Vue version

3.2.45

Link to minimal reproduction

https://sfc.vuejs.org/#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

Steps to reproduce

点击按钮会触发子组件渲染，vue2不会

What is expected?

样式未变时子组件不重新渲染

What is actually happening?

样式未变时子组件会重新渲染

System Info

No response

Any additional comments?

No response

You are recreating a new object for style on every re-render of the parent, and the parent re-renders on each change of count.

This is expected in Vue 3, where applying fallthrough attributes is left to the child instead of being done by the parent.