From c11687e8b3a487045f64837a74c5673cda6fd5db Mon Sep 17 00:00:00 2001
From: daguimu <daguimu.geek@gmail.com>
Date: Wed, 25 Mar 2026 19:42:22 +0800
Subject: [PATCH] fix: use thread-safe collections in SchemaDescriptorRegistry

SchemaDescriptorRegistry has three thread-safety issues:

1. SERVICES uses a plain HashSet accessed concurrently during service
   registration. Concurrent HashSet.add() can corrupt internal state.

2. addExtension() has a check-then-act race on EXTENSIONS: two threads
   can both see containsKey()==false, both put a new HashMap, and one
   overwrites the other's entries.

3. The inner HashMap in EXTENSIONS is also accessed concurrently via
   fdMap.put() without synchronization.

Fix: Replace HashSet with ConcurrentHashMap.newKeySet(), replace
check-then-act with computeIfAbsent(), and use ConcurrentHashMap
for the inner map.
---
 .../protocol/tri/service/SchemaDescriptorRegistry.java | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/dubbo-rpc/dubbo-rpc-triple/src/main/java/org/apache/dubbo/rpc/protocol/tri/service/SchemaDescriptorRegistry.java b/dubbo-rpc/dubbo-rpc-triple/src/main/java/org/apache/dubbo/rpc/protocol/tri/service/SchemaDescriptorRegistry.java
index 0eb6fc68256..9a898d2f81b 100644
--- a/dubbo-rpc/dubbo-rpc-triple/src/main/java/org/apache/dubbo/rpc/protocol/tri/service/SchemaDescriptorRegistry.java
+++ b/dubbo-rpc/dubbo-rpc-triple/src/main/java/org/apache/dubbo/rpc/protocol/tri/service/SchemaDescriptorRegistry.java
@@ -18,8 +18,6 @@
 
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -35,7 +33,7 @@ public class SchemaDescriptorRegistry {
 
     private static final Map<String, Map<Integer, FileDescriptor>> EXTENSIONS = new ConcurrentHashMap<>();
 
-    private static final Set<String> SERVICES = new HashSet<>();
+    private static final Set<String> SERVICES = ConcurrentHashMap.newKeySet();
 
     public static void addSchemaDescriptor(String serviceName, FileDescriptor fd) {
         SERVICES.add(serviceName);
@@ -58,11 +56,7 @@ private static void addType(Descriptor descriptor) {
     private static void addExtension(FieldDescriptor extension, FileDescriptor fd) {
         String name = extension.getContainingType().getFullName();
         int number = extension.getNumber();
-        if (!EXTENSIONS.containsKey(name)) {
-            EXTENSIONS.put(name, new HashMap<>());
-        }
-        Map<Integer, FileDescriptor> fdMap = EXTENSIONS.get(name);
-        fdMap.put(number, fd);
+        EXTENSIONS.computeIfAbsent(name, k -> new ConcurrentHashMap<>()).put(number, fd);
     }
 
     public static FileDescriptor getFileDescriptorByExtensionAndNumber(String extension, int number) {