Eagerly set Deletions effect on Fiber when adding child to deletions …

…array

packages/react-reconciler/src/ReactChildFiber.new.js

@@ -293,6 +293,8 @@ function ChildReconciler(shouldTrackSideEffects) {
     } else {
       returnFiber.deletions.push(childToDelete);
     }
+    // TODO (effects) Rename this to better reflect its new usage (e.g. ChildDeletions)
+    returnFiber.effectTag |= Deletion;
     childToDelete.nextEffect = null;
     childToDelete.effectTag = Deletion;
   }

packages/react-reconciler/src/ReactFiberBeginWork.new.js

@@ -2071,6 +2071,8 @@ function updateSuspensePrimaryChildren(
     } else {
       workInProgress.deletions.push(currentFallbackChildFragment);
     }
+    // TODO (effects) Rename this to better reflect its new usage (e.g. ChildDeletions)
+    workInProgress.effectTag |= Deletion;
   }
 
   workInProgress.child = primaryChildFragment;
@@ -3052,6 +3054,8 @@ function remountFiber(
     } else {
       returnFiber.deletions.push(current);
     }
+    // TODO (effects) Rename this to better reflect its new usage (e.g. ChildDeletions)
+    returnFiber.effectTag |= Deletion;
     current.nextEffect = null;
     current.effectTag = Deletion;
 

packages/react-reconciler/src/ReactFiberHydrationContext.new.js

@@ -130,6 +130,8 @@ function deleteHydratableInstance(
   } else {
     returnFiber.deletions.push(childToDelete);
   }
+  // TODO (effects) Rename this to better reflect its new usage (e.g. ChildDeletions)
+  returnFiber.effectTag |= Deletion;
 
   // This might seem like it belongs on progressedFirstDeletion. However,
   // these children are not part of the reconciliation list of children.

packages/react-reconciler/src/ReactFiberWorkLoop.new.js

@@ -288,7 +288,6 @@ let globalMostRecentFallbackTime: number = 0;
 const FALLBACK_THROTTLE_MS: number = 500;
 const DEFAULT_TIMEOUT_MS: number = 5000;
 
-let nextEffect: Fiber | null = null;
 let hasUncaughtError = false;
 let firstUncaughtError = null;
 let legacyErrorBoundariesThatAlreadyFailed: Set<mixed> | null = null;
@@ -1805,10 +1804,8 @@ function resetChildLanes(completedWork: Fiber) {
       );
 
       subtreeTag |= child.subtreeTag;
+      // TODO (effects) Document why this exception is important
       subtreeTag |= child.effectTag & HostEffectMask;
-      if (child.deletions !== null) {
-        subtreeTag |= Deletion;
-      }
 
       if ((child.effectTag & Incomplete) !== NoEffect) {
         childrenDidNotComplete = true;
@@ -1850,10 +1847,8 @@ function resetChildLanes(completedWork: Fiber) {
       );
 
       subtreeTag |= child.subtreeTag;
+      // TODO (effects) Document why this exception is important
       subtreeTag |= child.effectTag & HostEffectMask;
-      if (child.deletions !== null) {
-        subtreeTag |= Deletion;
-      }
 
       if ((child.effectTag & Incomplete) !== NoEffect) {
         childrenDidNotComplete = true;
@@ -2013,8 +2008,6 @@ function commitRootImpl(root, renderPriorityLevel) {
     // layout, but class component lifecycles also fire here for legacy reasons.
     commitLayoutEffects(finishedWork, root, lanes);
 
-    nextEffect = null;
-
     // Tell Scheduler to yield at the end of the frame, so the browser has an
     // opportunity to paint.
     requestPaint();
@@ -2047,19 +2040,7 @@ function commitRootImpl(root, renderPriorityLevel) {
     pendingPassiveEffectsLanes = lanes;
     pendingPassiveEffectsRenderPriority = renderPriorityLevel;
   } else {
-    // We are done with the effect chain at this point so let's clear the
-    // nextEffect pointers to assist with GC. If we have passive effects, we'll
-    // clear this in flushPassiveEffects.
-    // TODO (effects) Traverse with subtreeTag Deletion and detatch deletions array only
-    nextEffect = firstEffect;
-    while (nextEffect !== null) {
-      const nextNextEffect = nextEffect.nextEffect;
-      nextEffect.nextEffect = null;
-      if (nextEffect.effectTag & Deletion) {
-        detachFiberAfterEffects(nextEffect);
-      }
-      nextEffect = nextNextEffect;
-    }
+    // TODO (effects) Detach sibling pointers for deleted Fibers
   }
 
   // Read this again, since an effect might have updated it
@@ -2658,20 +2639,7 @@ function flushPassiveEffectsImpl() {
     }
   }
 
-  // Note: This currently assumes there are no passive effects on the root fiber
-  // because the root is not part of its own effect list.
-  // This could change in the future.
-  // TODO (effects) Traverse with subtreeTag Deletion and detatch deletions array only
-  let effect = root.current.firstEffect;
-  while (effect !== null) {
-    const nextNextEffect = effect.nextEffect;
-    // Remove nextEffect pointer to assist GC
-    effect.nextEffect = null;
-    if (effect.effectTag & Deletion) {
-      detachFiberAfterEffects(effect);
-    }
-    effect = nextNextEffect;
-  }
+  // TODO (effects) Detach sibling pointers for deleted Fibers
 
   if (enableProfilerTimer && enableProfilerCommitHooks) {
     const profilerEffects = pendingPassiveProfilerEffects;
@@ -3762,7 +3730,3 @@ export function act(callback: () => Thenable<mixed>): Thenable<void> {
     };
   }
 }
-
-function detachFiberAfterEffects(fiber: Fiber): void {
-  fiber.sibling = null;
-}