From f0605a8e8a9f8616b88db2ffbe86f9acc2e94b2c Mon Sep 17 00:00:00 2001
From: Anthony Fu <anthonyfu117@hotmail.com>
Date: Tue, 26 Jan 2021 14:38:33 +0800
Subject: [PATCH] test: add failed test for #498

---
 test/v3/runtime-core/apiWatch.spec.ts | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/test/v3/runtime-core/apiWatch.spec.ts b/test/v3/runtime-core/apiWatch.spec.ts
index b98d95b3..3e3510e9 100644
--- a/test/v3/runtime-core/apiWatch.spec.ts
+++ b/test/v3/runtime-core/apiWatch.spec.ts
@@ -531,4 +531,30 @@ describe('api: watch', () => {
 
     expect(data2.value).toMatchObject([1])
   })
+
+  // #498
+  it('watchEffect should not lead to infinite loop when accessing', async () => {
+    let dummy = 0
+
+    const state = reactive({
+      data: [],
+      watchVar: 123,
+    })
+
+    watchEffect(() => {
+      // accessing
+      state.watchVar
+      // setting
+      state.data = []
+      dummy += 1
+    })
+
+    expect(dummy).toBe(1)
+
+    state.data = []
+
+    await nextTick()
+
+    expect(dummy).toBe(2)
+  })
 })