From c41126f56f4ac04d1b2e07d7f97b72258d8eb12c Mon Sep 17 00:00:00 2001
From: Andrew Clark <git@andrewclark.io>
Date: Thu, 8 Nov 2018 11:00:08 -0800
Subject: [PATCH] [Synchronous Suspense] Don't delete children of suspended
 component

Vestigial behavior that should have been removed in #13823.

Found using the Suspense fuzz tester in #14147.
---
 .../react-reconciler/src/ReactFiberUnwindWork.js    | 13 +------------
 .../ReactSuspenseWithNoopRenderer-test.internal.js  |  3 +++
 2 files changed, 4 insertions(+), 12 deletions(-)

diff --git a/packages/react-reconciler/src/ReactFiberUnwindWork.js b/packages/react-reconciler/src/ReactFiberUnwindWork.js
index 6fb2e080687e5..4ddd5db8a9d28 100644
--- a/packages/react-reconciler/src/ReactFiberUnwindWork.js
+++ b/packages/react-reconciler/src/ReactFiberUnwindWork.js
@@ -70,7 +70,6 @@ import {
   LOW_PRIORITY_EXPIRATION,
 } from './ReactFiberExpirationTime';
 import {findEarliestOutstandingPriorityLevel} from './ReactFiberPendingPriority';
-import {reconcileChildren} from './ReactFiberBeginWork';
 
 function createRootErrorUpdate(
   fiber: Fiber,
@@ -238,20 +237,10 @@ function throwException(
         if ((workInProgress.mode & ConcurrentMode) === NoEffect) {
           workInProgress.effectTag |= DidCapture;
 
-          // Unmount the source fiber's children
-          const nextChildren = null;
-          reconcileChildren(
-            sourceFiber.alternate,
-            sourceFiber,
-            nextChildren,
-            renderExpirationTime,
-          );
-          sourceFiber.effectTag &= ~Incomplete;
-
           // We're going to commit this fiber even though it didn't complete.
           // But we shouldn't call any lifecycle methods or callbacks. Remove
           // all lifecycle effect tags.
-          sourceFiber.effectTag &= ~LifecycleEffectMask;
+          sourceFiber.effectTag &= ~(LifecycleEffectMask | Incomplete);
 
           if (sourceFiber.tag === ClassComponent) {
             const current = sourceFiber.alternate;
diff --git a/packages/react-reconciler/src/__tests__/ReactSuspenseWithNoopRenderer-test.internal.js b/packages/react-reconciler/src/__tests__/ReactSuspenseWithNoopRenderer-test.internal.js
index de4b75337ef3f..9580c425a47b0 100644
--- a/packages/react-reconciler/src/__tests__/ReactSuspenseWithNoopRenderer-test.internal.js
+++ b/packages/react-reconciler/src/__tests__/ReactSuspenseWithNoopRenderer-test.internal.js
@@ -937,6 +937,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       ]);
       expect(ReactNoop.getChildrenAsJSX()).toEqual(
         <React.Fragment>
+          <span hidden={true} prop="Step: 1" />
           <span hidden={true} prop="Sibling" />
           <span prop="Loading (1)" />
           <span prop="Loading (2)" />
@@ -1060,6 +1061,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
         expect(ReactNoop.getChildrenAsJSX()).toEqual(
           <React.Fragment>
             <span hidden={true} prop="Before" />
+            <span hidden={true} prop="Async: 1" />
             <span hidden={true} prop="After" />
             <span prop="Loading..." />
 
@@ -1194,6 +1196,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
         expect(ReactNoop.getChildrenAsJSX()).toEqual(
           <React.Fragment>
             <span hidden={true} prop="Before" />
+            <span hidden={true} prop="Async: 1" />
             <span hidden={true} prop="After" />
             <span prop="Loading..." />