From 7b4d7d7ad27d1321b4aa49c6d03e14e1365cbc63 Mon Sep 17 00:00:00 2001
From: Craig Perkins <cwperx@amazon.com>
Date: Fri, 13 Dec 2024 20:29:36 -0500
Subject: [PATCH] Ensure only single instance for each classpath extension

Signed-off-by: Craig Perkins <cwperx@amazon.com>
---
 .../java/org/opensearch/plugins/PluginsService.java  | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/server/src/main/java/org/opensearch/plugins/PluginsService.java b/server/src/main/java/org/opensearch/plugins/PluginsService.java
index a6298b8b4da6f..c3db32874d260 100644
--- a/server/src/main/java/org/opensearch/plugins/PluginsService.java
+++ b/server/src/main/java/org/opensearch/plugins/PluginsService.java
@@ -159,8 +159,8 @@ public PluginsService(
             pluginsLoaded.add(new Tuple<>(pluginInfo, plugin));
             pluginsList.add(pluginInfo);
             pluginsNames.add(pluginInfo.getName());
-            loadExtensions(pluginsLoaded);
         }
+        loadExtensions(pluginsLoaded);
 
         Set<Bundle> seenBundles = new LinkedHashSet<>();
         List<PluginInfo> modulesList = new ArrayList<>();
@@ -571,9 +571,17 @@ private static void loadExtensionsForPlugin(ExtensiblePlugin extensiblePlugin, L
         ExtensiblePlugin.ExtensionLoader extensionLoader = new ExtensiblePlugin.ExtensionLoader() {
             @Override
             public <T> List<T> loadExtensions(Class<T> extensionPointType) {
+                Set<Class<?>> seenClasses = new LinkedHashSet<>();
                 List<T> result = new ArrayList<>();
+
                 for (Plugin extendingPlugin : extendingPlugins) {
-                    result.addAll(createExtensions(extensionPointType, extendingPlugin));
+                    List<? extends T> extensions = createExtensions(extensionPointType, extendingPlugin);
+                    for (T extension : extensions) {
+                        // Only add if we haven't seen this class before, needed for classpath extensions for testing
+                        if (seenClasses.add(extension.getClass())) {
+                            result.add(extension);
+                        }
+                    }
                 }
                 return Collections.unmodifiableList(result);
             }