Skips mount for initial empty component layout

Summary: Skips mount for initial empty component layout Reviewed By: astreet Differential Revision: D55377095 fbshipit-source-id: 03679e027ccdd0d9852bd91298eeb1b2861fc7f7
facebook · Mar 28, 2024 · d7c66c8 · d7c66c8
1 parent 972ba38
commit d7c66c8
Show file tree

Hide file tree

Showing 2 changed files with 17 additions and 0 deletions.
diff --git a/litho-core/src/main/java/com/facebook/litho/ComponentTree.java b/litho-core/src/main/java/com/facebook/litho/ComponentTree.java
@@ -853,10 +853,19 @@ private void promoteCommittedLayoutStateToUI() {
     if (mCommittedLayoutState == null) {
       throw new RuntimeException("Cannot promote null LayoutState!");
     }
+
     if (mCommittedLayoutState == mMainThreadLayoutState) {
       return;
     }
+
+    final @Nullable LayoutState previousMainThreadLayoutState = mMainThreadLayoutState;
     mMainThreadLayoutState = mCommittedLayoutState;
+
+    if (LayoutState.isNullOrEmpty(previousMainThreadLayoutState)
+        && LayoutState.isNullOrEmpty(mCommittedLayoutState)) {
+      return;
+    }
+
     dispatchOnAttached();
 
     if (mLithoView != null) {

diff --git a/litho-core/src/main/java/com/facebook/litho/LayoutState.java b/litho-core/src/main/java/com/facebook/litho/LayoutState.java
@@ -242,6 +242,10 @@ boolean hasComponentsExcludedFromIncrementalMount() {
     return mHasComponentsExcludedFromIncrementalMount;
   }
 
+  public boolean isEmpty() {
+    return mResolveResult.component instanceof EmptyComponent;
+  }
+
   public RenderTree toRenderTree() {
     if (mCachedRenderTree != null) {
       return mCachedRenderTree;
@@ -737,4 +741,8 @@ public VisibilityBoundsTransformer getVisibilityBoundsTransformer() {
   public Map<Long, DynamicValueOutput> getDynamicValueOutputs() {
     return mDynamicValueOutputs;
   }
+
+  public static boolean isNullOrEmpty(@Nullable LayoutState layoutState) {
+    return layoutState == null || layoutState.isEmpty();
+  }
 }