From eda083eba02b8a39bb40f6297569b58c0f7c32ec Mon Sep 17 00:00:00 2001
From: Julian Meinking <12785972+DrJume@users.noreply.github.com>
Date: Sat, 18 Jun 2022 18:56:38 +0200
Subject: [PATCH] fix(runtime-core): `in` operator returning `false` for
 built-in instance properties in `exposeProxy`

`exposeProxy` implements a fallback logic for accessing built-in instance properties but was missing the same logic for the `in` operator in the Proxy's `has()` handler.

fix #6137
---
 packages/runtime-core/__tests__/apiExpose.spec.ts | 2 ++
 packages/runtime-core/src/component.ts            | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/packages/runtime-core/__tests__/apiExpose.spec.ts b/packages/runtime-core/__tests__/apiExpose.spec.ts
index 1235096b016..c717964e407 100644
--- a/packages/runtime-core/__tests__/apiExpose.spec.ts
+++ b/packages/runtime-core/__tests__/apiExpose.spec.ts
@@ -216,7 +216,9 @@ describe('api: expose', () => {
     }
     const root = nodeOps.createElement('div')
     render(h(Parent), root)
+    expect('$el' in childRef.value).toBe(true)
     expect(childRef.value.$el.tag).toBe('div')
+    expect('$parent' in grandChildRef.value).toBe(true)
     expect(grandChildRef.value.$parent).toBe(childRef.value)
     expect(grandChildRef.value.$parent.$parent).toBe(grandChildRef.value.$root)
   })
diff --git a/packages/runtime-core/src/component.ts b/packages/runtime-core/src/component.ts
index eededdf34d0..eefc537f7ef 100644
--- a/packages/runtime-core/src/component.ts
+++ b/packages/runtime-core/src/component.ts
@@ -942,6 +942,15 @@ export function getExposeProxy(instance: ComponentInternalInstance) {
           } else if (key in publicPropertiesMap) {
             return publicPropertiesMap[key](instance)
           }
+        },
+        has(target, key: string) {
+          if (key in target) {
+            return true
+          } else if (key in publicPropertiesMap) {
+            return true
+          }
+
+          return false
         }
       }))
     )