fix(runtime-core): prioritize using the provides from currentApp in nested createApp (#11502)

close #11488

packages/runtime-core/__tests__/apiCreateApp.spec.ts

@@ -116,12 +116,25 @@ describe('api: createApp', () => {
     const app = createApp({
       setup() {
         provide('foo', 'should not be seen')
+
+        // nested createApp
+        const childApp = createApp({
+          setup() {
+            provide('foo', 'foo from child')
+          },
+        })
+
+        childApp.provide('foo', 2)
+        expect(childApp.runWithContext(() => inject('foo'))).toBe(2)
+
         return () => h('div')
       },
     })
     app.provide('foo', 1)
 
     expect(app.runWithContext(() => inject('foo'))).toBe(1)
+    const root = nodeOps.createElement('div')
+    app.mount(root)
 
     expect(
       app.runWithContext(() => {

packages/runtime-core/src/apiInject.ts

@@ -56,11 +56,14 @@ export function inject(
     // #2400
     // to support `app.use` plugins,
     // fallback to appContext's `provides` if the instance is at root
-    const provides = instance
-      ? instance.parent == null
-        ? instance.vnode.appContext && instance.vnode.appContext.provides
-        : instance.parent.provides
-      : currentApp!._context.provides
+    // #11488, in a nested createApp, prioritize using the provides from currentApp
+    const provides = currentApp
+      ? currentApp._context.provides
+      : instance
+        ? instance.parent == null
+          ? instance.vnode.appContext && instance.vnode.appContext.provides
+          : instance.parent.provides
+        : undefined
 
     if (provides && (key as string | symbol) in provides) {
       // TS doesn't allow symbol as index type