: [PATCH] Save RuleChain MetaData method fix

---
 .../server/service/rule/DefaultTbRuleChainService.java         | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/application/src/main/java/org/thingsboard/server/service/rule/DefaultTbRuleChainService.java b/application/src/main/java/org/thingsboard/server/service/rule/DefaultTbRuleChainService.java
index 14f56d1f6b..e9795ce15f 100644
--- a/application/src/main/java/org/thingsboard/server/service/rule/DefaultTbRuleChainService.java
+++ b/application/src/main/java/org/thingsboard/server/service/rule/DefaultTbRuleChainService.java
@@ -36,6 +36,7 @@ import org.thingsboard.server.dao.relation.RelationService;
 import org.thingsboard.server.dao.rule.RuleChainService;
 import org.thingsboard.server.queue.util.TbCoreComponent;
 
+import java.util.Collections;
 import java.util.Comparator;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -111,7 +112,7 @@ public class DefaultTbRuleChainService implements TbRuleChainService {
         Set<RuleChainId> ruleChainIds = new HashSet<>();
         log.debug("[{}][{}] Going to update links in related rule chains", tenantId, ruleChainId);
         if (result.getUpdatedRuleNodes() == null || result.getUpdatedRuleNodes().isEmpty()) {
-            return null;
+            return Collections.emptyList();
         }
 
         Set<String> oldLabels = new HashSet<>();