From 1ca94f0b97dfe6c6e23a327dc2c16c01d7e5d7eb Mon Sep 17 00:00:00 2001
From: btea <2356281422@qq.com>
Date: Mon, 30 Jan 2023 06:56:38 +0000
Subject: [PATCH 1/2] fix: correctly update styles

---
 src/platforms/web/runtime/modules/style.ts   | 2 +-
 test/unit/modules/vdom/modules/style.spec.ts | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/platforms/web/runtime/modules/style.ts b/src/platforms/web/runtime/modules/style.ts
index ff6e14da495..43bde16ef3e 100644
--- a/src/platforms/web/runtime/modules/style.ts
+++ b/src/platforms/web/runtime/modules/style.ts
@@ -91,7 +91,7 @@ function updateStyle(oldVnode: VNodeWithData, vnode: VNodeWithData) {
   }
   for (name in newStyle) {
     cur = newStyle[name]
-    if (cur !== oldStyle[name]) {
+    if (cur !== oldStyle[name] || !el.style[name]) {
       // ie9 setting to null has no effect, must use empty string
       setProp(el, name, cur == null ? '' : cur)
     }
diff --git a/test/unit/modules/vdom/modules/style.spec.ts b/test/unit/modules/vdom/modules/style.spec.ts
index ec57ae88d6e..3e355efa1f8 100644
--- a/test/unit/modules/vdom/modules/style.spec.ts
+++ b/test/unit/modules/vdom/modules/style.spec.ts
@@ -28,6 +28,14 @@ describe('vdom style module', () => {
     expect(elm.style.display).toBe('block')
   })
 
+  it('border related style should update correctly', () => {
+    const vnode1 = new VNode('p', { style: { border: 'border: 10px solid red', 'border-bottom': '10px solid blue' } })
+    const vnode2 = new VNode('p', { style: { 'border-right': '10px solid red', 'border-bottom': '10px solid blue' } })
+    patch(null, vnode1)
+    const elm = patch(vnode1, vnode2)
+    expect(elm.style.borderBottom).toBe('10px solid blue')
+  })
+
   it('should remove elements attrs', () => {
     const vnode1 = new VNode('p', { style: { fontSize: '12px' } })
     const vnode2 = new VNode('p', { style: { display: 'block' } })

From fec64dc3b6caedb85bae7c2750dfb4c3c07df16c Mon Sep 17 00:00:00 2001
From: btea <2356281422@qq.com>
Date: Mon, 30 Jan 2023 15:28:58 +0800
Subject: [PATCH 2/2] chore: update test

---
 test/unit/modules/vdom/modules/style.spec.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/unit/modules/vdom/modules/style.spec.ts b/test/unit/modules/vdom/modules/style.spec.ts
index 3e355efa1f8..9f694a94019 100644
--- a/test/unit/modules/vdom/modules/style.spec.ts
+++ b/test/unit/modules/vdom/modules/style.spec.ts
@@ -29,7 +29,7 @@ describe('vdom style module', () => {
   })
 
   it('border related style should update correctly', () => {
-    const vnode1 = new VNode('p', { style: { border: 'border: 10px solid red', 'border-bottom': '10px solid blue' } })
+    const vnode1 = new VNode('p', { style: { border: '10px solid red', 'border-bottom': '10px solid blue' } })
     const vnode2 = new VNode('p', { style: { 'border-right': '10px solid red', 'border-bottom': '10px solid blue' } })
     patch(null, vnode1)
     const elm = patch(vnode1, vnode2)