From 504ae9ce277614e88d9868c9bf7834c5a7484d7f Mon Sep 17 00:00:00 2001
From: Simon Brennecke <simon@brennecke-it.net>
Date: Wed, 1 Apr 2026 13:53:55 +0200
Subject: [PATCH] fix JENKINS-74824 / issue #1938

---
 src/main/java/hudson/plugins/ec2/EC2Cloud.java | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/main/java/hudson/plugins/ec2/EC2Cloud.java b/src/main/java/hudson/plugins/ec2/EC2Cloud.java
index a329cb6a4..4dcdc4974 100644
--- a/src/main/java/hudson/plugins/ec2/EC2Cloud.java
+++ b/src/main/java/hudson/plugins/ec2/EC2Cloud.java
@@ -415,6 +415,11 @@ public void addTemplate(SlaveTemplate newTemplate) throws Exception {
             throw new Exception(
                     String.format("A SlaveTemplate with description %s already exists", newTemplateDescription));
         }
+        if (newTemplate.parent != null) {
+            throw new Exception(
+                    String.format("The new SlaveTemplate with description %s already has a parent", newTemplateDescription));
+        }
+        newTemplate.parent = this;
         List<SlaveTemplate> templatesHolder = new ArrayList<>(templates);
         templatesHolder.add(newTemplate);
         templates = templatesHolder;