[Nuxt 3.9] - Hydration STYLE mismatch

[mkierdev]

Environment

Nuxt 3.9

Reproduction

I tried to upgrade from 3.8.2 to 3.9 using nuxi upgrade

Describe the bug

I've run into issue that was not present in 3.8.2:

Hydration style mismatch on < div class...>​…​​ // etc, replaced upon pasting

• rendered on server: style="font-size:16px;--spacing:12px;"
• expected on client: style="font-size: 16px; --spacing: 12px"

What's even more weird is that these properties actually comes from simple props with default values:
(Component simplified for showcase)

withDefaults(defineProps<Props>(), {
  width: 16,
  spacing: 12,
});

<div :style="`font-size: ${width}px; --spacing: ${spacing}px`" />

In another component, if style is generated by computed(), it also returns hydration style mismatch.

Additional context

No response

Logs

No response

[manniL]

Be aware that Vue 3.9 added more fine-grained hydration info. That issue could've been there for long but was simply undetected. For more insights you have to provide a reproduction ;)

[github-actions]

Would you be able to provide a reproduction? 🙏

More info

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[josuelrocha]

It really seems to be a bug in Nuxt 3.9, in the example below, when you have :style and also v-show to modify the style, the Hydration warning is displayed.

Example to reproduce

Anywhere in a Nuxt 3.9 project, place this code

<div v-show="false" :style="{ width: 'auto' }">test</div>

Console warn

[Vue warn]: Hydration style mismatch on 
<div style="width:auto;display:none;"> 
  - rendered on server: style="width:auto;display:none;"
  - expected on client: style="width:auto;"

[mkierdev]

Moreover, if you are returning default 'server' styles and modify it on the client during first load (ex. When accessing client window and calculating some stuff based on it) you also have this warning. Does not seems good.

[manniL]

Can you try reproducing this in https://stackblitz.com/github/nuxt-contrib/vue3-ssr-starter/tree/main?terminal=dev ? Might be an upstream issue.

[josuelrocha]

Really, the problem seems to be coming from Vue and not Nuxt.

https://stackblitz.com/edit/github-dyqiua?file=src%2Fpages%2FHome.vue

[manniL]

Let's track in vuejs/core#10006