From 68ce28a0eea2ef9ffd4586333f6c6afd5ef821ed Mon Sep 17 00:00:00 2001
From: Nick Gerleman <ngerlem@meta.com>
Date: Mon, 8 May 2023 16:30:06 -0700
Subject: [PATCH] Fix YGNodeSetConfig causing excessive dirtying (#37316)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/37316

In Fabric, a ShadowNode may re-initialize YGConfig several times throughout the lifetime of a perpetually cloned Yoga Node.

RN sets `pointScaleFactor` lazily, when laying out the rootview. So right now it initializes a config to `pointScaleFactor` of 1.0, sets it, sets a new `pointScaleFactor` on the config, then repeats. This cycles the config between two `pointScaleFactor` values and will excessively dirty the node now that `YGNodeSetConfig` dirties on config change (D45505089)

This change makes it so that we retain previously used `pointScaleFactor` when cloning the Yoga nodes.

Changelog: [Internal]

Reviewed By: rozele

Differential Revision: D45669878

fbshipit-source-id: bfd2e185d9264a1cda64e59132960060385e16f1
---
 .../components/view/YogaLayoutableShadowNode.cpp  | 15 +++++++++++++--
 .../components/view/YogaLayoutableShadowNode.h    |  4 +++-
 .../react-native/ReactCommon/yoga/yoga/Yoga.cpp   |  4 ++++
 .../react-native/ReactCommon/yoga/yoga/Yoga.h     |  1 +
 4 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/packages/react-native/ReactCommon/react/renderer/components/view/YogaLayoutableShadowNode.cpp b/packages/react-native/ReactCommon/react/renderer/components/view/YogaLayoutableShadowNode.cpp
index 75e6c1b15ee..fb4e57deaff 100644
--- a/packages/react-native/ReactCommon/react/renderer/components/view/YogaLayoutableShadowNode.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/components/view/YogaLayoutableShadowNode.cpp
@@ -120,9 +120,13 @@ YogaLayoutableShadowNode::YogaLayoutableShadowNode(
     }
   }
 
+  YGConfigRef previousConfig = YGNodeGetConfig(
+      &static_cast<YogaLayoutableShadowNode const &>(sourceShadowNode)
+           .yogaNode_);
+
   yogaNode_.setContext(this);
   yogaNode_.setOwner(nullptr);
-  yogaNode_.setConfig(&initializeYogaConfig(yogaConfig_));
+  yogaNode_.setConfig(&initializeYogaConfig(yogaConfig_, previousConfig));
   updateYogaChildrenOwnersIfNeeded();
 
   // This is the only legit place where we can dirty cloned Yoga node.
@@ -742,10 +746,17 @@ YogaLayoutableShadowNode &YogaLayoutableShadowNode::shadowNodeFromContext(
       *static_cast<ShadowNode *>(yogaNode->getContext()));
 }
 
-YGConfig &YogaLayoutableShadowNode::initializeYogaConfig(YGConfig &config) {
+YGConfig &YogaLayoutableShadowNode::initializeYogaConfig(
+    YGConfig &config,
+    const YGConfigRef previousConfig) {
   YGConfigSetCloneNodeFunc(
       &config, YogaLayoutableShadowNode::yogaNodeCloneCallbackConnector);
   YGConfigSetErrata(&config, YGErrataAll);
+  if (previousConfig != nullptr) {
+    YGConfigSetPointScaleFactor(
+        &config, YGConfigGetPointScaleFactor(previousConfig));
+  }
+
 #ifdef RN_DEBUG_YOGA_LOGGER
   YGConfigSetPrintTreeFlag(&config, true);
 #endif
diff --git a/packages/react-native/ReactCommon/react/renderer/components/view/YogaLayoutableShadowNode.h b/packages/react-native/ReactCommon/react/renderer/components/view/YogaLayoutableShadowNode.h
index 9ad7f28cf03..9456b0ccc0b 100644
--- a/packages/react-native/ReactCommon/react/renderer/components/view/YogaLayoutableShadowNode.h
+++ b/packages/react-native/ReactCommon/react/renderer/components/view/YogaLayoutableShadowNode.h
@@ -132,7 +132,9 @@ class YogaLayoutableShadowNode : public LayoutableShadowNode {
    */
   void adoptYogaChild(size_t index);
 
-  static YGConfig &initializeYogaConfig(YGConfig &config);
+  static YGConfig &initializeYogaConfig(
+      YGConfig &config,
+      YGConfigRef previousConfig = nullptr);
   static YGNode *yogaNodeCloneCallbackConnector(
       YGNode *oldYogaNode,
       YGNode *parentYogaNode,
diff --git a/packages/react-native/ReactCommon/yoga/yoga/Yoga.cpp b/packages/react-native/ReactCommon/yoga/yoga/Yoga.cpp
index d9863a2f19d..8e2fdb4de56 100644
--- a/packages/react-native/ReactCommon/yoga/yoga/Yoga.cpp
+++ b/packages/react-native/ReactCommon/yoga/yoga/Yoga.cpp
@@ -4075,6 +4075,10 @@ YOGA_EXPORT void YGConfigSetPointScaleFactor(
   }
 }
 
+YOGA_EXPORT float YGConfigGetPointScaleFactor(const YGConfigRef config) {
+  return config->getPointScaleFactor();
+}
+
 static void YGRoundToPixelGrid(
     const YGNodeRef node,
     const double pointScaleFactor,
diff --git a/packages/react-native/ReactCommon/yoga/yoga/Yoga.h b/packages/react-native/ReactCommon/yoga/yoga/Yoga.h
index 1beb320e08a..de07aeac8b7 100644
--- a/packages/react-native/ReactCommon/yoga/yoga/Yoga.h
+++ b/packages/react-native/ReactCommon/yoga/yoga/Yoga.h
@@ -317,6 +317,7 @@ WIN_EXPORT void YGAssertWithConfig(
 WIN_EXPORT void YGConfigSetPointScaleFactor(
     YGConfigRef config,
     float pixelsInPoint);
+WIN_EXPORT float YGConfigGetPointScaleFactor(YGConfigRef config);
 
 // Yoga previously had an error where containers would take the maximum space
 // possible instead of the minimum like they are supposed to. In practice this