From 541b8bd802df3e90a2acdf6898871f9ee85afe34 Mon Sep 17 00:00:00 2001
From: Craig Perkins <cwperx@amazon.com>
Date: Mon, 15 Jul 2024 14:31:38 -0400
Subject: [PATCH] Use single data structure to keep track of system indices

Signed-off-by: Craig Perkins <cwperx@amazon.com>
---
 .../org/opensearch/indices/SystemIndexRegistry.java    |  2 --
 .../java/org/opensearch/indices/SystemIndices.java     | 10 ++++++++--
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/server/src/main/java/org/opensearch/indices/SystemIndexRegistry.java b/server/src/main/java/org/opensearch/indices/SystemIndexRegistry.java
index ba57532502d82..9f24a687ba51a 100644
--- a/server/src/main/java/org/opensearch/indices/SystemIndexRegistry.java
+++ b/server/src/main/java/org/opensearch/indices/SystemIndexRegistry.java
@@ -45,7 +45,6 @@ public class SystemIndexRegistry {
     );
 
     private volatile static String[] SYSTEM_INDEX_PATTERNS = new String[0];
-    volatile static Collection<SystemIndexDescriptor> SYSTEM_INDEX_DESCRIPTORS = Collections.emptyList();
     volatile static Map<String, Collection<SystemIndexDescriptor>> SYSTEM_INDEX_DESCRIPTORS_MAP = Collections.emptyMap();
 
     static void register(Map<String, Collection<SystemIndexDescriptor>> pluginAndModulesDescriptors) {
@@ -58,7 +57,6 @@ static void register(Map<String, Collection<SystemIndexDescriptor>> pluginAndMod
         descriptors.add(TASK_INDEX_DESCRIPTOR);
 
         SYSTEM_INDEX_DESCRIPTORS_MAP = descriptorsMap;
-        SYSTEM_INDEX_DESCRIPTORS = descriptors.stream().collect(Collectors.toUnmodifiableList());
         SYSTEM_INDEX_PATTERNS = descriptors.stream().map(SystemIndexDescriptor::getIndexPattern).toArray(String[]::new);
     }
 
diff --git a/server/src/main/java/org/opensearch/indices/SystemIndices.java b/server/src/main/java/org/opensearch/indices/SystemIndices.java
index bbf58fe91512f..a0b2cab060214 100644
--- a/server/src/main/java/org/opensearch/indices/SystemIndices.java
+++ b/server/src/main/java/org/opensearch/indices/SystemIndices.java
@@ -63,7 +63,9 @@ public class SystemIndices {
 
     public SystemIndices(Map<String, Collection<SystemIndexDescriptor>> pluginAndModulesDescriptors) {
         SystemIndexRegistry.register(pluginAndModulesDescriptors);
-        this.runAutomaton = buildCharacterRunAutomaton(SystemIndexRegistry.SYSTEM_INDEX_DESCRIPTORS);
+        this.runAutomaton = buildCharacterRunAutomaton(
+            SystemIndexRegistry.SYSTEM_INDEX_DESCRIPTORS_MAP.values().stream().flatMap(Collection::stream).collect(Collectors.toList())
+        );
     }
 
     /**
@@ -91,7 +93,11 @@ public boolean isSystemIndex(String indexName) {
      * @throws IllegalStateException if multiple descriptors match the name
      */
     public @Nullable SystemIndexDescriptor findMatchingDescriptor(String name) {
-        final List<SystemIndexDescriptor> matchingDescriptors = SystemIndexRegistry.SYSTEM_INDEX_DESCRIPTORS.stream()
+        List<SystemIndexDescriptor> allDescriptors = SystemIndexRegistry.SYSTEM_INDEX_DESCRIPTORS_MAP.values()
+            .stream()
+            .flatMap(Collection::stream)
+            .collect(Collectors.toList());
+        final List<SystemIndexDescriptor> matchingDescriptors = allDescriptors.stream()
             .filter(descriptor -> descriptor.matchesIndexPattern(name))
             .collect(Collectors.toList());