fix: report correct selection in Android onChange event during autofill

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactEditText.kt

@@ -37,9 +37,11 @@ import android.view.MotionEvent
 import android.view.View
 import android.view.ViewGroup
 import android.view.accessibility.AccessibilityNodeInfo
+import android.view.autofill.AutofillValue
 import android.view.inputmethod.EditorInfo
 import android.view.inputmethod.InputConnection
 import android.view.inputmethod.InputMethodManager
+import androidx.annotation.RequiresApi
 import androidx.appcompat.widget.AppCompatEditText
 import androidx.core.graphics.withTranslation
 import androidx.core.util.Predicate
@@ -147,6 +149,12 @@ public open class ReactEditText public constructor(context: Context) : AppCompat
   internal var disableTextDiffing: Boolean = false
   protected var isSettingTextFromState: Boolean = false
 
+  // TextView.autofill() sets the new text (notifying the TextWatchers) before it moves the
+  // cursor to the end of the text, so watchers reading the selection while an autofill is in
+  // progress would see a stale position.
+  internal var isBeingAutofilled: Boolean = false
+    private set
+
   private var eventDispatcher: EventDispatcher? = null
 
   private var textWatcherDelegator: TextWatcherDelegator? = null
@@ -339,6 +347,16 @@ public open class ReactEditText public constructor(context: Context) : AppCompat
     // We don't call super.setLineHeight() because LineHeight is fully managed by ReactNative
   }
 
+  @RequiresApi(Build.VERSION_CODES.O)
+  override fun autofill(value: AutofillValue) {
+    isBeingAutofilled = true
+    try {
+      super.autofill(value)
+    } finally {
+      isBeingAutofilled = false
+    }
+  }
+
   override fun onScrollChanged(horiz: Int, vert: Int, oldHoriz: Int, oldVert: Int) {
     super.onScrollChanged(horiz, vert, oldHoriz, oldVert)
     scrollWatcher?.onScrollChanged(horiz, vert, oldHoriz, oldVert)

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactTextInputTextWatcher.kt

@@ -18,8 +18,9 @@ import com.facebook.react.uimanager.events.EventDispatcher
 internal class ReactTextInputTextWatcher(
     reactContext: ReactContext,
     private val editText: ReactEditText,
+    private val eventDispatcher: EventDispatcher? =
+        UIManagerHelper.getEventDispatcher(reactContext),
 ) : TextWatcher {
-  private val eventDispatcher: EventDispatcher? = UIManagerHelper.getEventDispatcher(reactContext)
   private val surfaceId = UIManagerHelper.getSurfaceId(reactContext)
   private var previousText: String? = null
 
@@ -55,15 +56,20 @@ internal class ReactTextInputTextWatcher(
       stateWrapper.updateState(newStateData)
     }
 
+    // While an autofill is in progress the cursor still sits at its pre-autofill position;
+    // TextView.autofill() moves it to the end of the text only after this watcher has run.
+    val selectionStart = if (editText.isBeingAutofilled) s.length else editText.selectionStart
+    val selectionEnd = if (editText.isBeingAutofilled) s.length else editText.selectionEnd
+
     // The event that contains the event counter and updates it must be sent first.
     eventDispatcher?.dispatchEvent(
         ReactTextChangedEvent(
             surfaceId,
             editText.id,
             s.toString(),
             editText.incrementAndGetEventCounter(),
-            editText.selectionStart,
-            editText.selectionEnd,
+            selectionStart,
+            selectionEnd,
         )
     )
   }

packages/react-native/ReactAndroid/src/test/java/com/facebook/react/views/textinput/ReactTextInputTextWatcherTest.kt

@@ -0,0 +1,101 @@
+/*
+ * 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.
+ */
+
+// TODO T207169925: Migrate CatalystInstance to Reacthost and remove the Suppress("DEPRECATION")
+// annotation
+@file:Suppress("DEPRECATION")
+
+package com.facebook.react.views.textinput
+
+import android.util.DisplayMetrics
+import android.view.autofill.AutofillValue
+import androidx.core.content.res.ResourcesCompat.ID_NULL
+import com.facebook.react.bridge.BridgeReactContext
+import com.facebook.react.bridge.CatalystInstance
+import com.facebook.react.bridge.ReactTestHelper.createMockCatalystInstance
+import com.facebook.react.bridge.WritableMap
+import com.facebook.react.internal.featureflags.ReactNativeFeatureFlagsForTests
+import com.facebook.react.uimanager.DisplayMetricsHolder
+import com.facebook.react.uimanager.ThemedReactContext
+import com.facebook.testutils.fakes.FakeEventDispatcher
+import com.facebook.testutils.shadows.ShadowArguments
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.RuntimeEnvironment
+import org.robolectric.annotation.Config
+
+/**
+ * Verify the selection reported in {@link ReactTextChangedEvent}s emitted by {@link
+ * ReactTextInputTextWatcher}
+ */
+@RunWith(RobolectricTestRunner::class)
+@Config(shadows = [ShadowArguments::class])
+class ReactTextInputTextWatcherTest {
+
+  private lateinit var context: BridgeReactContext
+  private lateinit var catalystInstanceMock: CatalystInstance
+  private lateinit var themedContext: ThemedReactContext
+  private lateinit var manager: ReactTextInputManager
+  private lateinit var view: ReactEditText
+  private lateinit var eventDispatcher: FakeEventDispatcher
+
+  @Before
+  fun setup() {
+    ReactNativeFeatureFlagsForTests.setUp()
+    context = BridgeReactContext(RuntimeEnvironment.getApplication())
+    catalystInstanceMock = createMockCatalystInstance()
+    context.initializeWithInstance(catalystInstanceMock)
+    themedContext = ThemedReactContext(context, context.baseContext, null, ID_NULL)
+    manager = ReactTextInputManager()
+    DisplayMetricsHolder.setScreenDisplayMetrics(DisplayMetrics())
+    view = manager.createViewInstance(themedContext)
+    eventDispatcher = FakeEventDispatcher()
+    view.addTextChangedListener(ReactTextInputTextWatcher(themedContext, view, eventDispatcher))
+  }
+
+  @Test
+  fun testAutofillReportsSelectionAtEndOfText() {
+    val autofilledText = "+15551234567"
+
+    view.autofill(AutofillValue.forText(autofilledText))
+
+    // The framework moves the cursor to the end of the text after autofilling
+    assertThat(view.selectionStart).isEqualTo(autofilledText.length)
+    assertThat(view.selectionEnd).isEqualTo(autofilledText.length)
+
+    val eventData = lastTextChangedEventData()
+    assertThat(eventData.getString("text")).isEqualTo(autofilledText)
+    val selection = checkNotNull(eventData.getMap("selection"))
+    assertThat(selection.getInt("start")).isEqualTo(autofilledText.length)
+    assertThat(selection.getInt("end")).isEqualTo(autofilledText.length)
+  }
+
+  @Test
+  fun testTextInsertedAtCursorReportsSelectionAfterInsertedText() {
+    view.setText("+1555123")
+    view.setSelection(8)
+
+    // Mimics pasting/typing "4567" at the cursor position
+    checkNotNull(view.text).insert(8, "4567")
+
+    val eventData = lastTextChangedEventData()
+    assertThat(eventData.getString("text")).isEqualTo("+15551234567")
+    val selection = checkNotNull(eventData.getMap("selection"))
+    assertThat(selection.getInt("start")).isEqualTo(12)
+    assertThat(selection.getInt("end")).isEqualTo(12)
+  }
+
+  private fun lastTextChangedEventData(): WritableMap {
+    val events =
+        eventDispatcher.getRecordedDispatchedEvents().filterIsInstance<ReactTextChangedEvent>()
+    assertThat(events).isNotEmpty
+    return checkNotNull(events.last().internal_getEventData())
+  }
+}