Add Profiler callback when nested udpates are scheduled

This callback accepts the no parameters (except for the current interactions). Users of this hook can inspect the call stack to access and log the source location of the component.

Author: Brian Vaughn

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

@@ -22,6 +22,7 @@ import {
   replayFailedUnitOfWorkWithInvokeGuardedCallback,
   enableProfilerTimer,
   enableProfilerNestedUpdatePhase,
+  enableProfilerNestedUpdateScheduledHook,
   enableSchedulerTracing,
   warnAboutUnmockedScheduler,
   deferRenderPhaseUpdateToNextBatch,
@@ -110,6 +111,7 @@ import {
   ForwardRef,
   MemoComponent,
   SimpleMemoComponent,
+  Profiler,
 } from './ReactWorkTags';
 import {LegacyRoot} from './ReactRootTags';
 import {
@@ -258,6 +260,10 @@ let workInProgress: Fiber | null = null;
 // The lanes we're rendering
 let workInProgressRootRenderLanes: Lanes = NoLanes;
 
+// Only used when enableProfilerNestedUpdateScheduledHook is true;
+// to track which root is currently committing layout effects.
+let rootCommittingMutationOrLayoutEffects: FiberRoot | null = null;
+
 // Stack that allows components to change the render lanes for its subtree
 // This is a superset of the lanes we started working on at the root. The only
 // case where it's different from `workInProgressRootRenderLanes` is when we
@@ -509,6 +515,30 @@ export function scheduleUpdateOnFiber(
   // Mark that the root has a pending update.
   markRootUpdated(root, lane, eventTime);
 
+  if (enableProfilerNestedUpdateScheduledHook) {
+    if (
+      executionContext === CommitContext &&
+      root === rootCommittingMutationOrLayoutEffects
+    ) {
+      if (fiber.mode & ProfileMode) {
+        let current = fiber;
+        while (current !== null) {
+          if (current.tag === Profiler) {
+            const {onNestedUpdateScheduled} = current.memoizedProps;
+            if (typeof onNestedUpdateScheduled === 'function') {
+              if (enableSchedulerTracing) {
+                onNestedUpdateScheduled(root.memoizedInteractions);
+              } else {
+                onNestedUpdateScheduled();
+              }
+            }
+          }
+          current = current.return;
+        }
+      }
+    }
+  }
+
   if (root === workInProgressRoot) {
     // Received an update to a tree that's in the middle of rendering. Mark
     // that there was an interleaved update work on this root. Unless the
@@ -1898,6 +1928,10 @@ function commitRootImpl(root, renderPriorityLevel) {
       recordCommitTime();
     }
 
+    if (enableProfilerNestedUpdateScheduledHook) {
+      rootCommittingMutationOrLayoutEffects = root;
+    }
+
     // The next phase is the mutation phase, where we mutate the host tree.
     commitMutationEffects(finishedWork, root, renderPriorityLevel);
 
@@ -1936,6 +1970,10 @@ function commitRootImpl(root, renderPriorityLevel) {
       markLayoutEffectsStopped();
     }
 
+    if (enableProfilerNestedUpdateScheduledHook) {
+      rootCommittingMutationOrLayoutEffects = null;
+    }
+
     // Tell Scheduler to yield at the end of the frame, so the browser has an
     // opportunity to paint.
     requestPaint();

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

@@ -23,6 +23,7 @@ import {
   enableProfilerTimer,
   enableProfilerCommitHooks,
   enableProfilerNestedUpdatePhase,
+  enableProfilerNestedUpdateScheduledHook,
   enableSchedulerTracing,
   warnAboutUnmockedScheduler,
   deferRenderPhaseUpdateToNextBatch,
@@ -112,6 +113,7 @@ import {
   OffscreenComponent,
   LegacyHiddenComponent,
   ScopeComponent,
+  Profiler,
 } from './ReactWorkTags';
 import {LegacyRoot} from './ReactRootTags';
 import {
@@ -329,6 +331,10 @@ let hasUncaughtError = false;
 let firstUncaughtError = null;
 let legacyErrorBoundariesThatAlreadyFailed: Set<mixed> | null = null;
 
+// Only used when enableProfilerNestedUpdateScheduledHook is true;
+// to track which root is currently committing layout effects.
+let rootCommittingMutationOrLayoutEffects: FiberRoot | null = null;
+
 let rootDoesHavePassiveEffects: boolean = false;
 let rootWithPendingPassiveEffects: FiberRoot | null = null;
 let pendingPassiveEffectsRenderPriority: ReactPriorityLevel = NoSchedulerPriority;
@@ -533,6 +539,30 @@ export function scheduleUpdateOnFiber(
   // Mark that the root has a pending update.
   markRootUpdated(root, lane, eventTime);
 
+  if (enableProfilerNestedUpdateScheduledHook) {
+    if (
+      executionContext === CommitContext &&
+      root === rootCommittingMutationOrLayoutEffects
+    ) {
+      if (fiber.mode & ProfileMode) {
+        let current = fiber;
+        while (current !== null) {
+          if (current.tag === Profiler) {
+            const {onNestedUpdateScheduled} = current.memoizedProps;
+            if (typeof onNestedUpdateScheduled === 'function') {
+              if (enableSchedulerTracing) {
+                onNestedUpdateScheduled(root.memoizedInteractions);
+              } else {
+                onNestedUpdateScheduled();
+              }
+            }
+          }
+          current = current.return;
+        }
+      }
+    }
+  }
+
   if (root === workInProgressRoot) {
     // Received an update to a tree that's in the middle of rendering. Mark
     // that there was an interleaved update work on this root. Unless the
@@ -2047,6 +2077,12 @@ function commitRootImpl(root, renderPriorityLevel) {
       recordCommitTime();
     }
 
+    if (enableProfilerNestedUpdateScheduledHook) {
+      // Track the root here, rather than in commitLayoutEffects(), because of ref setters.
+      // Updates scheduled during ref detachment should also be flagged.
+      rootCommittingMutationOrLayoutEffects = root;
+    }
+
     // The next phase is the mutation phase, where we mutate the host tree.
     nextEffect = firstEffect;
     do {
@@ -2112,6 +2148,10 @@ function commitRootImpl(root, renderPriorityLevel) {
 
     nextEffect = null;
 
+    if (enableProfilerNestedUpdateScheduledHook) {
+      rootCommittingMutationOrLayoutEffects = null;
+    }
+
     // Tell Scheduler to yield at the end of the frame, so the browser has an
     // opportunity to paint.
     requestPaint();