Simplify list of pending work

Some of this was added with "soft expiration" in mind, but now with our revised
model for how soft expiration will work, this isn't necessary.

It would be nice to remove more of this, but I think the list itself is inherent
because we need a way to track the start times, for <Timeout ms={ms} />.

Author: acdlite

packages/react-reconciler/src/ReactFiberPendingWork.js

@@ -27,7 +27,6 @@ export type PendingWork = {
   expirationTime: ExpirationTime,
   isSuspended: boolean,
   shouldTryResuming: boolean,
-  isRenderPhaseWork: boolean,
   next: PendingWork | null,
 };
 
@@ -50,7 +49,8 @@ export function addPendingWork(
   let insertBefore = root.firstPendingWork;
   while (insertBefore !== null) {
     if (insertBefore.expirationTime >= expirationTime) {
-      // Retry anything with an equal or lower expiration time
+      // Retry anything with an equal or lower expiration time, since it may
+      // be unblocked by the new work.
       insertBefore.shouldTryResuming = true;
     }
     if (insertBefore.expirationTime === expirationTime) {
@@ -74,45 +74,11 @@ export function addPendingWork(
       expirationTime,
       isSuspended: false,
       shouldTryResuming: false,
-      isRenderPhaseWork: false,
       next: null,
     };
     insertPendingWorkAtPosition(root, work, insertAfter, insertBefore);
   }
 }
-export function addRenderPhasePendingWork(
-  root: FiberRoot,
-  startTime: ExpirationTime,
-  expirationTime: ExpirationTime,
-): void {
-  // Render-phase updates are treated differently because, while they
-  // could potentially unblock earlier pending work, we assume that they won't.
-  // They are also coalesced differently (see findNextExpirationTimeToWorkOn).
-  let insertAfter = null;
-  let insertBefore = root.firstPendingWork;
-  while (insertBefore !== null) {
-    if (insertBefore.expirationTime === expirationTime) {
-      // Found a matching bucket
-      return;
-    }
-    if (insertBefore.expirationTime > expirationTime) {
-      // Found the insertion position
-      break;
-    }
-    insertAfter = insertBefore;
-    insertBefore = insertBefore.next;
-  }
-  // No matching level found. Create a new one.
-  const work: PendingWork = {
-    startTime,
-    expirationTime,
-    isSuspended: false,
-    shouldTryResuming: false,
-    isRenderPhaseWork: true,
-    next: null,
-  };
-  insertPendingWorkAtPosition(root, work, insertAfter, insertBefore);
-}
 
 export function flushPendingWork(
   root: FiberRoot,
@@ -135,14 +101,14 @@ export function flushPendingWork(
   if (firstUnflushedWork === null) {
     if (remainingExpirationTime !== NoWork) {
       // There was an update during the render phase that wasn't flushed.
-      addRenderPhasePendingWork(root, currentTime, remainingExpirationTime);
+      addPendingWork(root, currentTime, remainingExpirationTime);
     }
   } else if (
     remainingExpirationTime !== NoWork &&
     firstUnflushedWork.expirationTime > remainingExpirationTime
   ) {
     // There was an update during the render phase that wasn't flushed.
-    addRenderPhasePendingWork(root, currentTime, remainingExpirationTime);
+    addPendingWork(root, currentTime, remainingExpirationTime);
   }
 }
 
@@ -168,7 +134,8 @@ export function resumePendingWork(
   root: FiberRoot,
   expirationTime: ExpirationTime,
 ): void {
-  // Called when a promise resolves
+  // Called when a promise resolves. This "pings" React to retry the previously
+  // suspended render.
   let work = root.firstPendingWork;
   while (work !== null) {
     if (work.expirationTime === expirationTime) {
@@ -184,19 +151,12 @@ export function resumePendingWork(
 export function findNextExpirationTimeToWorkOn(
   root: FiberRoot,
 ): ExpirationTime {
-  // If there's a non-suspended interactive expiration time, return the first
-  // one. If everything is suspended, return the last retry time that's either
-  //   a) a render phase update
-  //   b) later or equal to the last suspended time
+  // Return the earliest time that either isn't suspended or has been pinged.
   let lastSuspendedTime = NoWork;
-  let lastRenderPhaseTime = NoWork;
   let lastRetryTime = NoWork;
   let work = root.firstPendingWork;
   while (work !== null) {
-    if (
-      !work.isSuspended &&
-      (!work.isRenderPhaseWork || lastSuspendedTime === NoWork)
-    ) {
+    if (!work.isSuspended) {
       return work.expirationTime;
     }
     if (
@@ -209,13 +169,6 @@ export function findNextExpirationTimeToWorkOn(
       if (lastRetryTime === NoWork || lastRetryTime < work.expirationTime) {
         lastRetryTime = work.expirationTime;
       }
-      if (
-        work.isRenderPhaseWork &&
-        (lastRenderPhaseTime === NoWork ||
-          lastRenderPhaseTime < work.expirationTime)
-      ) {
-        lastRenderPhaseTime = work.expirationTime;
-      }
     }
     work = work.next;
   }
@@ -228,7 +181,7 @@ export function findNextExpirationTimeToWorkOn(
   if (lastRetryTime >= lastSuspendedTime) {
     return lastRetryTime;
   }
-  return lastRenderPhaseTime;
+  return NoWork;
 }
 
 export function findStartTime(root: FiberRoot, expirationTime: ExpirationTime) {

packages/react-reconciler/src/ReactFiberScheduler.js

@@ -59,7 +59,6 @@ import ReactFiberInstrumentation from './ReactFiberInstrumentation';
 import ReactDebugCurrentFiber from './ReactDebugCurrentFiber';
 import {
   addPendingWork,
-  addRenderPhasePendingWork,
   flushPendingWork,
   findStartTime,
   findNextExpirationTimeToWorkOn,
@@ -1353,12 +1352,7 @@ export default function<T, P, I, TI, HI, PI, C, CC, CX, PL>(
             interruptedBy = fiber;
             resetStack();
           }
-          if (!isWorking || isCommitting) {
-            addPendingWork(root, startTime, expirationTime);
-          } else {
-            // We're in the render phase.
-            addRenderPhasePendingWork(root, startTime, expirationTime);
-          }
+          addPendingWork(root, startTime, expirationTime);
           if (
             // If we're in the render phase, we don't need to schedule this root
             // for an update, because we'll do it before we exit...