Attempted refactoring of childLanes to be from workInProgress to parent

 (rather than from children to workInProgress). This attempt isn't quite right though. Has some test failures that requires additional investigation.

Author: Brian Vaughn

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

@@ -299,7 +299,7 @@ export function createWorkInProgress(current: Fiber, pendingProps: any): Fiber {
   // Static effects are not specific to a render.
   workInProgress.flags = current.flags & StaticMask;
   workInProgress.subtreeFlags = current.subtreeFlags & StaticMask;
-  workInProgress.childLanes = current.childLanes;
+  workInProgress.childLanes = NoLanes;
   workInProgress.lanes = current.lanes;
 
   workInProgress.child = current.child;
@@ -388,7 +388,7 @@ export function resetWorkInProgress(workInProgress: Fiber, renderLanes: Lanes) {
     }
   } else {
     // Reset to the cloned values that createWorkInProgress would've.
-    workInProgress.childLanes = current.childLanes;
+    workInProgress.childLanes = NoLanes;
     workInProgress.lanes = current.lanes;
 
     workInProgress.child = current.child;

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

@@ -1883,7 +1883,7 @@ function updateSuspenseComponent(current, workInProgress, renderLanes) {
           prevOffscreenState === null
             ? mountSuspenseOffscreenState(renderLanes)
             : updateSuspenseOffscreenState(prevOffscreenState, renderLanes);
-        primaryChildFragment.childLanes = getRemainingWorkInPrimaryTree(
+        primaryChildFragment.childLanes = workInProgress.childLanes = getRemainingWorkInPrimaryTree(
           current,
           renderLanes,
         );
@@ -1920,7 +1920,8 @@ function updateSuspenseComponent(current, workInProgress, renderLanes) {
           prevOffscreenState === null
             ? mountSuspenseOffscreenState(renderLanes)
             : updateSuspenseOffscreenState(prevOffscreenState, renderLanes);
-        primaryChildFragment.childLanes = getRemainingWorkInPrimaryTree(
+        // TODO (effects) Document
+        primaryChildFragment.childLanes = workInProgress.childLanes = getRemainingWorkInPrimaryTree(
           current,
           renderLanes,
         );
@@ -1989,6 +1990,18 @@ function mountSuspenseFallbackChildren(
     primaryChildFragment.childLanes = NoLanes;
     primaryChildFragment.pendingProps = primaryChildProps;
 
+    // TODO (effects) This is tricky because by the time we are resetting the childLanes here
+    // they have already bubbled to the parent SuspenseComponent and its parent also
+    // (during the previous complete phase bubbling back up to Suspense).
+    //
+    // Compare this to the old fork, where we will restart work on the Suspense node
+    // before bubbling higher (and letting the values leak out).
+    //
+    // We could reset childLanes for the parent SuspenseComponent safely,
+    // but we can't reset childLanes for its parent without potentially erasing sibling updates.
+    // Instead we need to prevent the childLanes from bubbling in the first place during a suspend.
+    workInProgress.childLanes = NoLanes;
+
     if (enableProfilerTimer && workInProgress.mode & ProfileMode) {
       // Reset the durations from the first pass so they aren't included in the
       // final amounts. This seems counterintuitive, since we're intentionally
@@ -2110,6 +2123,9 @@ function updateSuspenseFallbackChildren(
     primaryChildFragment.childLanes = NoLanes;
     primaryChildFragment.pendingProps = primaryChildProps;
 
+    // TODO (effects)
+    workInProgress.childLanes = NoLanes;
+
     if (enableProfilerTimer && workInProgress.mode & ProfileMode) {
       // Reset the durations from the first pass so they aren't included in the
       // final amounts. This seems counterintuitive, since we're intentionally
@@ -2969,7 +2985,7 @@ function bailoutOnAlreadyFinishedWork(
   markSkippedUpdateLanes(workInProgress.lanes);
 
   // Check if the children have any pending work.
-  if (!includesSomeLane(renderLanes, workInProgress.childLanes)) {
+  if (!includesSomeLane(renderLanes, current.childLanes)) {
     // The children don't have any work either. We can skip them.
     // TODO: Once we add back resuming, we should check if the children are
     // a work-in-progress set. If so, we need to transfer their effects.
@@ -3118,7 +3134,7 @@ function beginWork(
             // Profiler should only call onRender when one of its descendants actually rendered.
             const hasChildWork = includesSomeLane(
               renderLanes,
-              workInProgress.childLanes,
+              current.childLanes,
             );
             if (hasChildWork) {
               workInProgress.flags |= Update;
@@ -3197,9 +3213,15 @@ function beginWork(
         case SuspenseListComponent: {
           const didSuspendBefore = (current.flags & DidCapture) !== NoFlags;
 
+// TODO current.childLanes is right; workInProgress.childLanes is wrong.
+// Presumably we bubbled something up that we shouldn't have then.
+// Maybet his is a variation of the Suspense thing earlier?
+// Either we need to reset (or not copy)?
+// Or maybe we need to *set* or update in this case?
           const hasChildWork = includesSomeLane(
             renderLanes,
-            workInProgress.childLanes,
+            // workInProgress.childLanes,
+            current.childLanes, // This causes a loop for some tests
           );
 
           if (didSuspendBefore) {

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

@@ -684,7 +684,7 @@ function cutOffTailIfNeeded(
 
 function bubbleProperties(completedWork: Fiber): void {
   bubbleProfilerDurationsFromChildren(completedWork);
-  bubbleLanesFromChildren(completedWork);
+  bubbleLanesToParent(completedWork);
   bubbleFlagsToParent(completedWork);
 }
 
@@ -707,20 +707,18 @@ function bubbleFlagsToParent(completedWork: Fiber): void {
   }
 }
 
+// TODO (effects) Broken Suspense problem;
+// We aren't calling bubbleLanesToParent() for the Suspended components which means OffscreenLane doesn't bubble up.
+
 // TODO (effects) Temorary method; merge this into bubbleProperties once refactor is done.
-function bubbleLanesFromChildren(completedWork: Fiber): void {
-  let newChildLanes = NoLanes;
-  let child = completedWork.child;
-  while (child !== null) {
-    newChildLanes = mergeLanes(
-      newChildLanes,
-      mergeLanes(child.lanes, child.childLanes),
+function bubbleLanesToParent(completedWork: Fiber): void {
+  const parent = completedWork.return;
+  if (parent !== null) {
+    parent.childLanes = mergeLanes(
+      parent.childLanes,
+      mergeLanes(completedWork.lanes, completedWork.childLanes),
     );
-
-    child = child.sibling;
   }
-
-  completedWork.childLanes = newChildLanes;
 }
 
 // TODO (effects) Temorary method; merge this into bubbleProperties once refactor is done.
@@ -1014,6 +1012,8 @@ function completeWork(
         ) {
           transferActualDuration(workInProgress);
         }
+        // TODO (effects) Comment about why
+        // bubbleProperties(workInProgress);
         return workInProgress;
       }
 
@@ -1204,6 +1204,7 @@ function completeWork(
                     ForceSuspenseFallback,
                   ),
                 );
+                bubbleProperties(workInProgress);
                 return workInProgress.child;
               }
               row = row.sibling;
@@ -1332,6 +1333,7 @@ function completeWork(
           suspenseContext = setDefaultShallowSuspenseContext(suspenseContext);
         }
         pushSuspenseContext(workInProgress, suspenseContext);
+        bubbleProperties(next);
         // Do a pass over the next row.
         return next;
       }
@@ -1439,13 +1441,13 @@ function completeWork(
       }
 
       // Don't bubble properties for hidden children.
-      if (
-        !nextIsHidden ||
-        includesSomeLane(subtreeRenderLanes, (OffscreenLane: Lane)) ||
-        (workInProgress.mode & ConcurrentMode) === NoLanes
-      ) {
-        bubbleProperties(workInProgress);
-      }
+      // if (
+      //   !nextIsHidden ||
+      //   includesSomeLane(subtreeRenderLanes, (OffscreenLane: Lane)) ||
+      //   (workInProgress.mode & ConcurrentMode) === NoLanes
+      // ) {
+      bubbleProperties(workInProgress);
+      // }
 
       return null;
     }

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

@@ -150,6 +150,7 @@ import {
   SyncLane,
   SyncBatchedLane,
   NoTimestamp,
+  OffscreenLane,
   findUpdateLane,
   findTransitionLane,
   findRetryLane,