Incompatibility with Vue Vapor

[ThatOneCalculator]

Reporting a bug?

Attempting to do

<script setup vapor lang="ts">
import { useI18n } from "vue-i18n";

const { t } = useI18n();
</script>

Results in

Uncaught (in promise) SyntaxError: Must be called at the top of a `setup` function
    createCompileError message-compiler.mjs:77
    createI18nError vue-i18n.runtime.mjs:63
    useI18n vue-i18n.runtime.mjs:2138
    setup ThisFile.vue:3

Expected behavior

Works in Vue Vapor as it does with non-Vapor Vue

Reproduction

None

System Info

"@intlify/unplugin-vue-i18n": "^6.0.8",
"vue": "^3.6.0-alpha.1",
"vue-i18n": "^11.1.10",
"vite": "^7.0.5",

Screenshot

No response

Additional context

https://github.com/vuejs/core/releases/tag/v3.6.0-alpha.1#about-vapor-mode

Validations

• Read the Contributing Guidelines
• Read the Documentation
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussions

[wsxiaolin]

I encountered the same issue using 3.6.0-alpha.2

[hytallenxu-sama]

true, m2

[Jamesits]

Same problem with Vue 3.6.0-alpha.2, vue-i18n either 12.0.0-alpha.3 or 11.1.11

[BobbieGoede]

Some Vue features are not supported in Vapor Mode as described in the "About Vapor Mode" section in https://github.com/vuejs/core/releases/tag/v3.6.0-alpha.1#about-vapor-mode.

Unfortunately one of the unsupported Vue methods in Vapor mode is getCurrentInstance(), which will always return null in Vapor mode. This happens to be how vue-i18n retrieves its instance or sets it up if none is found, so this will need to be reworked if we want to support Vapor mode (not sure what the best approach would be /cc @kazupon).

Other plugins/frameworks will have to figure out how to work around this as well, linking nuxt/nuxt#32859 in case any progress is made and could be learned from.

[kazupon]

I will discuss with the team whether vapor mode can continue to support getCurrentInstance as before, while also exploring other possible solutions.

I am currently working on the release of gunshi v0.27, a side project, and once that is complete, I plan to restart on vue-i18n v12.