From e78bf723bff914dae5bb0da6280d5eb15c2ae293 Mon Sep 17 00:00:00 2001
From: Valentin Shergin <shergin@fb.com>
Date: Sun, 15 Jul 2018 16:46:17 -0700
Subject: [PATCH] Fabric: Removed last two plactical usages of
 `ShadowNode::sourceNode_`

Summary:
@public
 * In case of `ShadowTree` we just pass original old node as a `commit` method argument;
 * In case of `ConcreteViewShadowNode` we just don't need that because diffing algorithm does not use that information anymore.

Reviewed By: mdvacca

Differential Revision: D8753906

fbshipit-source-id: b8555083c7e72e9b3c0f9a8065745946d4cf44c7
---
 ReactCommon/fabric/uimanager/ShadowTree.cpp      |  6 +++---
 ReactCommon/fabric/uimanager/ShadowTree.h        |  2 +-
 ReactCommon/fabric/view/ConcreteViewShadowNode.h | 15 ---------------
 3 files changed, 4 insertions(+), 19 deletions(-)

diff --git a/ReactCommon/fabric/uimanager/ShadowTree.cpp b/ReactCommon/fabric/uimanager/ShadowTree.cpp
index 5dd54ecfa93..d179d9dcad1 100644
--- a/ReactCommon/fabric/uimanager/ShadowTree.cpp
+++ b/ReactCommon/fabric/uimanager/ShadowTree.cpp
@@ -78,7 +78,7 @@ void ShadowTree::complete(UnsharedRootShadowNode newRootShadowNode) {
     newRootShadowNode
   );
 
-  if (commit(newRootShadowNode)) {
+  if (commit(oldRootShadowNode, newRootShadowNode)) {
     emitLayoutEvents(instructions);
 
     if (delegate_) {
@@ -87,10 +87,10 @@ void ShadowTree::complete(UnsharedRootShadowNode newRootShadowNode) {
   }
 }
 
-bool ShadowTree::commit(const SharedRootShadowNode &newRootShadowNode) {
+bool ShadowTree::commit(const SharedRootShadowNode &oldRootShadowNode, const SharedRootShadowNode &newRootShadowNode) {
   std::lock_guard<std::mutex> lock(commitMutex_);
 
-  if (newRootShadowNode->getSourceNode() != rootShadowNode_) {
+  if (oldRootShadowNode != rootShadowNode_) {
     return false;
   }
 
diff --git a/ReactCommon/fabric/uimanager/ShadowTree.h b/ReactCommon/fabric/uimanager/ShadowTree.h
index 3bb6af8b44d..26927fc8b63 100644
--- a/ReactCommon/fabric/uimanager/ShadowTree.h
+++ b/ReactCommon/fabric/uimanager/ShadowTree.h
@@ -77,7 +77,7 @@ private:
 
   UnsharedRootShadowNode cloneRootShadowNode(const LayoutConstraints &layoutConstraints, const LayoutContext &layoutContext) const;
   void complete(UnsharedRootShadowNode newRootShadowNode);
-  bool commit(const SharedRootShadowNode &newRootShadowNode);
+  bool commit(const SharedRootShadowNode &oldRootShadowNode, const SharedRootShadowNode &newRootShadowNode);
   void emitLayoutEvents(const TreeMutationInstructionList &instructions);
 
   const Tag rootTag_;
diff --git a/ReactCommon/fabric/view/ConcreteViewShadowNode.h b/ReactCommon/fabric/view/ConcreteViewShadowNode.h
index c65f9ea060d..38f0c966def 100644
--- a/ReactCommon/fabric/view/ConcreteViewShadowNode.h
+++ b/ReactCommon/fabric/view/ConcreteViewShadowNode.h
@@ -105,21 +105,6 @@ public:
     auto childShadowNode = std::dynamic_pointer_cast<const ShadowNode>(child);
     assert(childShadowNode);
     auto childShadowNodeClone = childShadowNode->clone();
-
-    // This is overloading of `SharedLayoutableShadowNode::cloneAndReplaceChild`,
-    // the method is used to clone some node as a preparation for future mutation
-    // caused by relayout.
-    // Because those changes are not requested by UIManager, they add a layer
-    // of node generation (between the committed stage and new proposed stage).
-    // That additional layer confuses the Diffing algorithm which uses
-    // `sourceNode` for referencing the previous (aka committed) stage
-    // of the tree to produce mutation instructions.
-    // In other words, if we don't compensate this change here,
-    // the Diffing algorithm will compare wrong trees
-    // ("new-but-not-laid-out-yet vs. new" instead of "committed vs. new").
-    auto nonConstChildShadowNodeClone = std::const_pointer_cast<ShadowNode>(childShadowNodeClone);
-    nonConstChildShadowNodeClone->shallowSourceNode();
-
     ShadowNode::replaceChild(childShadowNode, childShadowNodeClone);
     return std::dynamic_pointer_cast<const LayoutableShadowNode>(childShadowNodeClone);
   }