fix: Reject Promise with timeout if it gets destroyed (#444)

* fix: Reject Promise with timeout if it gets destroyed

If a Promise gets destroyed without ever being resolved or rejected, it goes stale.

This PR fixes this and rejects a Promise with a timeout error if it gets destructed and is still pending

* Add promise typename

* Reject swift promise as well

* Update Promise.hpp

* fix: Build

* Update Dispatcher.cpp

* fix: Also reject `JPromise` if it gets destroyed

packages/react-native-nitro-image/ios/HybridTestObjectSwift.swift

@@ -74,7 +74,7 @@ class HybridTestObjectSwift : HybridTestObjectSwiftKotlinSpec {
   func callSumUpNTimes(callback: @escaping (() -> Promise<Double>), n: Double) throws -> Promise<Double> {
     var result = 0.0
     return Promise.async {
-      for i in 1...Int(n) {
+      for _ in 1...Int(n) {
         let current = try await callback().await()
         result += current
       }

packages/react-native-nitro-modules/android/src/main/cpp/core/JPromise.hpp

@@ -56,6 +56,16 @@ class JPromise final : public jni::HybridClass<JPromise> {
     return newObjectCxxArgs();
   }
 
+public:
+  ~JPromise() override {
+    if (_result == nullptr && _error == nullptr) [[unlikely]] {
+      jni::ThreadScope::WithClassLoader([&]() {
+        std::runtime_error error("Timeouted: JPromise was destroyed!");
+        this->reject(jni::getJavaExceptionForCppException(std::make_exception_ptr(error)));
+      });
+    }
+  }
+
 public:
   void resolve(jni::alias_ref<jni::JObject> result) {
     std::unique_lock lock(_mutex);

packages/react-native-nitro-modules/cpp/core/Promise.hpp

@@ -32,6 +32,14 @@ class Promise final {
 private:
   Promise() {}
 
+public:
+  ~Promise() {
+    if (isPending()) [[unlikely]] {
+      auto message = std::string("Timeouted: Promise<") + TypeInfo::getFriendlyTypename<TResult>() + "> was destroyed!";
+      reject(std::make_exception_ptr(std::runtime_error(message)));
+    }
+  }
+
 public:
   /**
    * Creates a new pending Promise that has to be resolved
@@ -258,6 +266,14 @@ class Promise<void> final {
 private:
   Promise() {}
 
+public:
+  ~Promise() {
+    if (isPending()) [[unlikely]] {
+      std::runtime_error error("Timeouted: Promise<void> was destroyed!");
+      reject(std::make_exception_ptr(std::move(error)));
+    }
+  }
+
 public:
   static std::shared_ptr<Promise> create() {
     return std::shared_ptr<Promise>(new Promise());

packages/react-native-nitro-modules/cpp/threading/Dispatcher.cpp

@@ -1,3 +1,10 @@
+//
+//  Dispatcher.cpp
+//  react-native-nitro
+//
+//  Created by Marc Rousavy on 22.07.24.
+//
+
 #include "Dispatcher.hpp"
 #include "JSIHelpers.hpp"
 #include "NitroDefines.hpp"

packages/react-native-nitro-modules/ios/core/Promise.swift

@@ -37,7 +37,8 @@ public final class Promise<T> {
 
   deinit {
     if state == nil {
-      print("⚠️ Promise<\(String(describing: T.self))> got destroyed, but was never resolved or rejected! It is probably left hanging in JS now.")
+      let message = "Timeouted: Promise<\(String(describing: T.self))> was destroyed!"
+      reject(withError: RuntimeError.error(withMessage: message))
     }
   }