@samitouri / QOS-React / commits / e5dd82a79d

Warn for using a React owned node as a Container if it also has text content (#32774)

The problem with setting both `children` or `dangerouslySetInnerHTML` and also using a ref on a DOM node to either manually append children or using it as a Container for `createRoot` or `createPortal` is that it's ambiguous which children should win. Ideally you use one of the four options to control children. Meaning that ideally you always use a leaf container for refs like this. Unfortunately it's very common to use a React owned thing with children as a Container of a Portal. For example `document.body` can have both regular React children and be used as a Portal container. This isn't really fully supported and has some undefined behavior like relative order isn't guaranteed but still very common. It is extra bad if the children are a `string`/`number` or if `dangerouslySetInnerHTML` is set. Because then when ever that reactively updates it'll clear out any manually added DOM nodes. When this happens isn't guaranteed. It's always happening as far as the reactivity is concerned. See https://github.com/facebook/react/issues/31600 Therefore, we should warn for this specific pattern. This still allows non-text children as a compromise even though that behavior is also somewhat undefined.

Sebastian Markbåge committed Apr 1, 2025 at 12:11 UTC e5dd82a79dd41c9df8d903ca7ab7b3a977bc3371
2 files changed +48 -1
packages/react-dom-bindings/src/client/ReactDOMComponentTree.js
+1 -1
@@ -211,7 +211,7 @@ export function getNodeFromInstance(inst: Fiber): Instance | TextInstance {
211 }
212
213 export function getFiberCurrentPropsFromNode(
214 - node: Instance | TextInstance | SuspenseInstance,
214 + node: Container | Instance | TextInstance | SuspenseInstance,
215 ): Props {
216 return (node: any)[internalPropsKey] || null;
217 }
packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js
+47
@@ -30,6 +30,7 @@ import type {TransitionTypes} from 'react/src/ReactTransitionType';
30 import {NotPending} from '../shared/ReactDOMFormActions';
31
32 import {getCurrentRootHostContainer} from 'react-reconciler/src/ReactFiberHostContext';
33 +import {runWithFiberInDEV} from 'react-reconciler/src/ReactCurrentFiber';
34
35 import hasOwnProperty from 'shared/hasOwnProperty';
36 import {checkAttributeStringCoercion} from 'shared/CheckStringCoercion';
@@ -43,6 +44,8 @@ export {
44 import {
45 precacheFiberNode,
46 updateFiberProps,
47 + getFiberCurrentPropsFromNode,
48 + getInstanceFromNode,
49 getClosestInstanceFromNode,
50 getFiberFromScopeInstance,
51 getInstanceFromNode as getInstanceFromNodeDOMTree,
@@ -821,10 +824,51 @@ export function appendChild(
824 }
825 }
826
827 +function warnForReactChildrenConflict(container: Container): void {
828 + if (__DEV__) {
829 + if ((container: any).__reactWarnedAboutChildrenConflict) {
830 + return;
831 + }
832 + const props = getFiberCurrentPropsFromNode(container);
833 + if (props !== null) {
834 + const fiber = getInstanceFromNode(container);
835 + if (fiber !== null) {
836 + if (
837 + typeof props.children === 'string' ||
838 + typeof props.children === 'number'
839 + ) {
840 + (container: any).__reactWarnedAboutChildrenConflict = true;
841 + // Run the warning with the Fiber of the container for context of where the children are specified.
842 + // We could also maybe use the Portal. The current execution context is the child being added.
843 + runWithFiberInDEV(fiber, () => {
844 + console.error(
845 + 'Cannot use a ref on a React element as a container to `createRoot` or `createPortal` ' +
846 + 'if that element also sets "children" text content using React. It should be a leaf with no children. ' +
847 + "Otherwise it's ambiguous which children should be used.",
848 + );
849 + });
850 + } else if (props.dangerouslySetInnerHTML != null) {
851 + (container: any).__reactWarnedAboutChildrenConflict = true;
852 + runWithFiberInDEV(fiber, () => {
853 + console.error(
854 + 'Cannot use a ref on a React element as a container to `createRoot` or `createPortal` ' +
855 + 'if that element also sets "dangerouslySetInnerHTML" using React. It should be a leaf with no children. ' +
856 + "Otherwise it's ambiguous which children should be used.",
857 + );
858 + });
859 + }
860 + }
861 + }
862 + }
863 +}
864 +
865 export function appendChildToContainer(
866 container: Container,
867 child: Instance | TextInstance,
868 ): void {
869 + if (__DEV__) {
870 + warnForReactChildrenConflict(container);
871 + }
872 let parentNode: DocumentFragment | Element;
873 if (container.nodeType === DOCUMENT_NODE) {
874 parentNode = (container: any).body;
@@ -888,6 +932,9 @@ export function insertInContainerBefore(
932 child: Instance | TextInstance,
933 beforeChild: Instance | TextInstance | SuspenseInstance,
934 ): void {
935 + if (__DEV__) {
936 + warnForReactChildrenConflict(container);
937 + }
938 let parentNode: DocumentFragment | Element;
939 if (container.nodeType === DOCUMENT_NODE) {
940 parentNode = (container: any).body;