From 490ce6bb304e054b0e189c740ed9d5583750a0c3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bart=C5=82omiej=20B=C5=82oniarz?=
 <bartlomiej.bloniarz@swmansion.com>
Date: Tue, 11 Jun 2024 12:21:51 +0200
Subject: [PATCH] Avoid starting animations for non-layout updates

---
 .../cpp/LayoutAnimations/LayoutAnimationsProxy.cpp | 14 ++++++++++++--
 .../cpp/LayoutAnimations/LayoutAnimationsProxy.h   |  3 +++
 .../cpp/LayoutAnimations/LayoutAnimationsUtils.h   |  4 ++++
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/packages/react-native-reanimated/Common/cpp/LayoutAnimations/LayoutAnimationsProxy.cpp b/packages/react-native-reanimated/Common/cpp/LayoutAnimations/LayoutAnimationsProxy.cpp
index d1e87b52fed..85e4262cd1d 100644
--- a/packages/react-native-reanimated/Common/cpp/LayoutAnimations/LayoutAnimationsProxy.cpp
+++ b/packages/react-native-reanimated/Common/cpp/LayoutAnimations/LayoutAnimationsProxy.cpp
@@ -314,7 +314,8 @@ void LayoutAnimationsProxy::handleUpdatesAndEnterings(
       }
 
       case ShadowViewMutation::Type::Update: {
-        if (!layoutAnimationsManager_->hasLayoutAnimation(tag, LAYOUT)) {
+        auto shouldAnimate = hasLayoutChanged(mutation);
+        if (!layoutAnimationsManager_->hasLayoutAnimation(tag, LAYOUT) || (!shouldAnimate && !layoutAnimations_.contains(tag))) {
           // We should cancel any ongoing animation here to ensure that the
           // proper final state is reached for this view However, due to how
           // RNSScreens handle adding headers (a second commit is triggered to
@@ -324,6 +325,9 @@ void LayoutAnimationsProxy::handleUpdatesAndEnterings(
           // TODO: find a better solution for this problem
           filteredMutations.push_back(mutation);
           continue;
+        } else if (!shouldAnimate){
+          updateOngoingAnimationTarget(tag, mutation);
+          continue;
         }
         startLayoutAnimation(tag, mutation);
         break;
@@ -644,7 +648,7 @@ void LayoutAnimationsProxy::startLayoutAnimation(
   auto parentView = std::make_shared<ShadowView>(mutation.parentShadowView);
   layoutAnimations_.insert_or_assign(
       tag, LayoutAnimation{finalView, currentView, parentView, {}, count});
-
+      
   Snapshot currentValues(oldView, surfaceManager.getWindow(surfaceId));
   Snapshot targetValues(
       mutation.newChildShadowView, surfaceManager.getWindow(surfaceId));
@@ -671,6 +675,12 @@ void LayoutAnimationsProxy::startLayoutAnimation(
   });
 }
 
+void LayoutAnimationsProxy::updateOngoingAnimationTarget(
+  const int tag,
+  const ShadowViewMutation &mutation) const {
+  layoutAnimations_[tag].finalView = std::make_shared<ShadowView>(mutation.newChildShadowView);
+}
+
 void LayoutAnimationsProxy::maybeCancelAnimation(const int tag) const {
   if (!layoutAnimations_.contains(tag)) {
     return;
diff --git a/packages/react-native-reanimated/Common/cpp/LayoutAnimations/LayoutAnimationsProxy.h b/packages/react-native-reanimated/Common/cpp/LayoutAnimations/LayoutAnimationsProxy.h
index 9a65ea3cbbf..7ada07c2d73 100644
--- a/packages/react-native-reanimated/Common/cpp/LayoutAnimations/LayoutAnimationsProxy.h
+++ b/packages/react-native-reanimated/Common/cpp/LayoutAnimations/LayoutAnimationsProxy.h
@@ -82,6 +82,9 @@ struct LayoutAnimationsProxy : public MountingOverrideDelegate {
   void addOngoingAnimations(
       SurfaceId surfaceId,
       ShadowViewMutationList &mutations) const;
+  void updateOngoingAnimationTarget(
+      const int tag,
+      const ShadowViewMutation& mutation) const;
 
   void updateIndexForMutation(ShadowViewMutation &mutation) const;
 
diff --git a/packages/react-native-reanimated/Common/cpp/LayoutAnimations/LayoutAnimationsUtils.h b/packages/react-native-reanimated/Common/cpp/LayoutAnimations/LayoutAnimationsUtils.h
index b632af1dece..03a11477340 100644
--- a/packages/react-native-reanimated/Common/cpp/LayoutAnimations/LayoutAnimationsUtils.h
+++ b/packages/react-native-reanimated/Common/cpp/LayoutAnimations/LayoutAnimationsUtils.h
@@ -145,6 +145,10 @@ static inline bool isRNSScreen(std::shared_ptr<MutationNode> node) {
           node->mutation.oldChildShadowView.componentName, "RNSScreen");
 }
 
+static inline bool hasLayoutChanged(const ShadowViewMutation& mutation){
+  return mutation.oldChildShadowView.layoutMetrics.frame != mutation.newChildShadowView.layoutMetrics.frame;
+}
+
 static inline void mergeAndSwap(std::vector<std::shared_ptr<MutationNode>>& A, std::vector<std::shared_ptr<MutationNode>>& B){
   std::vector<std::shared_ptr<MutationNode>> merged;
   auto it1 = A.begin(), it2 = B.begin();