DevTools: fix initial host instance selection

packages/react-devtools-extensions/src/main/index.js

@@ -345,8 +345,6 @@ function mountReactDevTools() {
 
   createBridgeAndStore();
 
-  setReactSelectionFromBrowser(bridge);
-
   createComponentsPanel();
   createProfilerPanel();
 }

packages/react-devtools-shared/src/devtools/store.js

@@ -96,6 +96,7 @@ export default class Store extends EventEmitter<{
   componentFilters: [],
   error: [Error],
   hookSettings: [$ReadOnly<DevToolsHookSettings>],
+  hostInstanceSelected: [Element['id']],
   settingsUpdated: [$ReadOnly<DevToolsHookSettings>],
   mutated: [[Array<number>, Map<number, number>]],
   recordChangeDescriptions: [],
@@ -190,6 +191,9 @@ export default class Store extends EventEmitter<{
   _hookSettings: $ReadOnly<DevToolsHookSettings> | null = null;
   _shouldShowWarningsAndErrors: boolean = false;
 
+  // Only used in browser extension for synchronization with built-in Elements panel.
+  _lastSelectedHostInstanceElementId: Element['id'] | null = null;
+
   constructor(bridge: FrontendBridge, config?: Config) {
     super();
 
@@ -265,6 +269,7 @@ export default class Store extends EventEmitter<{
     bridge.addListener('saveToClipboard', this.onSaveToClipboard);
     bridge.addListener('hookSettings', this.onHookSettings);
     bridge.addListener('backendInitialized', this.onBackendInitialized);
+    bridge.addListener('selectElement', this.onHostInstanceSelected);
   }
 
   // This is only used in tests to avoid memory leaks.
@@ -481,6 +486,10 @@ export default class Store extends EventEmitter<{
     return this._unsupportedRendererVersionDetected;
   }
 
+  get lastSelectedHostInstanceElementId(): Element['id'] | null {
+    return this._lastSelectedHostInstanceElementId;
+  }
+
   containsElement(id: number): boolean {
     return this._idToElement.has(id);
   }
@@ -1431,6 +1440,7 @@ export default class Store extends EventEmitter<{
     bridge.removeListener('backendVersion', this.onBridgeBackendVersion);
     bridge.removeListener('bridgeProtocol', this.onBridgeProtocol);
     bridge.removeListener('saveToClipboard', this.onSaveToClipboard);
+    bridge.removeListener('selectElement', this.onHostInstanceSelected);
 
     if (this._onBridgeProtocolTimeoutID !== null) {
       clearTimeout(this._onBridgeProtocolTimeoutID);
@@ -1507,6 +1517,16 @@ export default class Store extends EventEmitter<{
     this._bridge.send('getHookSettings'); // Warm up cached hook settings
   };
 
+  onHostInstanceSelected: (elementId: number) => void = elementId => {
+    if (this._lastSelectedHostInstanceElementId === elementId) {
+      return;
+    }
+
+    this._lastSelectedHostInstanceElementId = elementId;
+    // By the time we emit this, there is no guarantee that TreeContext is rendered.
+    this.emit('hostInstanceSelected', elementId);
+  };
+
   getHookSettings: () => void = () => {
     if (this._hookSettings != null) {
       this.emit('hookSettings', this._hookSettings);

packages/react-devtools-shared/src/devtools/views/Components/TreeContext.js

@@ -39,7 +39,7 @@ import {
   startTransition,
 } from 'react';
 import {createRegExp} from '../utils';
-import {BridgeContext, StoreContext} from '../context';
+import {StoreContext} from '../context';
 import Store from '../../store';
 
 import type {Element} from 'react-devtools-shared/src/frontend/types';
@@ -836,7 +836,6 @@ function TreeContextController({
   defaultSelectedElementID,
   defaultSelectedElementIndex,
 }: Props): React.Node {
-  const bridge = useContext(BridgeContext);
   const store = useContext(StoreContext);
 
   const initialRevision = useMemo(() => store.revision, [store]);
@@ -899,9 +898,15 @@ function TreeContextController({
     numElements: store.numElements,
     ownerSubtreeLeafElementID: null,
     selectedElementID:
-      defaultSelectedElementID == null ? null : defaultSelectedElementID,
+      defaultSelectedElementID != null
+        ? defaultSelectedElementID
+        : store.lastSelectedHostInstanceElementId,
     selectedElementIndex:
-      defaultSelectedElementIndex == null ? null : defaultSelectedElementIndex,
+      defaultSelectedElementIndex != null
+        ? defaultSelectedElementIndex
+        : store.lastSelectedHostInstanceElementId
+          ? store.getIndexOfElementID(store.lastSelectedHostInstanceElementId)
+          : null,
 
     // Search
     searchIndex: null,
@@ -914,7 +919,9 @@ function TreeContextController({
 
     // Inspection element panel
     inspectedElementID:
-      defaultInspectedElementID == null ? null : defaultInspectedElementID,
+      defaultInspectedElementID != null
+        ? defaultInspectedElementID
+        : store.lastSelectedHostInstanceElementId,
   });
 
   const dispatchWrapper = useCallback(
@@ -929,11 +936,12 @@ function TreeContextController({
 
   // Listen for host element selections.
   useEffect(() => {
-    const handleSelectElement = (id: number) =>
+    const handler = (id: Element['id']) =>
       dispatchWrapper({type: 'SELECT_ELEMENT_BY_ID', payload: id});
-    bridge.addListener('selectElement', handleSelectElement);
-    return () => bridge.removeListener('selectElement', handleSelectElement);
-  }, [bridge, dispatchWrapper]);
+
+    store.addListener('hostInstanceSelected', handler);
+    return () => store.removeListener('hostInstanceSelected', handler);
+  }, [store, dispatchWrapper]);
 
   // If a newly-selected search result or inspection selection is inside of a collapsed subtree, auto expand it.
   // This needs to be a layout effect to avoid temporarily flashing an incorrect selection.