fix[devtools/updateFiberRecursively]: mount suspense fallback set in timed-out case

Author: hoxyq

packages/react-devtools-shared/src/backend/renderer.js

@@ -2345,6 +2345,18 @@ export function attach(
       const prevFallbackChildSet = prevFiberChild
         ? prevFiberChild.sibling
         : null;
+
+      if (prevFallbackChildSet == null && nextFallbackChildSet != null) {
+        mountFiberRecursively(
+          nextFallbackChildSet,
+          shouldIncludeInTree ? nextFiber : parentFiber,
+          true,
+          traceNearestHostComponentUpdate,
+        );
+
+        shouldResetChildren = true;
+      }
+
       if (
         nextFallbackChildSet != null &&
         prevFallbackChildSet != null &&

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

@@ -320,7 +320,7 @@ export function installHook(target: any): DevToolsHook | null {
 
   let uidCounter = 0;
 
-  function inject(renderer: ReactRenderer) {
+  function inject(renderer: ReactRenderer): number {
     const id = ++uidCounter;
     renderers.set(id, renderer);
 

packages/react-reconciler/src/ReactFiberDevToolsHook.js

@@ -52,10 +52,11 @@ export const isDevToolsPresent =
   typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ !== 'undefined';
 
 export function injectInternals(internals: Object): boolean {
-  if (typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ === 'undefined') {
+  if (!isDevToolsPresent) {
     // No DevTools
     return false;
   }
+
   const hook = __REACT_DEVTOOLS_GLOBAL_HOOK__;
   if (hook.isDisabled) {
     // This isn't a real property on the hook, but it can be set to opt out