chore: Add tests for verifying Java GC leaks

example/ios/Podfile.lock

@@ -2217,7 +2217,7 @@ EXTERNAL SOURCES:
 
 SPEC CHECKSUMS:
   FBLazyVector: 7c1d69992204c5ec452eeefa4a24b0ff311709c8
-  hermes-engine: 16e781d7fca74c8bb3ca59b99527d9633ee9ee36
+  hermes-engine: b69aade2dcf59e8c2203c748ca79c7fa4c875053
   NitroModules: ea6ec1c94ca32c73b22d726b113e570d2abc8b5d
   NitroTest: cbbc53e62ed086d1993bbac0fcec3cc77c0b4617
   NitroTestExternal: 31816d957144245da0b24b4f95fb3427533e73d7
@@ -2229,7 +2229,7 @@ SPEC CHECKSUMS:
   React: f6f8fc5c01e77349cdfaf49102bcb928ac31d8ed
   React-callinvoker: 3e62a849bda1522c6422309c02f5dc3210bc5359
   React-Core: 0b765bc7c2b83dff178c2b03ed8a0390df26f18c
-  React-Core-prebuilt: 88810feb58457484bff17e9e91a15453407d745a
+  React-Core-prebuilt: 1ed3b91c7035f715bf741f1b8a2c87e94d126d38
   React-CoreModules: 55b932564ba696301cb683a86385be6a6f137e57
   React-cxxreact: 5bfb95256fde56cc0f9ce425f38cfaa085e71ad2
   React-debug: f9dda2791d3ebe2078bc6102641edab77917efb7
@@ -2292,7 +2292,7 @@ SPEC CHECKSUMS:
   ReactAppDependencyProvider: 23e2bca1661f8781e55fcc05a151fc1df97bc1fb
   ReactCodegen: c049d7e966ed24be56d8e21cb1b8880316975e76
   ReactCommon: 89ccc6cb100ca5a0303b46483037ef8f3e06e2e0
-  ReactNativeDependencies: 1a7e3c3ffa57533d8118dd9bc01790ffa9e02a3b
+  ReactNativeDependencies: 69de62c8a59d21e7b6af8bdfb62b61e798f65351
   RNScreens: dd61bc3a3e6f6901ad833efa411917d44827cf51
   Yoga: 21f482cbc18b56cdc477cd3a0c5b8c2c83ac27ce
 

example/src/getTests.ts

@@ -193,7 +193,7 @@ export function getTests(
 ): TestRunner[] {
   const backend = options.backend ?? throwingBackend
   const { it } = createTestRunner(backend)
-  const createTest = createCreateTest(it)
+  const createTest = createCreateTest()
 
   return [
     // Basic prototype tests
@@ -1478,6 +1478,55 @@ export function getTests(
         .didNotThrow()
         .equals(10_000)
     ),
+    createTest('HybridObjects dont leak memory', () =>
+      it(() => {
+        const baselineAllocations =
+          NitroModules.debug_getTotalAllocatedHybridObjects()
+
+        const BATCH_SIZE = 1000
+        const LOOP_COUNT = 10
+        const TOTAL_ALLOCATIONS = BATCH_SIZE * LOOP_COUNT
+
+        const objects: Array<TestObjectCpp | TestObjectSwiftKotlin> = []
+        for (let i = 0; i < TOTAL_ALLOCATIONS; i++) {
+          const object = testObject.newTestObject()
+          object.numberValue = i
+          objects.push(object)
+
+          if (objects.length >= BATCH_SIZE) {
+            objects.length = 0
+            gc()
+          }
+        }
+
+        objects.length = 0
+        gc()
+        gc()
+        gc()
+
+        const currentAllocations =
+          NitroModules.debug_getTotalAllocatedHybridObjects()
+        const remainingAllocations = currentAllocations - baselineAllocations
+        // make sure that less than 10% of the total allocations are remaining, indicating GC ran for most of it.
+        const didDeleteMostObjects =
+          remainingAllocations < TOTAL_ALLOCATIONS * 0.1
+        const result: {
+          baselineAllocations: number
+          currentAllocations: number
+          isEqual?: boolean
+        } = {
+          baselineAllocations: baselineAllocations,
+          currentAllocations: currentAllocations,
+          isEqual: didDeleteMostObjects,
+        }
+        if (!didDeleteMostObjects) {
+          delete result.isEqual
+        }
+        return result
+      })
+        .didNotThrow()
+        .toContain('isEqual')
+    ),
     createTest('callWithOptional(undefined)', async () =>
       (
         await it<number | undefined>(() => {

packages/react-native-nitro-modules/cpp/core/HybridObject.cpp

@@ -4,12 +4,23 @@
 
 #include "HybridObject.hpp"
 #include "CommonGlobals.hpp"
+#include "HybridNitroModulesProxy.hpp"
 #include "JSIConverter.hpp"
 #include "NitroDefines.hpp"
 
 namespace margelo::nitro {
 
-HybridObject::HybridObject(const char* NON_NULL name) : HybridObjectPrototype(), _name(name) {}
+HybridObject::HybridObject(const char* NON_NULL name) : HybridObjectPrototype(), _name(name) {
+#ifdef NITRO_DEBUG
+  HybridNitroModulesProxy::debug_notifyHybridObjectAllocated();
+#endif
+}
+
+HybridObject::~HybridObject() {
+#ifdef NITRO_DEBUG
+  HybridNitroModulesProxy::debug_notifyHybridObjectDeallocated();
+#endif
+}
 
 std::string HybridObject::toString() {
   return "[HybridObject " + std::string(_name) + "]";

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

@@ -35,7 +35,7 @@ class HybridObject : public virtual jsi::NativeState, public HybridObjectPrototy
    * Called when no more references to the given `HybridObject` exist in both C++ and JS.
    * JS might keep references for longer, as it is a garbage collected language.
    */
-  ~HybridObject() override = default;
+  ~HybridObject() override;
   /**
    * HybridObjects cannot be copied.
    */

packages/react-native-nitro-modules/cpp/entrypoint/HybridNitroModulesProxy.cpp

@@ -29,6 +29,8 @@ void HybridNitroModulesProxy::loadHybridMethods() {
 
     prototype.registerHybridGetter("buildType", &HybridNitroModulesProxy::getBuildType);
     prototype.registerHybridGetter("version", &HybridNitroModulesProxy::getVersion);
+
+    prototype.registerHybridMethod("debug_getTotalAllocatedHybridObjects", &HybridNitroModulesProxy::debug_getTotalAllocatedHybridObjects);
   });
 }
 
@@ -94,4 +96,19 @@ std::string HybridNitroModulesProxy::getVersion() {
   return NITRO_VERSION;
 }
 
+// Allocation tests
+static std::atomic_size_t _hybridObjectInstancesCount{0};
+double HybridNitroModulesProxy::debug_getTotalAllocatedHybridObjects() {
+  size_t count = _hybridObjectInstancesCount.load(std::memory_order_relaxed);
+  return static_cast<double>(count);
+}
+
+void HybridNitroModulesProxy::debug_notifyHybridObjectAllocated() {
+  _hybridObjectInstancesCount.fetch_add(1, std::memory_order_relaxed);
+}
+
+void HybridNitroModulesProxy::debug_notifyHybridObjectDeallocated() {
+  _hybridObjectInstancesCount.fetch_sub(1, std::memory_order_relaxed);
+}
+
 } // namespace margelo::nitro

packages/react-native-nitro-modules/cpp/entrypoint/HybridNitroModulesProxy.hpp

@@ -46,6 +46,11 @@ class HybridNitroModulesProxy final : public HybridObject {
   std::string getBuildType();
   std::string getVersion();
 
+  // Allocation tests
+  double debug_getTotalAllocatedHybridObjects();
+  static void debug_notifyHybridObjectAllocated();
+  static void debug_notifyHybridObjectDeallocated();
+
 private:
   static constexpr auto TAG = "NitroModulesProxy";
 };

packages/react-native-nitro-modules/src/NitroModulesProxy.ts

@@ -93,4 +93,10 @@ export interface NitroModulesProxy
    * owns it - not JS.
    */
   createNativeArrayBuffer(size: number): ArrayBuffer
+
+  /**
+   * Gets a total number of currently allocated {@linkcode HybridObject}s.
+   * @internal
+   */
+  debug_getTotalAllocatedHybridObjects(): number
 }