Add Visibility flag for hiding/unhiding trees (#20043)

* Add Visibility flag for hiding/unhiding trees There's `beforeblur` logic in the snapshot phase that needs to visit every Suspense boundary whose visibility is toggled. Right now it does that by visiting Placement and Deletion effects. That includes many unrelated nodes. By adding a new flag specifically for toggling Visibility, we will only visit the relevant Suspense (and Offscreen) boundaries, instead of all nodes that have a Placement. Potential follow-ups (not urgent): - The `beforeblur` logic also has a check to see whether the visibility was toggled on or off. It only cares about things being hidden. As a follow up, I can split the Visibility flag into separate Hide/Show flags, and only visit Hide. - Now that this is separate from Update, we can move the rest of the Suspense's layout effects (like attaching retry listeners) to the passive phase. * Gate behind createEventHandle feature flag Only need to visit deleted and hidden trees during the snapshot phase if the experimental `createEventHandle` flag is enabled. Currently, it's only used internally at Facebook, not open source.

Author: acdlite

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

@@ -73,6 +73,7 @@ import {
 NoFlags,
 DidCapture,
 Snapshot,
+Visibility,
 MutationMask,
 LayoutMask,
 PassiveMask,
@@ -1154,8 +1155,8 @@ function completeWork(
 // TODO: Only schedule updates if not prevDidTimeout.
 if(nextDidTimeout){
 // If this boundary just timed out, schedule an effect to attach a
-// retry listener to the promise. This flag is also used to hide the
-// primary children.
+// retry listener to the promise.
+// TODO: Move to passive phase
 workInProgress.flags|=Update;
 }
 }
@@ -1167,7 +1168,7 @@ function completeWork(
 // primary children. In mutation mode, we also need the flag to
 // *unhide* children that were previously hidden, so check if this
 // is currently timed out, too.
-workInProgress.flags|=Update;
+workInProgress.flags|=Update|Visibility;
 }
 }
 if(
@@ -1176,6 +1177,7 @@ function completeWork(
 workInProgress.memoizedProps.suspenseCallback!=null
 ){
 // Always notify the callback
+// TODO: Move to passive phase
 workInProgress.flags|=Update;
 }
 bubbleProperties(workInProgress);
@@ -1523,7 +1525,7 @@ function completeWork(
 prevIsHidden!==nextIsHidden&&
 newProps.mode!=='unstable-defer-without-hiding'
 ){
-workInProgress.flags|=Update;
+workInProgress.flags|=Update|Visibility;
 }
 }
 

packages/react-reconciler/src/ReactFiberFlags.js

@@ -7,62 +7,72 @@
  * @flow
  */
 
+import{enableCreateEventHandleAPI}from'shared/ReactFeatureFlags';
+
 exporttypeFlags=number;
 
 // Don't change these two values. They're used by React Dev Tools.
-exportconstNoFlags=/* */0b000000000000000000;
-exportconstPerformedWork=/* */0b000000000000000001;
+exportconstNoFlags=/* */0b0000000000000000000;
+exportconstPerformedWork=/* */0b0000000000000000001;
 
 // You can change the rest (and add more).
-exportconstPlacement=/* */0b000000000000000010;
-exportconstUpdate=/* */0b000000000000000100;
-exportconstPlacementAndUpdate=/* */0b000000000000000110;
-exportconstDeletion=/* */0b000000000000001000;
-exportconstContentReset=/* */0b000000000000010000;
-exportconstCallback=/* */0b000000000000100000;
-exportconstDidCapture=/* */0b000000000001000000;
-exportconstRef=/* */0b000000000010000000;
-exportconstSnapshot=/* */0b000000000100000000;
-exportconstPassive=/* */0b000000001000000000;
-// TODO (effects) Remove this bit once the new reconciler is synced to the old.
-exportconstPassiveUnmountPendingDev=/* */0b000010000000000000;
-exportconstHydrating=/* */0b000000010000000000;
-exportconstHydratingAndUpdate=/* */0b000000010000000100;
+exportconstPlacement=/* */0b0000000000000000010;
+exportconstUpdate=/* */0b0000000000000000100;
+exportconstPlacementAndUpdate=/* */0b0000000000000000110;
+exportconstDeletion=/* */0b0000000000000001000;
+exportconstContentReset=/* */0b0000000000000010000;
+exportconstCallback=/* */0b0000000000000100000;
+exportconstDidCapture=/* */0b0000000000001000000;
+exportconstRef=/* */0b0000000000010000000;
+exportconstSnapshot=/* */0b0000000000100000000;
+exportconstPassive=/* */0b0000000001000000000;
+exportconstHydrating=/* */0b0000000010000000000;
+exportconstHydratingAndUpdate=/* */0b0000000010000000100;
+exportconstVisibility=/* */0b0000000100000000000;
 
 // Passive & Update & Callback & Ref & Snapshot
-exportconstLifecycleEffectMask=/* */0b000000001110100100;
+exportconstLifecycleEffectMask=/* */0b0000000001110100100;
 
 // Union of all host effects
-exportconstHostEffectMask=/* */0b000000011111111111;
+exportconstHostEffectMask=/* */0b0000000111111111111;
 
 // These are not really side effects, but we still reuse this field.
-exportconstIncomplete=/* */0b000000100000000000;
-exportconstShouldCapture=/* */0b000001000000000000;
-exportconstForceUpdateForLegacySuspense=/* */0b000100000000000000;
+exportconstIncomplete=/* */0b0000001000000000000;
+exportconstShouldCapture=/* */0b0000010000000000000;
+// TODO (effects) Remove this bit once the new reconciler is synced to the old.
+exportconstPassiveUnmountPendingDev=/* */0b0000100000000000000;
+exportconstForceUpdateForLegacySuspense=/* */0b0001000000000000000;
 
 // Static tags describe aspects of a fiber that are not specific to a render,
 // e.g. a fiber uses a passive effect (even if there are no updates on this particular render).
 // This enables us to defer more work in the unmount case,
 // since we can defer traversing the tree during layout to look for Passive effects,
 // and instead rely on the static flag as a signal that there may be cleanup work.
-exportconstPassiveStatic=/* */0b001000000000000000;
+exportconstPassiveStatic=/* */0b0010000000000000000;
 
 // Union of side effect groupings as pertains to subtreeFlags
-// TODO: Don't need to visit Placement during BeforeMutation phase
-// TODO: Only need to visit Deletions during BeforeMutation phase if an element
-// is focused.
-exportconstBeforeMutationMask=/* */0b000000000100001010;
-exportconstMutationMask=/* */0b000000010010011110;
-exportconstLayoutMask=/* */0b000000000010100100;
-exportconstPassiveMask=/* */0b000000001000001000;
+
+exportconstBeforeMutationMask=
+Snapshot|
+(enableCreateEventHandleAPI
+ ? // createEventHandle needs to visit deleted and hidden trees to
+// fire beforeblur
+// TODO: Only need to visit Deletions during BeforeMutation phase if an
+// element is focused.
+Deletion|Visibility
+ : 0);
+
+exportconstMutationMask=/* */0b0000000110010011110;
+exportconstLayoutMask=/* */0b0000000000010100100;
+exportconstPassiveMask=/* */0b0000000001000001000;
 
 // Union of tags that don't get reset on clones.
 // This allows certain concepts to persist without recalculting them,
 // e.g. whether a subtree contains passive effects or portals.
-exportconstStaticMask=/* */0b001000000000000000;
+exportconstStaticMask=/* */0b0010000000000000000;
 
 // These flags allow us to traverse to fibers that have effects on mount
 // without traversing the entire tree after every commit for
 // double invoking
-exportconstMountLayoutDev=/* */0b010000000000000000;
-exportconstMountPassiveDev=/* */0b100000000000000000;
+exportconstMountLayoutDev=/* */0b0100000000000000000;
+exportconstMountPassiveDev=/* */0b1000000000000000000;

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

@@ -134,6 +134,7 @@ import {
 HostEffectMask,
 Hydrating,
 HydratingAndUpdate,
+Visibility,
 BeforeMutationMask,
 MutationMask,
 LayoutMask,
@@ -2155,8 +2156,10 @@ function commitBeforeMutationEffectsImpl(fiber: Fiber) {
 
 if(!shouldFireAfterActiveInstanceBlur&&focusedInstanceHandle!==null){
 // Check to see if the focused element was inside of a hidden (Suspense) subtree.
-// TODO: Move this out of the hot path using a dedicated effect tag.
 if(
+// TODO: Can optimize this further with separate Hide and Show flags. We
+// only care about Hide here.
+(flags&Visibility)!==NoFlags&&
 fiber.tag===SuspenseComponent&&
 isSuspenseBoundaryBeingHidden(current,fiber)&&
 doesFiberContain(fiber,focusedInstanceHandle)