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Skip the duplicate state and event emitter for views created and inserted in one transaction #59707

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Skip the duplicate state and event emitter for views created and inserted in one transaction #59707

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b9470c3
Skip the duplicate state and event emitter for views created and inse…
tomekzaw Oct 30, 2026
100d58c
Merge branch 'main' into skip-duplicate-state-and-emitter
tomekzaw Nov 2, 2026
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38 changes: 30 additions & 8 deletions packages/react-native/ReactAndroid/src/main/jni/react/fabric/FabricMountingManager.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -618,6 +618,15 @@ void FabricMountingManager::executeMount(
std::vector<CppMountItem> cppUpdateOverflowInsetMountItems;
std::vector<CppMountItem> cppUpdateEventEmitterMountItems;

// Views created by this transaction, with the state and event emitter their
// Create item already passes to Java. Their Insert doesn't need to pass them
// again.
struct CreatedView {
const State* state;
const EventEmitter* eventEmitter;
};
std::unordered_map<Tag, CreatedView> createdViews;

{
std::lock_guard allocatedViewsLock(allocatedViewsMutex_);

Expand Down Expand Up @@ -657,6 +666,9 @@ void FabricMountingManager::executeMount(
if (shouldCreateView) {
cppCommonMountItems.push_back(
CppMountItem::CreateMountItem(newChildShadowView));
createdViews[newChildShadowView.tag] = CreatedView{
.state = newChildShadowView.state.get(),
.eventEmitter = newChildShadowView.eventEmitter.get()};
} else {
allocatedView->second.state = AllocatedViewState::Mounted;
}
Expand Down Expand Up @@ -756,6 +768,13 @@ void FabricMountingManager::executeMount(
break;
}
case ShadowViewMutation::Insert: {
auto createdView = createdViews.find(newChildShadowView.tag);
bool createdWithSameState = createdView != createdViews.end() &&
createdView->second.state == newChildShadowView.state.get();
bool createdWithSameEventEmitter =
createdView != createdViews.end() &&
createdView->second.eventEmitter ==
newChildShadowView.eventEmitter.get();
if (!isVirtual) {
// Insert item
cppCommonMountItems.push_back(
Expand Down Expand Up @@ -804,7 +823,7 @@ void FabricMountingManager::executeMount(
}

// State
if (newChildShadowView.state) {
if (newChildShadowView.state && !createdWithSameState) {
(maintainMutationOrder ? cppCommonMountItems
: cppUpdateStateMountItems)
.push_back(
Expand Down Expand Up @@ -845,13 +864,16 @@ void FabricMountingManager::executeMount(
}

// EventEmitter
// On insert we always update the event emitter, as we do not pass
// it in when preallocating views
(maintainMutationOrder ? cppCommonMountItems
: cppUpdateEventEmitterMountItems)
.push_back(
CppMountItem::UpdateEventEmitterMountItem(
mutation.newChildShadowView));
// On insert we update the event emitter, as we do not pass it in
// when preallocating views. A view created by this transaction
// already got it with its Create item.
if (!createdWithSameEventEmitter) {
(maintainMutationOrder ? cppCommonMountItems
: cppUpdateEventEmitterMountItems)
.push_back(
CppMountItem::UpdateEventEmitterMountItem(
mutation.newChildShadowView));
}

break;
}
Expand Down
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