Accept readable Android event payloads

Summary:
Widen Android event payload contracts from `WritableMap` to `ReadableMap` across the event emitters, UI managers and Fabric dispatch pipeline, including `Event.getEventData`. Existing event producers can continue returning writable maps. Build native touch payloads as a complete `folly::dynamic` and return them through `ReadableNativeMap::createWithContents` without constructing and populating a writable Java map.

Document Fabric’s native-backed, consumed-payload contract, update the touch test shadow to return a read-only native map and regenerate the Android API snapshot.

Changelog:
[Android][Breaking] - Change Android event payload APIs from `WritableMap` to `ReadableMap`; update custom emitter and UI manager implementations to match.

Differential Revision: D128208007

Author: javache

packages/react-native/ReactAndroid/api/ReactAndroid.api

@@ -1372,8 +1372,8 @@ public abstract interface class com/facebook/react/bridge/UIManager : com/facebo
 	public abstract fun initialize ()V
 	public abstract fun invalidate ()V
 	public abstract fun markActiveTouchForTag (II)V
-	public abstract fun receiveEvent (IILjava/lang/String;Lcom/facebook/react/bridge/WritableMap;)V
-	public abstract fun receiveEvent (ILjava/lang/String;Lcom/facebook/react/bridge/WritableMap;)V
+	public abstract fun receiveEvent (IILjava/lang/String;Lcom/facebook/react/bridge/ReadableMap;)V
+	public abstract fun receiveEvent (ILjava/lang/String;Lcom/facebook/react/bridge/ReadableMap;)V
 	public abstract fun removeUIManagerEventListener (Lcom/facebook/react/bridge/UIManagerListener;)V
 	public abstract fun resolveCustomDirectEventName (Ljava/lang/String;)Ljava/lang/String;
 	public abstract fun resolveView (I)Landroid/view/View;
@@ -2275,11 +2275,11 @@ public class com/facebook/react/fabric/FabricUIManager : com/facebook/react/brid
 	public fun onRequestEventBeat ()V
 	public fun prependUIBlock (Lcom/facebook/react/fabric/interop/UIBlock;)V
 	public fun profileNextBatch ()V
-	public fun receiveEvent (IILjava/lang/String;Lcom/facebook/react/bridge/WritableMap;)V
-	public fun receiveEvent (IILjava/lang/String;ZLcom/facebook/react/bridge/WritableMap;I)V
-	public fun receiveEvent (IILjava/lang/String;ZLcom/facebook/react/bridge/WritableMap;IZ)V
-	public fun receiveEvent (IILjava/lang/String;ZLcom/facebook/react/bridge/WritableMap;IZJ)V
-	public fun receiveEvent (ILjava/lang/String;Lcom/facebook/react/bridge/WritableMap;)V
+	public fun receiveEvent (IILjava/lang/String;Lcom/facebook/react/bridge/ReadableMap;)V
+	public fun receiveEvent (IILjava/lang/String;ZLcom/facebook/react/bridge/ReadableMap;I)V
+	public fun receiveEvent (IILjava/lang/String;ZLcom/facebook/react/bridge/ReadableMap;IZ)V
+	public fun receiveEvent (IILjava/lang/String;ZLcom/facebook/react/bridge/ReadableMap;IZJ)V
+	public fun receiveEvent (ILjava/lang/String;Lcom/facebook/react/bridge/ReadableMap;)V
 	public fun removeUIManagerEventListener (Lcom/facebook/react/bridge/UIManagerListener;)V
 	public fun resolveCustomDirectEventName (Ljava/lang/String;)Ljava/lang/String;
 	public fun resolveView (I)Landroid/view/View;
@@ -3503,6 +3503,7 @@ public final class com/facebook/react/uimanager/NativeViewHierarchyOptimizer {
 
 public final class com/facebook/react/uimanager/OnLayoutEvent : com/facebook/react/uimanager/events/Event {
 	public static final field Companion Lcom/facebook/react/uimanager/OnLayoutEvent$Companion;
+	public synthetic fun getEventData ()Lcom/facebook/react/bridge/ReadableMap;
 	public fun getEventName ()Ljava/lang/String;
 	public static final fun obtain (IIIII)Lcom/facebook/react/uimanager/OnLayoutEvent;
 	public static final fun obtain (IIIIII)Lcom/facebook/react/uimanager/OnLayoutEvent;
@@ -4275,8 +4276,8 @@ public class com/facebook/react/uimanager/UIManagerModule : com/facebook/react/b
 	public fun onHostResume ()V
 	public fun prependUIBlock (Lcom/facebook/react/uimanager/UIBlock;)V
 	public fun profileNextBatch ()V
-	public fun receiveEvent (IILjava/lang/String;Lcom/facebook/react/bridge/WritableMap;)V
-	public fun receiveEvent (ILjava/lang/String;Lcom/facebook/react/bridge/WritableMap;)V
+	public fun receiveEvent (IILjava/lang/String;Lcom/facebook/react/bridge/ReadableMap;)V
+	public fun receiveEvent (ILjava/lang/String;Lcom/facebook/react/bridge/ReadableMap;)V
 	public fun removeRootView (I)V
 	public fun removeUIManagerEventListener (Lcom/facebook/react/bridge/UIManagerListener;)V
 	public fun resolveCustomDirectEventName (Ljava/lang/String;)Ljava/lang/String;
@@ -4679,6 +4680,7 @@ public abstract interface class com/facebook/react/uimanager/events/BatchEventDi
 public final class com/facebook/react/uimanager/events/ContentSizeChangeEvent : com/facebook/react/uimanager/events/Event {
 	public fun <init> (III)V
 	public fun <init> (IIII)V
+	public synthetic fun getEventData ()Lcom/facebook/react/bridge/ReadableMap;
 	public fun getEventName ()Ljava/lang/String;
 }
 
@@ -4695,7 +4697,7 @@ public abstract class com/facebook/react/uimanager/events/Event {
 	public fun getCoalescingKey ()S
 	public fun getEventAnimationDriverMatchSpec ()Lcom/facebook/react/uimanager/events/Event$EventAnimationDriverMatchSpec;
 	protected fun getEventCategory ()I
-	protected fun getEventData ()Lcom/facebook/react/bridge/WritableMap;
+	protected fun getEventData ()Lcom/facebook/react/bridge/ReadableMap;
 	public abstract fun getEventName ()Ljava/lang/String;
 	public final fun getSurfaceId ()I
 	public final fun getTimestampMs ()J
@@ -4734,7 +4736,7 @@ public final class com/facebook/react/uimanager/events/NativeGestureUtil {
 }
 
 public abstract interface class com/facebook/react/uimanager/events/RCTEventEmitter : com/facebook/react/bridge/JavaScriptModule {
-	public abstract fun receiveEvent (ILjava/lang/String;Lcom/facebook/react/bridge/WritableMap;)V
+	public abstract fun receiveEvent (ILjava/lang/String;Lcom/facebook/react/bridge/ReadableMap;)V
 	public fun receiveTouches (Ljava/lang/String;Lcom/facebook/react/bridge/WritableArray;Lcom/facebook/react/bridge/WritableArray;)V
 }
 
@@ -4743,16 +4745,16 @@ public final class com/facebook/react/uimanager/events/RCTEventEmitter$DefaultIm
 }
 
 public abstract interface class com/facebook/react/uimanager/events/RCTModernEventEmitter : com/facebook/react/uimanager/events/RCTEventEmitter {
-	public fun receiveEvent (IILjava/lang/String;Lcom/facebook/react/bridge/WritableMap;)V
-	public abstract fun receiveEvent (IILjava/lang/String;ZILcom/facebook/react/bridge/WritableMap;I)V
-	public fun receiveEvent (IILjava/lang/String;ZILcom/facebook/react/bridge/WritableMap;IJ)V
-	public fun receiveEvent (ILjava/lang/String;Lcom/facebook/react/bridge/WritableMap;)V
+	public fun receiveEvent (IILjava/lang/String;Lcom/facebook/react/bridge/ReadableMap;)V
+	public abstract fun receiveEvent (IILjava/lang/String;ZILcom/facebook/react/bridge/ReadableMap;I)V
+	public fun receiveEvent (IILjava/lang/String;ZILcom/facebook/react/bridge/ReadableMap;IJ)V
+	public fun receiveEvent (ILjava/lang/String;Lcom/facebook/react/bridge/ReadableMap;)V
 }
 
 public final class com/facebook/react/uimanager/events/RCTModernEventEmitter$DefaultImpls {
-	public static fun receiveEvent (Lcom/facebook/react/uimanager/events/RCTModernEventEmitter;IILjava/lang/String;Lcom/facebook/react/bridge/WritableMap;)V
-	public static fun receiveEvent (Lcom/facebook/react/uimanager/events/RCTModernEventEmitter;IILjava/lang/String;ZILcom/facebook/react/bridge/WritableMap;IJ)V
-	public static fun receiveEvent (Lcom/facebook/react/uimanager/events/RCTModernEventEmitter;ILjava/lang/String;Lcom/facebook/react/bridge/WritableMap;)V
+	public static fun receiveEvent (Lcom/facebook/react/uimanager/events/RCTModernEventEmitter;IILjava/lang/String;Lcom/facebook/react/bridge/ReadableMap;)V
+	public static fun receiveEvent (Lcom/facebook/react/uimanager/events/RCTModernEventEmitter;IILjava/lang/String;ZILcom/facebook/react/bridge/ReadableMap;IJ)V
+	public static fun receiveEvent (Lcom/facebook/react/uimanager/events/RCTModernEventEmitter;ILjava/lang/String;Lcom/facebook/react/bridge/ReadableMap;)V
 	public static fun receiveTouches (Lcom/facebook/react/uimanager/events/RCTModernEventEmitter;Ljava/lang/String;Lcom/facebook/react/bridge/WritableArray;Lcom/facebook/react/bridge/WritableArray;)V
 }
 
@@ -5238,6 +5240,7 @@ public final class com/facebook/react/views/image/ImageLoadEvent : com/facebook/
 	public static final fun createProgressEvent (ILjava/lang/String;II)Lcom/facebook/react/views/image/ImageLoadEvent;
 	public static final fun eventNameForType (I)Ljava/lang/String;
 	public fun getCoalescingKey ()S
+	public synthetic fun getEventData ()Lcom/facebook/react/bridge/ReadableMap;
 	public fun getEventName ()Ljava/lang/String;
 }
 
@@ -5924,6 +5927,7 @@ public final class com/facebook/react/views/scroll/ReactScrollViewManager$Compan
 public final class com/facebook/react/views/scroll/ScrollEvent : com/facebook/react/uimanager/events/Event {
 	public static final field Companion Lcom/facebook/react/views/scroll/ScrollEvent$Companion;
 	public fun canCoalesce ()Z
+	public synthetic fun getEventData ()Lcom/facebook/react/bridge/ReadableMap;
 	public fun getEventName ()Ljava/lang/String;
 	public static final fun obtain (IILcom/facebook/react/views/scroll/ScrollEventType;FFFFIIII)Lcom/facebook/react/views/scroll/ScrollEvent;
 	public static final fun obtain (ILcom/facebook/react/views/scroll/ScrollEventType;FFFFIIII)Lcom/facebook/react/views/scroll/ScrollEvent;

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/animated/EventAnimationDriver.kt

@@ -11,7 +11,6 @@ import com.facebook.react.bridge.ReadableArray
 import com.facebook.react.bridge.ReadableMap
 import com.facebook.react.bridge.ReadableType
 import com.facebook.react.bridge.UnexpectedNativeTypeException
-import com.facebook.react.bridge.WritableMap
 import com.facebook.react.uimanager.events.EventCategoryDef
 import com.facebook.react.uimanager.events.RCTModernEventEmitter
 
@@ -29,7 +28,7 @@ internal class EventAnimationDriver(
       eventName: String,
       canCoalesceEvent: Boolean,
       customCoalesceKey: Int,
-      params: WritableMap?,
+      params: ReadableMap?,
       @EventCategoryDef category: Int,
   ) {
     requireNotNull(params) { "Native animated events must have event data." }

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

@@ -25,7 +25,7 @@ public interface UIManager : PerformanceCounter {
   @ThreadConfined(ThreadConfined.UI)
   @Deprecated(
       "This legacy surface API will be removed in a future release. " +
-          "Use ReactHost.createSurface(...) and ReactSurface.start() instead."
+          "Use ReactHost.createSurface(...) and ReactSurface.start() instead.",
   )
   public fun <T : View> addRootView(rootView: T, initialProps: WritableMap?): Int
 
@@ -37,7 +37,7 @@ public interface UIManager : PerformanceCounter {
   @AnyThread
   @Deprecated(
       "This legacy surface API will be removed in a future release. " +
-          "Use ReactHost.createSurface(...) and ReactSurface.start() instead."
+          "Use ReactHost.createSurface(...) and ReactSurface.start() instead.",
   )
   public fun <T : View?> startSurface(
       rootView: T,
@@ -55,7 +55,7 @@ public interface UIManager : PerformanceCounter {
    */
   @AnyThread
   @Deprecated(
-      "This legacy surface API will be removed in a future release. Use ReactSurface.stop() instead."
+      "This legacy surface API will be removed in a future release. Use ReactSurface.stop() instead.",
   )
   public fun stopSurface(surfaceId: Int)
 
@@ -156,10 +156,11 @@ public interface UIManager : PerformanceCounter {
    *
    * @param reactTag tag
    * @param eventName name of the event
-   * @param event parameters
+   * @param event native-backed event parameters; Fabric consumes the payload during dispatch, so it
+   *   must not be reused afterwards
    */
   @Deprecated("", ReplaceWith("receiveEvent(surfaceId, reactTag, eventName, event)"))
-  public fun receiveEvent(reactTag: Int, eventName: String, event: WritableMap?)
+  public fun receiveEvent(reactTag: Int, eventName: String, event: ReadableMap?)
 
   /**
    * This method dispatches events from RN Android code to JS. The delivery of this event will not
@@ -168,9 +169,10 @@ public interface UIManager : PerformanceCounter {
    * @param surfaceId
    * @param reactTag tag
    * @param eventName name of the event
-   * @param event parameters
+   * @param event native-backed event parameters; Fabric consumes the payload during dispatch, so it
+   *   must not be reused afterwards
    */
-  public fun receiveEvent(surfaceId: Int, reactTag: Int, eventName: String, event: WritableMap?)
+  public fun receiveEvent(surfaceId: Int, reactTag: Int, eventName: String, event: ReadableMap?)
 
   /** Resolves Direct Event name exposed to JS from the one known to the Native side. */
   @Deprecated("") public fun resolveCustomDirectEventName(eventName: String): String?

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/fabric/FabricUIManager.java

@@ -1180,14 +1180,14 @@ public void updateRootLayoutSpecs(
 
   @Deprecated
   @Override
-  public void receiveEvent(int reactTag, String eventName, @Nullable WritableMap params) {
+  public void receiveEvent(int reactTag, String eventName, @Nullable ReadableMap params) {
     receiveEvent(View.NO_ID, reactTag, eventName, false, params, EventCategoryDef.UNSPECIFIED);
   }
 
   @Deprecated
   @Override
   public void receiveEvent(
-      int surfaceId, int reactTag, String eventName, @Nullable WritableMap params) {
+      int surfaceId, int reactTag, String eventName, @Nullable ReadableMap params) {
     receiveEvent(surfaceId, reactTag, eventName, false, params, EventCategoryDef.UNSPECIFIED);
   }
 
@@ -1212,7 +1212,7 @@ public void receiveEvent(
       int reactTag,
       String eventName,
       boolean canCoalesceEvent,
-      @Nullable WritableMap params,
+      @Nullable ReadableMap params,
       @EventCategoryDef int eventCategory) {
     receiveEvent(
         surfaceId,
@@ -1248,7 +1248,7 @@ public void receiveEvent(
       int reactTag,
       String eventName,
       boolean canCoalesceEvent,
-      @Nullable WritableMap params,
+      @Nullable ReadableMap params,
       @EventCategoryDef int eventCategory,
       boolean experimentalIsSynchronous) {
     receiveEvent(
@@ -1284,7 +1284,7 @@ public void receiveEvent(
       int reactTag,
       String eventName,
       boolean canCoalesceEvent,
-      @Nullable WritableMap params,
+      @Nullable ReadableMap params,
       @EventCategoryDef int eventCategory,
       boolean experimentalIsSynchronous,
       long eventTimestamp) {

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/fabric/events/EventEmitterWrapper.kt

@@ -11,8 +11,8 @@ import android.annotation.SuppressLint
 import com.facebook.jni.HybridClassBase
 import com.facebook.proguard.annotations.DoNotStripAny
 import com.facebook.react.bridge.NativeMap
+import com.facebook.react.bridge.ReadableMap
 import com.facebook.react.bridge.UiThreadUtil
-import com.facebook.react.bridge.WritableMap
 import com.facebook.react.fabric.FabricSoLoader.staticInit
 import com.facebook.react.uimanager.events.EventCategoryDef
 
@@ -46,14 +46,14 @@ internal class EventEmitterWrapper private constructor() : HybridClassBase() {
    * Invokes the execution of the C++ EventEmitter.
    *
    * @param eventName [String] name of the event to execute.
-   * @param params [WritableMap] payload of the event
+   * @param params [ReadableMap] payload of the event
    * @param eventCategory event category
    * @param eventTimestamp timestamp when the event was triggered (in milliseconds since boot)
    */
   @Synchronized
   fun dispatch(
       eventName: String,
-      params: WritableMap?,
+      params: ReadableMap?,
       @EventCategoryDef eventCategory: Int,
       eventTimestamp: Long,
   ) {
@@ -64,7 +64,7 @@ internal class EventEmitterWrapper private constructor() : HybridClassBase() {
   }
 
   @Synchronized
-  fun dispatchEventSynchronously(eventName: String, params: WritableMap?, eventTimestamp: Long) {
+  fun dispatchEventSynchronously(eventName: String, params: ReadableMap?, eventTimestamp: Long) {
     if (!isValid) {
       return
     }
@@ -77,11 +77,11 @@ internal class EventEmitterWrapper private constructor() : HybridClassBase() {
    * target.
    *
    * @param eventName [String] name of the event to execute.
-   * @param params [WritableMap] payload of the event
+   * @param params [ReadableMap] payload of the event
    * @param eventTimestamp timestamp when the event was triggered (in milliseconds since boot)
    */
   @Synchronized
-  fun dispatchUnique(eventName: String, params: WritableMap?, eventTimestamp: Long) {
+  fun dispatchUnique(eventName: String, params: ReadableMap?, eventTimestamp: Long) {
     if (!isValid) {
       return
     }

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/fabric/events/FabricEventEmitter.kt

@@ -8,7 +8,7 @@
 package com.facebook.react.fabric.events
 
 import android.os.SystemClock
-import com.facebook.react.bridge.WritableMap
+import com.facebook.react.bridge.ReadableMap
 import com.facebook.react.fabric.FabricUIManager
 import com.facebook.react.uimanager.events.EventCategoryDef
 import com.facebook.react.uimanager.events.RCTModernEventEmitter
@@ -22,7 +22,7 @@ internal class FabricEventEmitter(private val uiManager: FabricUIManager) : RCTM
       eventName: String,
       canCoalesceEvent: Boolean,
       customCoalesceKey: Int,
-      params: WritableMap?,
+      params: ReadableMap?,
       @EventCategoryDef category: Int,
   ) {
     receiveEvent(
@@ -43,7 +43,7 @@ internal class FabricEventEmitter(private val uiManager: FabricUIManager) : RCTM
       eventName: String,
       canCoalesceEvent: Boolean,
       customCoalesceKey: Int,
-      params: WritableMap?,
+      params: ReadableMap?,
       @EventCategoryDef category: Int,
       eventTimestamp: Long,
   ) {

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/fabric/mounting/MountingManager.kt

@@ -18,7 +18,6 @@ import com.facebook.react.bridge.ReadableArray
 import com.facebook.react.bridge.ReadableMap
 import com.facebook.react.bridge.RetryableMountingLayerException
 import com.facebook.react.bridge.UiThreadUtil.assertOnUiThread
-import com.facebook.react.bridge.WritableMap
 import com.facebook.react.fabric.events.EventEmitterWrapper
 import com.facebook.react.fabric.mounting.mountitems.MountItem
 import com.facebook.react.touch.JSResponderHandler
@@ -342,7 +341,7 @@ internal class MountingManager(
       reactTag: Int,
       eventName: String,
       canCoalesceEvent: Boolean,
-      params: WritableMap?,
+      params: ReadableMap?,
       @EventCategoryDef eventCategory: Int,
       eventTimestamp: Long,
   ) {

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/fabric/mounting/SurfaceMountingManager.kt

@@ -1171,7 +1171,7 @@ internal constructor(
       reactTag: Int,
       eventName: String,
       canCoalesceEvent: Boolean,
-      params: WritableMap?,
+      params: ReadableMap?,
       @EventCategoryDef eventCategory: Int,
       eventTimestamp: Long,
   ) {
@@ -1252,7 +1252,7 @@ internal constructor(
 
   private class PendingViewEvent(
       private val eventName: String,
-      private val params: WritableMap?,
+      private val params: ReadableMap?,
       @field:EventCategoryDef private val eventCategory: Int,
       private val canCoalesceEvent: Boolean,
       private val eventTimestamp: Long,

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/interop/InteropEvent.kt

@@ -7,7 +7,7 @@
 
 package com.facebook.react.internal.interop
 
-import com.facebook.react.bridge.WritableMap
+import com.facebook.react.bridge.ReadableMap
 import com.facebook.react.common.annotations.internal.InteropLegacyArchitecture
 import com.facebook.react.common.annotations.internal.LegacyArchitectureLogger
 import com.facebook.react.uimanager.events.Event
@@ -20,14 +20,14 @@ import com.facebook.react.uimanager.events.Event
 @InteropLegacyArchitecture
 internal class InteropEvent(
     @get:JvmName("eventName") val interopEventName: String,
-    @get:JvmName("eventData") val eventData: WritableMap?,
+    @get:JvmName("eventData") val eventData: ReadableMap?,
     surfaceId: Int,
     viewTag: Int,
 ) : Event<InteropEvent>(surfaceId, viewTag) {
 
   override fun getEventName(): String = interopEventName
 
-  override fun getEventData(): WritableMap? = eventData
+  override fun getEventData(): ReadableMap? = eventData
 
   private companion object {
     init {

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/interop/InteropEventEmitter.kt

@@ -10,7 +10,7 @@
 package com.facebook.react.internal.interop
 
 import com.facebook.react.bridge.ReactContext
-import com.facebook.react.bridge.WritableMap
+import com.facebook.react.bridge.ReadableMap
 import com.facebook.react.common.annotations.VisibleForTesting
 import com.facebook.react.common.annotations.internal.InteropLegacyArchitecture
 import com.facebook.react.common.annotations.internal.LegacyArchitectureLogger
@@ -34,7 +34,7 @@ internal class InteropEventEmitter(private val reactContext: ReactContext) : RCT
   private var eventDispatcherOverride: EventDispatcher? = null
 
   @Deprecated("Deprecated in Java")
-  override fun receiveEvent(targetTag: Int, eventName: String, params: WritableMap?) {
+  override fun receiveEvent(targetTag: Int, eventName: String, params: ReadableMap?) {
     val dispatcher = eventDispatcherOverride ?: UIManagerHelper.getEventDispatcher(reactContext)
     val surfaceId = UIManagerHelper.getSurfaceId(reactContext)
     dispatcher?.dispatchEvent(InteropEvent(eventName, params, surfaceId, targetTag))