fix(TransitionGroup): use offsetLeft and offsetTop instead of getBoundingClientRect to avoid transform scale affect animation

packages/runtime-dom/src/components/TransitionGroup.ts

@@ -29,8 +29,13 @@ import {
 } from '@vue/runtime-core'
 import { extend } from '@vue/shared'
 
-const positionMap = new WeakMap<VNode, DOMRect>()
-const newPositionMap = new WeakMap<VNode, DOMRect>()
+interface Position {
+  top: number
+  left: number
+}
+
+const positionMap = new WeakMap<VNode, Position>()
+const newPositionMap = new WeakMap<VNode, Position>()
 const moveCbKey = Symbol('_moveCb')
 const enterCbKey = Symbol('_enterCb')
 
@@ -145,10 +150,10 @@ const TransitionGroupImpl: ComponentOptions = /*@__PURE__*/ decorate({
                 instance,
               ),
             )
-            positionMap.set(
-              child,
-              (child.el as Element).getBoundingClientRect(),
-            )
+            positionMap.set(child, {
+              left: (child.el as HTMLElement).offsetLeft,
+              top: (child.el as HTMLElement).offsetTop,
+            })
           }
         }
       }
@@ -189,7 +194,10 @@ function callPendingCbs(c: VNode) {
 }
 
 function recordPosition(c: VNode) {
-  newPositionMap.set(c, (c.el as Element).getBoundingClientRect())
+  newPositionMap.set(c, {
+    left: (c.el as HTMLElement).offsetLeft,
+    top: (c.el as HTMLElement).offsetTop,
+  })
 }
 
 function applyTranslation(c: VNode): VNode | undefined {

packages/vue/__tests__/e2e/TransitionGroup.spec.ts

@@ -646,6 +646,62 @@ describe('e2e: TransitionGroup', () => {
     E2E_TIMEOUT,
   )
 
+  // #6105
+  test(
+    'with scale',
+    async () => {
+      await page().evaluate(() => {
+        const { createApp, ref, onMounted } = (window as any).Vue
+        createApp({
+          template: `
+            <div id="container">
+              <div class="scale" style="transform: scale(2) translateX(50%) translateY(50%)">
+                <transition-group tag="ul">
+                  <li v-for="item in items" :key="item">{{item}}</li>
+                </transition-group>
+                <button id="toggleBtn" @click="click">button</button>
+              </div>
+            </div>
+          `,
+          setup: () => {
+            const items = ref(['a', 'b', 'c'])
+            const click = () => {
+              items.value.reverse()
+            }
+
+            onMounted(() => {
+              const styleNode = document.createElement('style')
+              styleNode.innerHTML = `.v-move {
+                transition: transform 0.5s ease;
+              }`
+              document.body.appendChild(styleNode)
+            })
+
+            return { items, click }
+          },
+        }).mount('#app')
+      })
+
+      const original_top = await page().$eval('ul li:nth-child(1)', node => {
+        return node.getBoundingClientRect().top
+      })
+      const new_top = await page().evaluate(() => {
+        const el = document.querySelector('ul li:nth-child(1)')
+        const p = new Promise(resolve => {
+          el!.addEventListener('transitionstart', () => {
+            const new_top = el!.getBoundingClientRect().top
+            resolve(new_top)
+          })
+        })
+        ;(document.querySelector('#toggleBtn') as any)!.click()
+        return p
+      })
+
+      expect(original_top).toBeLessThan(new_top as number)
+    },
+    E2E_TIMEOUT,
+  )
+
   test(
     'not leaking after children unmounted',
     async () => {