fix(android): crash concurrent access _registryByName (#117)

* fix(android): crash happening because _registryByName isn't properly lock guarded

* fix this pointer pointing to destructed class in thread

Author: hannojg

packages/react-native/ReactCommon/react/renderer/componentregistry/ComponentDescriptorRegistry.cpp

@@ -39,13 +39,16 @@ void ComponentDescriptorRegistry::addMultipleAsync(
   auto parametersCopy = parameters_;
   auto contextContainerCopy = contextContainer_;
 
-  // Start thread immediately
-  std::thread([this, providers = std::move(providers), parametersCopy, contextContainerCopy]() {
+  auto self = shared_from_this();
+
+  // Start detached thread - registry stays alive until completion due to strong self reference
+  std::thread([self, providers = std::move(providers), parametersCopy, contextContainerCopy]() {
     // Ensure this C++ thread is attached to the JVM before touching JNI
     #ifdef __ANDROID__
       facebook::jni::Environment::ensureCurrentThreadIsAttached();
     #endif
-      std::unique_lock lock(mutex_);
+
+    std::unique_lock lock(self->mutex_);
 
     for (const auto& provider : providers) {
       auto componentDescriptor = provider.constructor(
@@ -59,8 +62,8 @@ void ComponentDescriptorRegistry::addMultipleAsync(
       auto sharedComponentDescriptor =
           std::shared_ptr<const ComponentDescriptor>(std::move(componentDescriptor));
 
-      _registryByHandle[provider.handle] = sharedComponentDescriptor;
-      _registryByName[provider.name] = sharedComponentDescriptor;
+      self->_registryByHandle[provider.handle] = sharedComponentDescriptor;
+      self->_registryByName[provider.name] = sharedComponentDescriptor;
     }
   }).detach();
 }
@@ -89,6 +92,8 @@ void ComponentDescriptorRegistry::add(
 
 void ComponentDescriptorRegistry::registerComponentDescriptor(
     const SharedComponentDescriptor& componentDescriptor) const {
+  std::unique_lock lock(mutex_);
+
   ComponentHandle componentHandle = componentDescriptor->getComponentHandle();
   _registryByHandle[componentHandle] = componentDescriptor;
 

packages/react-native/ReactCommon/react/renderer/componentregistry/ComponentDescriptorRegistry.h

@@ -27,7 +27,7 @@ using SharedComponentDescriptorRegistry =
 /*
  * Registry of particular `ComponentDescriptor`s.
  */
-class ComponentDescriptorRegistry {
+class ComponentDescriptorRegistry : public std::enable_shared_from_this<ComponentDescriptorRegistry> {
  public:
   using Shared = std::shared_ptr<const ComponentDescriptorRegistry>;