Clear existing text content before inserting children (facebook#8331)

Fixes a bug when updating from a single text child (or
dangerouslySetInnerHTML) to regular children, where the previous
text content never gets deleted.

Author: acdlite

scripts/fiber/tests-failing.txt

@@ -32,8 +32,6 @@ src/renderers/dom/shared/__tests__/ReactDOM-test.js
 * throws in render() if the update callback is not a function
 
 src/renderers/dom/shared/__tests__/ReactDOMComponent-test.js
-* should empty element when removing innerHTML
-* should transition from innerHTML to children in nested el
 * should warn for children on void elements
 * should report component containing invalid styles
 * should clean up input value tracking
@@ -104,7 +102,6 @@ src/renderers/shared/shared/__tests__/ReactEmptyComponent-test.js
 * throws when rendering null at the top level
 
 src/renderers/shared/shared/__tests__/ReactMultiChildText-test.js
-* should correctly handle all possible children for render and update
 * should reorder keyed text nodes
 
 src/renderers/shared/shared/__tests__/ReactStatelessComponent-test.js

scripts/fiber/tests-passing.txt

@@ -601,8 +601,10 @@ src/renderers/dom/shared/__tests__/ReactDOMComponent-test.js
 * should update arbitrary attributes for tags containing dashes
 * should clear all the styles when removing `style`
 * should update styles when `style` changes from null to object
+* should empty element when removing innerHTML
 * should transition from string content to innerHTML
 * should transition from innerHTML to string content
+* should transition from innerHTML to children in nested el
 * should transition from children to innerHTML in nested el
 * should not incur unnecessary DOM mutations for attributes
 * should not incur unnecessary DOM mutations for string properties
@@ -1397,6 +1399,7 @@ src/renderers/shared/shared/__tests__/ReactMultiChildReconcile-test.js
 * should insert non-empty children in middle where nulls were
 
 src/renderers/shared/shared/__tests__/ReactMultiChildText-test.js
+* should correctly handle all possible children for render and update
 * should throw if rendering both HTML and children
 * should render between nested components and inline children
 

src/renderers/dom/fiber/ReactDOMFiber.js

@@ -117,6 +117,22 @@ var DOMRenderer = ReactFiberReconciler({
     updateProperties(domElement, type, oldProps, newProps, root);
   },
 
+  shouldSetTextContent(props : Props) : boolean {
+    return (
+      typeof props.children === 'string' ||
+      typeof props.children === 'number' ||
+      (
+        typeof props.dangerouslySetInnerHTML === 'object' &&
+        props.dangerouslySetInnerHTML !== null &&
+        typeof props.dangerouslySetInnerHTML.__html === 'string'
+      )
+    );
+  },
+
+  resetTextContent(domElement : Instance) : void {
+    domElement.textContent = '';
+  },
+
   createTextInstance(text : string, internalInstanceHandle : Object) : TextInstance {
     var textNode : TextInstance = document.createTextNode(text);
     precacheFiberNode(internalInstanceHandle, textNode);

src/renderers/noop/ReactNoop.js

@@ -68,6 +68,15 @@ var NoopRenderer = ReactFiberReconciler({
     instance.prop = newProps.prop;
   },
 
+  shouldSetTextContent(props : Props) : boolean {
+    return (
+      typeof props.children === 'string' ||
+      typeof props.children === 'number'
+    );
+  },
+
+  resetTextContent(instance : Instance) : void {},
+
   createTextInstance(text : string) : TextInstance {
     var inst = { text : text, id: instanceCounter++ };
     // Hide from unit tests

src/renderers/shared/fiber/ReactFiberBeginWork.js

@@ -53,6 +53,7 @@ var {
 } = require('ReactPriorityLevel');
 var {
   Placement,
+  ContentReset,
 } = require('ReactTypeOfSideEffect');
 var ReactCurrentOwner = require('ReactCurrentOwner');
 var ReactFiberClassComponent = require('ReactFiberClassComponent');
@@ -210,14 +211,27 @@ module.exports = function<T, P, I, TI, C>(
   }
 
   function updateHostComponent(current, workInProgress) {
+    const nextProps = workInProgress.pendingProps;
+    const prevProps = current ? current.memoizedProps : null;
     let nextChildren = workInProgress.pendingProps.children;
-    if (typeof nextChildren === 'string' || typeof nextChildren === 'number') {
+    const isDirectTextChild = config.shouldSetTextContent(nextProps);
+    if (isDirectTextChild) {
       // We special case a direct text child of a host node. This is a common
       // case. We won't handle it as a reified child. We will instead handle
       // this in the host environment that also have access to this prop. That
       // avoids allocating another HostText fiber and traversing it.
       nextChildren = null;
+    } else if (prevProps && (
+      config.shouldSetTextContent(prevProps) ||
+      prevProps.children === null ||
+      typeof prevProps.children === 'undefined' ||
+      typeof prevProps.children === 'boolean'
+    )) {
+      // If we're switching from a direct text child to a normal child, or to
+      // empty, we need to schedule the text content to be reset.
+      workInProgress.effectTag |= ContentReset;
     }
+
     if (workInProgress.pendingProps.hidden &&
         workInProgress.pendingWorkPriority !== OffscreenPriority) {
       // If this host component is hidden, we can bail out on the children.

src/renderers/shared/fiber/ReactFiberCommitWork.js

@@ -30,6 +30,7 @@ var {
   Placement,
   Update,
   Callback,
+  ContentReset,
 } = require('ReactTypeOfSideEffect');
 
 module.exports = function<T, P, I, TI, C>(
@@ -38,6 +39,7 @@ module.exports = function<T, P, I, TI, C>(
 ) {
 
   const commitUpdate = config.commitUpdate;
+  const resetTextContent = config.resetTextContent;
   const commitTextUpdate = config.commitTextUpdate;
 
   const appendChild = config.appendChild;
@@ -83,6 +85,17 @@ module.exports = function<T, P, I, TI, C>(
     throw new Error('Expected to find a host parent.');
   }
 
+  function getHostParentFiber(fiber : Fiber) : Fiber {
+    let parent = fiber.return;
+    while (parent) {
+      if (isHostParent(parent)) {
+        return parent;
+      }
+      parent = parent.return;
+    }
+    throw new Error('Expected to find a host parent.');
+  }
+
   function isHostParent(fiber : Fiber) : boolean {
     return (
       fiber.tag === HostComponent ||
@@ -133,12 +146,29 @@ module.exports = function<T, P, I, TI, C>(
   }
 
   function commitPlacement(finishedWork : Fiber) : void {
-    // Clear effect from effect tag before any errors can be thrown, so that
-    // we don't attempt to do this again
-    finishedWork.effectTag &= ~Placement;
-
     // Recursively insert all host nodes into the parent.
-    const parent = getHostParent(finishedWork);
+    const parentFiber = getHostParentFiber(finishedWork);
+    let parent;
+    switch (parentFiber.tag) {
+      case HostComponent:
+        parent = parentFiber.stateNode;
+        break;
+      case HostContainer:
+        parent = parentFiber.stateNode.containerInfo;
+        break;
+      case Portal:
+        parent = parentFiber.stateNode.containerInfo;
+        break;
+      default:
+        throw new Error('Invalid host parent fiber.');
+    }
+    if (parentFiber.effectTag & ContentReset) {
+      // Reset the text content of the parent before doing any insertions
+      resetTextContent(parent);
+      // Clear ContentReset from the effect tag
+      parentFiber.effectTag &= ~ContentReset;
+    }
+
     const before = getHostSibling(finishedWork);
     // We only have the top Fiber that was inserted but we need recurse down its
     // children to find all the terminal nodes.

src/renderers/shared/fiber/ReactFiberReconciler.js

@@ -49,6 +49,9 @@ export type HostConfig<T, P, I, TI, C> = {
   prepareUpdate(instance : I, oldProps : P, newProps : P) : boolean,
   commitUpdate(instance : I, oldProps : P, newProps : P, internalInstanceHandle : OpaqueNode) : void,
 
+  shouldSetTextContent(props : P) : boolean,
+  resetTextContent(instance : I) : void,
+
   createTextInstance(text : string, internalInstanceHandle : OpaqueNode) : TI,
   commitTextUpdate(textInstance : TI, oldText : string, newText : string) : void,
 

src/renderers/shared/fiber/ReactFiberScheduler.js

@@ -40,6 +40,7 @@ var {
   Update,
   PlacementAndUpdate,
   Deletion,
+  ContentReset,
   Callback,
   Err,
 } = require('ReactTypeOfSideEffect');
@@ -168,11 +169,15 @@ module.exports = function<T, P, I, TI, C>(config : HostConfig<T, P, I, TI, C>) {
     pass1: while (true) {
       try {
         while (effectfulFiber) {
+          if (effectfulFiber.effectTag & ContentReset) {
+            config.resetTextContent(effectfulFiber.stateNode);
+          }
+
           // The following switch statement is only concerned about placement,
           // updates, and deletions. To avoid needing to add a case for every
           // possible bitmap value, we remove the secondary effects from the
           // effect tag and switch on that value.
-          let primaryEffectTag = effectfulFiber.effectTag & ~(Callback | Err);
+          let primaryEffectTag = effectfulFiber.effectTag & ~(Callback | Err | ContentReset);
           switch (primaryEffectTag) {
             case Placement: {
               commitPlacement(effectfulFiber);

src/renderers/shared/fiber/ReactTypeOfSideEffect.js

@@ -12,14 +12,15 @@
 
 'use strict';
 
-export type TypeOfSideEffect = 0 | 1 | 2 | 3 | 4 | 8 | 16;
+export type TypeOfSideEffect = 0 | 1 | 2 | 3 | 4 | 8 | 16 | 32;
 
 module.exports = {
-  NoEffect: 0,                                // 0b00000
-  Placement: 1,                               // 0b00001
-  Update: 2,                                  // 0b00010
-  PlacementAndUpdate: 3,                      // 0b00011
-  Deletion: 4,                                // 0b00100
-  Callback: 8,                                // 0b01000
-  Err: 16,                                    // 0b10000
+  NoEffect: 0,                                // 0b000000
+  Placement: 1,                               // 0b000001
+  Update: 2,                                  // 0b000010
+  PlacementAndUpdate: 3,                      // 0b000011
+  Deletion: 4,                                // 0b000100
+  ContentReset: 8,                            // 0b001000
+  Callback: 16,                               // 0b010000
+  Err: 32,                                    // 0b100000
 };