Add support for handling com.facebook.react.bridge.Dynamic as parameter type in TurboModules (#45944)

Summary:
Pull Request resolved: #45944

This diff adds support having (Legacy) Native Modules with functions with parameters of type `Dynamic`.
This is currently blocking some libraries making it harder for them to migrate to New Architecture.

I've implemented it by adding a `DynamicNative` implementation of `Dynamic` which holds a reference of
the payload as a `folly::dynamic`.

Changelog:
[Android] [Added] - Add support for handling `com.facebook.react.bridge.Dynamic` as parameter type in TurboModules

Differential Revision: D60966684

Author: cortinico

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/bridge/DynamicNative.kt

@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.react.bridge
+
+import com.facebook.jni.HybridData
+import com.facebook.proguard.annotations.DoNotStrip
+import com.facebook.proguard.annotations.DoNotStripAny
+
+/**
+ * An implementation of [Dynamic] that has a C++ implementation.
+ *
+ * This is used to support Legacy Native Modules that have not been migrated to the new architecture
+ * and are using [Dynamic] as a parameter type.
+ */
+@DoNotStripAny
+public open class DynamicNative(
+    @Suppress("NoHungarianNotation") @field:DoNotStrip private val mHybridData: HybridData?
+) : Dynamic {
+
+  override val type: ReadableType
+    get() = getTypeNative()
+
+  override val isNull: Boolean
+    get() = isNullNative()
+
+  private external fun getTypeNative(): ReadableType
+
+  private external fun isNullNative(): Boolean
+
+  external override fun asBoolean(): Boolean
+
+  external override fun asInt(): Int
+
+  external override fun asDouble(): Double
+
+  external override fun asString(): String
+
+  external override fun asArray(): ReadableArray
+
+  external override fun asMap(): ReadableMap
+
+  override fun recycle() {
+    // Noop - nothing to recycle since there is no pooling
+  }
+}

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/turbomodule/core/TurboModuleInteropUtils.java

@@ -161,14 +161,11 @@ private static String convertParamClassToJniType(
         || paramClass == Callback.class
         || paramClass == Promise.class
         || paramClass == ReadableMap.class
-        || paramClass == ReadableArray.class) {
+        || paramClass == ReadableArray.class
+        || paramClass == Dynamic.class) {
       return convertClassToJniType(paramClass);
     }
 
-    if (paramClass == Dynamic.class) {
-      // TODO(T145105887): Output warnings that TurboModules doesn't yet support Dynamic arguments
-    }
-
     throw new ParsingException(
         moduleName,
         methodName,

packages/react-native/ReactAndroid/src/main/jni/react/jni/JDynamicNative.cpp

@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include "JDynamicNative.h"
+#include "ReadableNativeArray.h"
+#include "ReadableNativeMap.h"
+
+using namespace facebook::jni;
+
+namespace facebook::react {
+
+jboolean JDynamicNative::isNullNative() {
+  return payload_.isNull();
+}
+
+jni::local_ref<ReadableType> JDynamicNative::getTypeNative() {
+  return ReadableType::getType(payload_.type());
+}
+
+jni::local_ref<jstring> JDynamicNative::asString() {
+  return jni::make_jstring(payload_.asString());
+}
+
+jboolean JDynamicNative::asBoolean() {
+  return payload_.asBool();
+}
+
+jint JDynamicNative::asInt() {
+  return payload_.asInt();
+}
+
+jdouble JDynamicNative::asDouble() {
+  return payload_.asDouble();
+}
+
+jni::local_ref<ReadableArray> JDynamicNative::asArray() {
+  return jni::adopt_local(reinterpret_cast<ReadableArray::javaobject>(
+      ReadableNativeArray::newObjectCxxArgs(payload_).release()));
+}
+
+jni::local_ref<ReadableMap> JDynamicNative::asMap() {
+  return jni::adopt_local(reinterpret_cast<ReadableMap::javaobject>(
+      ReadableNativeMap::createWithContents(std::move(payload_)).release()));
+}
+
+} // namespace facebook::react

packages/react-native/ReactAndroid/src/main/jni/react/jni/JDynamicNative.h

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+#include "NativeCommon.h"
+#include "ReadableNativeArray.h"
+#include "ReadableNativeMap.h"
+
+#include <fbjni/fbjni.h>
+#include <folly/dynamic.h>
+#include <folly/json.h>
+
+namespace facebook::react {
+
+struct JDynamic : public jni::JavaClass<JDynamic> {
+  constexpr static auto kJavaDescriptor = "Lcom/facebook/react/bridge/Dynamic;";
+};
+
+class JDynamicNative : public jni::HybridClass<JDynamicNative, JDynamic> {
+ public:
+  constexpr static auto kJavaDescriptor =
+      "Lcom/facebook/react/bridge/DynamicNative;";
+
+  JDynamicNative(folly::dynamic payload) : payload_(std::move(payload)) {}
+
+  static void registerNatives() {
+    javaClassStatic()->registerNatives(
+        {makeNativeMethod("isNullNative", JDynamicNative::isNullNative),
+         makeNativeMethod("getTypeNative", JDynamicNative::getTypeNative),
+         makeNativeMethod("asInt", JDynamicNative::asInt),
+         makeNativeMethod("asDouble", JDynamicNative::asDouble),
+         makeNativeMethod("asBoolean", JDynamicNative::asBoolean),
+         makeNativeMethod("asString", JDynamicNative::asString),
+         makeNativeMethod("asArray", JDynamicNative::asArray),
+         makeNativeMethod("asMap", JDynamicNative::asMap)});
+  }
+
+ private:
+  friend HybridBase;
+
+  jni::local_ref<ReadableType> getTypeNative();
+  jni::local_ref<jstring> asString();
+  jboolean asBoolean();
+  jint asInt();
+  jdouble asDouble();
+  jboolean isNullNative();
+  jni::local_ref<ReadableArray> asArray();
+  jni::local_ref<ReadableMap> asMap();
+
+  folly::dynamic payload_;
+};
+
+} // namespace facebook::react

packages/react-native/ReactAndroid/src/main/jni/react/jni/OnLoad.cpp

@@ -16,6 +16,7 @@
 #include "CxxModuleWrapperBase.h"
 #include "InspectorNetworkRequestListener.h"
 #include "JCallback.h"
+#include "JDynamicNative.h"
 #include "JInspector.h"
 #include "JReactMarker.h"
 #include "JavaScriptExecutorHolder.h"
@@ -90,6 +91,7 @@ extern "C" JNIEXPORT jint JNI_OnLoad(JavaVM* vm, void* reserved) {
     NativeMap::registerNatives();
     ReadableNativeMap::registerNatives();
     WritableNativeMap::registerNatives();
+    JDynamicNative::registerNatives();
     JReactMarker::registerNatives();
     JInspector::registerNatives();
     ReactInstanceManagerInspectorTarget::registerNatives();

packages/react-native/ReactCommon/react/nativemodule/core/platform/android/ReactCommon/JavaTurboModule.cpp

@@ -21,6 +21,7 @@
 #include <react/bridging/Bridging.h>
 #include <react/debug/react_native_assert.h>
 #include <react/featureflags/ReactNativeFeatureFlags.h>
+#include <react/jni/JDynamicNative.h>
 #include <react/jni/NativeMap.h>
 #include <react/jni/ReadableNativeMap.h>
 #include <react/jni/WritableNativeMap.h>
@@ -364,7 +365,9 @@ JNIArgs convertJSIArgsToJNIArgs(
       continue;
     }
 
-    if (arg->isNull() || arg->isUndefined()) {
+    // Dynamic encapsulates the Null type so we don't want to return null here.
+    if ((arg->isNull() && type != "Lcom/facebook/react/bridge/Dynamic;") ||
+        arg->isUndefined()) {
       jarg->l = nullptr;
     } else if (type == "Ljava/lang/Double;") {
       if (!arg->isNumber()) {
@@ -427,6 +430,10 @@ JNIArgs convertJSIArgsToJNIArgs(
       auto jParams =
           ReadableNativeMap::createWithContents(std::move(dynamicFromValue));
       jarg->l = makeGlobalIfNecessary(jParams.release());
+    } else if (type == "Lcom/facebook/react/bridge/Dynamic;") {
+      auto dynamicFromValue = jsi::dynamicFromValue(rt, *arg);
+      auto jParams = JDynamicNative::newObjectCxxArgs(dynamicFromValue);
+      jarg->l = makeGlobalIfNecessary(jParams.release());
     } else {
       throw JavaTurboModuleInvalidArgumentTypeException(
           type, argIndex, methodName);

packages/react-native/ReactCommon/react/nativemodule/samples/platform/android/SampleLegacyModule.java

@@ -13,12 +13,14 @@
 import com.facebook.proguard.annotations.DoNotStrip;
 import com.facebook.react.bridge.Arguments;
 import com.facebook.react.bridge.Callback;
+import com.facebook.react.bridge.Dynamic;
 import com.facebook.react.bridge.Promise;
 import com.facebook.react.bridge.ReactApplicationContext;
 import com.facebook.react.bridge.ReactContextBaseJavaModule;
 import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.bridge.ReadableMap;
+import com.facebook.react.bridge.ReadableType;
 import com.facebook.react.bridge.WritableArray;
 import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.bridge.WritableNativeArray;
@@ -155,6 +157,57 @@ public WritableMap getUnsafeObject(ReadableMap arg) {
     return map;
   }
 
+  @SuppressWarnings("unused")
+  @ReactMethod(isBlockingSynchronousMethod = true)
+  public WritableMap getDynamic(Dynamic dynamic) {
+    WritableNativeMap resultMap = new WritableNativeMap();
+    ReadableType type = dynamic.getType();
+    switch (type) {
+      case Null -> {
+        log("getDynamic as Null", dynamic, dynamic);
+        resultMap.putString("type", "Null");
+        resultMap.putNull("value");
+        break;
+      }
+      case Boolean -> {
+        boolean result = dynamic.asBoolean();
+        log("getDynamic as Boolean", dynamic, result);
+        resultMap.putString("type", "Boolean");
+        resultMap.putBoolean("value", result);
+        break;
+      }
+      case Number -> {
+        double result = dynamic.asDouble();
+        log("getDynamic as Number", dynamic, result);
+        resultMap.putString("type", "Number");
+        resultMap.putDouble("value", result);
+        break;
+      }
+      case String -> {
+        String result = dynamic.asString();
+        log("getDynamic as String", dynamic, result);
+        resultMap.putString("type", "String");
+        resultMap.putString("value", result);
+        break;
+      }
+      case Array -> {
+        ReadableArray result = dynamic.asArray();
+        log("getDynamic as Array", dynamic, result);
+        resultMap.putString("type", "Array");
+        resultMap.putArray("value", result);
+        break;
+      }
+      case Map -> {
+        ReadableMap result = dynamic.asMap();
+        log("getDynamic as Map", dynamic, result);
+        resultMap.putString("type", "Map");
+        resultMap.putMap("value", result);
+        break;
+      }
+    }
+    return resultMap;
+  }
+
   @DoNotStrip
   @SuppressWarnings("unused")
   @ReactMethod(isBlockingSynchronousMethod = true)

packages/rn-tester/js/examples/TurboModule/SampleLegacyModuleExample.js

@@ -142,6 +142,17 @@ class SampleLegacyModuleExample extends React.Component<{||}, State> {
             getSampleLegacyModule()?.getObject({a: 1, b: 'foo', c: null}),
           getValue: () =>
             getSampleLegacyModule()?.getValue(5, 'test', {a: 1, b: 'foo'}),
+          getDynamicWithNull: () => getSampleLegacyModule()?.getDynamic(null),
+          getDynamicWithBoolean: () =>
+            getSampleLegacyModule()?.getDynamic(true),
+          getDynamicWithNumber: () =>
+            getSampleLegacyModule()?.getDynamic(42.24),
+          getDynamicWithString: () =>
+            getSampleLegacyModule()?.getDynamic('The answer is 42'),
+          getDynamicWithArray: () =>
+            getSampleLegacyModule()?.getDynamic(['the', 'answer', 'is', '42']),
+          getDynamicWithMap: () =>
+            getSampleLegacyModule()?.getDynamic({answer: '42'}),
           callback: () =>
             getSampleLegacyModule()?.getValueWithCallback(callbackValue =>
               this._setResult('callback', callbackValue),