"[Vue warn]: Missing required prop" but default value is defined

[WebMechanic]

Hello,

I'm testing with Vue 3.2.47, Vitest 0.28.4 and Happy DOM 8.2.6.

I have several components with a required string property and a default value assigned and get this message in the terminal / console if the prop is not provided. However, it renders correctly in both the browser and happy DOM and the default value is used if I check in Devtools.

[Vue warn]: Missing required prop: "seats"
  at <Widget ident="42" ref="VTU_COMPONENT" >
  at <VTUROOT>

The unit test

const properties = { ident: '42' }; // other props omitted for reasons
const wrapper = await mount(Widget, { props: properties });
// returns '42' and '2' the default value
const { ident, seats } = wrapper.props();

const widget = wrapper.get('.table-widget');
// both assertions pass
expect(widget.element.dataset.ident).toBe(properties.ident);
expect(widget.element.dataset.seats).toBe(seats);

The component part

// <script setup>
const stringRequired = {
	type: String,
	required: true,
};
const $props = defineProps({
	ident: stringRequired,
	seats: { ...stringRequired, default: '2' },
});
const compAttribs = {
	'data-ident': $props.ident,
	'data-seats': $props.seats,
};

<template>
<div ref="widget" v-bind="compAttribs"> </div>
</template>

<!-- eventually renders as expected -->
<div ref="widget" data-ident="42" data-seats="2"> </div>

Why am I getting a "[Vue warn]: Missing required prop" despite a default value is defined and even used in the output. That's what a default is for. Why this unnecessary warning?

Thanks.

[rudyxu1102]

Related to vuejs/vue#7720

[WebMechanic]

Thank you @rudy-xhd.
While this issue from 2018 explains why, it doesn't help me (nor the OP from back then) to solve the "logical issue" I'm also facing :D