Add featureflag to not re-order mount items in FabricMountingManager (f…

…acebook#46702)

Summary:
Pull Request resolved: facebook#46702

In facebook#44188, we've started combining multiple transactions in a single transaction, to meet React's atomicity requirements, while also dealing with the constraints of Android's Fabric implementation.

This revealed a bug where in some scenarios (especially when using transitions), a node may be deleted and created during the same transaction. The current implementation of FabricMountingManager assumes it can safely reorder some operations, which it does to optimize the size of IntBufferBatch mount items. This is however incorrect and unsafe when multiple transactions are merged.

**Example:**

Differentiator output:

```
# Transaction 1
Remove facebook#100 from facebook#11
Delete facebook#100

# Transaction 2
Create facebook#100
Insert facebook#100 into facebook#11
```
FabricMountingManager output
```
Remove facebook#100 from facebook#11
Insert facebook#100 into facebook#11
Delete facebook#100
```

Note that the create action is also skipped, because we only update `allocatedViewTags` after processing all mutations, leading FabricMountingManager to assume creation is not required.

This leads to an invalid state in SurfaceMountingManager, which will be surfaced as a crash in `getViewState` on the next mutation that interacts with these views.

Changelog: [Android][Fixed] Fix crash in getViewState when using suspense fallbacks.

Reviewed By: sammy-SC

Differential Revision: D63148523

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlags.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<f98a6ddd268fb59b5ee5edb4997b3a63>>
+ * @generated SignedSource<<575eeb1e291c1a372eba7aabcdd948e3>>
  */
 
 /**
@@ -52,6 +52,12 @@ public object ReactNativeFeatureFlags {
   @JvmStatic
   public fun disableEventLoopOnBridgeless(): Boolean = accessor.disableEventLoopOnBridgeless()
 
+  /**
+   * Prevent FabricMountingManager from reordering mountitems, which may lead to invalid state on the UI thread
+   */
+  @JvmStatic
+  public fun disableMountItemReorderingAndroid(): Boolean = accessor.disableMountItemReorderingAndroid()
+
   /**
    * Kill-switch to turn off support for aling-items:baseline on Fabric iOS.
    */

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsCxxAccessor.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<6b3d3512d88c836dd809204cad636211>>
+ * @generated SignedSource<<f93759a639dbbb95d3307003e4907c86>>
  */
 
 /**
@@ -24,6 +24,7 @@ public class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAccesso
   private var allowRecursiveCommitsWithSynchronousMountOnAndroidCache: Boolean? = null
   private var completeReactInstanceCreationOnBgThreadOnAndroidCache: Boolean? = null
   private var disableEventLoopOnBridgelessCache: Boolean? = null
+  private var disableMountItemReorderingAndroidCache: Boolean? = null
   private var enableAlignItemsBaselineOnFabricIOSCache: Boolean? = null
   private var enableAndroidLineHeightCenteringCache: Boolean? = null
   private var enableBridgelessArchitectureCache: Boolean? = null
@@ -104,6 +105,15 @@ public class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAccesso
     return cached
   }
 
+  override fun disableMountItemReorderingAndroid(): Boolean {
+    var cached = disableMountItemReorderingAndroidCache
+    if (cached == null) {
+      cached = ReactNativeFeatureFlagsCxxInterop.disableMountItemReorderingAndroid()
+      disableMountItemReorderingAndroidCache = cached
+    }
+    return cached
+  }
+
   override fun enableAlignItemsBaselineOnFabricIOS(): Boolean {
     var cached = enableAlignItemsBaselineOnFabricIOSCache
     if (cached == null) {

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsCxxInterop.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<0ef9a66ccabeb0357f4b15c3e897f8fb>>
+ * @generated SignedSource<<44d0fe9a36e5e51816e10b8799d451fe>>
  */
 
 /**
@@ -36,6 +36,8 @@ public object ReactNativeFeatureFlagsCxxInterop {
 
   @DoNotStrip @JvmStatic public external fun disableEventLoopOnBridgeless(): Boolean
 
+  @DoNotStrip @JvmStatic public external fun disableMountItemReorderingAndroid(): Boolean
+
   @DoNotStrip @JvmStatic public external fun enableAlignItemsBaselineOnFabricIOS(): Boolean
 
   @DoNotStrip @JvmStatic public external fun enableAndroidLineHeightCentering(): Boolean

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsDefaults.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<ee5400241a72652a2f8ff343a06e4e8c>>
+ * @generated SignedSource<<917a6effbfd0a476cc05d90abee3c80b>>
  */
 
 /**
@@ -31,6 +31,8 @@ public open class ReactNativeFeatureFlagsDefaults : ReactNativeFeatureFlagsProvi
 
   override fun disableEventLoopOnBridgeless(): Boolean = false
 
+  override fun disableMountItemReorderingAndroid(): Boolean = false
+
   override fun enableAlignItemsBaselineOnFabricIOS(): Boolean = true
 
   override fun enableAndroidLineHeightCentering(): Boolean = false

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsLocalAccessor.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<949f5cdf6d0a4015fbd680ba718dce6d>>
+ * @generated SignedSource<<2ad36465b1a411cb55d85416bd8ba823>>
  */
 
 /**
@@ -28,6 +28,7 @@ public class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcces
   private var allowRecursiveCommitsWithSynchronousMountOnAndroidCache: Boolean? = null
   private var completeReactInstanceCreationOnBgThreadOnAndroidCache: Boolean? = null
   private var disableEventLoopOnBridgelessCache: Boolean? = null
+  private var disableMountItemReorderingAndroidCache: Boolean? = null
   private var enableAlignItemsBaselineOnFabricIOSCache: Boolean? = null
   private var enableAndroidLineHeightCenteringCache: Boolean? = null
   private var enableBridgelessArchitectureCache: Boolean? = null
@@ -112,6 +113,16 @@ public class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcces
     return cached
   }
 
+  override fun disableMountItemReorderingAndroid(): Boolean {
+    var cached = disableMountItemReorderingAndroidCache
+    if (cached == null) {
+      cached = currentProvider.disableMountItemReorderingAndroid()
+      accessedFeatureFlags.add("disableMountItemReorderingAndroid")
+      disableMountItemReorderingAndroidCache = cached
+    }
+    return cached
+  }
+
   override fun enableAlignItemsBaselineOnFabricIOS(): Boolean {
     var cached = enableAlignItemsBaselineOnFabricIOSCache
     if (cached == null) {

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsProvider.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<4e42e76c98b7434273e4f11212f0527b>>
+ * @generated SignedSource<<9770a9f125b8bcb4b1daef9e3458433f>>
  */
 
 /**
@@ -31,6 +31,8 @@ public interface ReactNativeFeatureFlagsProvider {
 
   @DoNotStrip public fun disableEventLoopOnBridgeless(): Boolean
 
+  @DoNotStrip public fun disableMountItemReorderingAndroid(): Boolean
+
   @DoNotStrip public fun enableAlignItemsBaselineOnFabricIOS(): Boolean
 
   @DoNotStrip public fun enableAndroidLineHeightCentering(): Boolean