Getting 'Cannot read properties of undefined (reading 't')' error in core-base.mjs::formatParts

[LZTWilliam]

Reporting a bug?

After upgrading vue-i18n from 9.2.2 to 9.10.1, and run my application in production mode, I get error while calling i18n.t API as below.

import i18n from 'somewhere createI18n'
i18n.global.t('my_i18n_key')

For now, I locating the difference between the scenario is in the function messageCompiler in core-base.mjs.

1. Before upgrading
   messageCompiler returns new Function(`return ${code}`)() which directly returns my translated message (which is a plain string)
   

2. After upgrading, dev mode
   messageCompiler returns () => message which also returns translated message directly
   

3. After upgrading, production mode
   messageCompiler returns format(message) which leads to (ctx) => formatParts(ctx, ast). And when formatParts is invoked, the parameter ast is just my message string, which cause the error report.
   

Is this the expected behavior? Or should I do some other configuration to allow my plain text is properly translated?

Expected behavior

No error occurs

Reproduction

Still trying. No nuxt, no SSR in my case

System Info

System:                                                
    OS: Windows 10 10.0.19045                            
    CPU: (12) x64 Intel(R) Core(TM) i7-8700 CPU @ 3.20GHz
    Memory: 6.47 GB / 31.84 GB                           
  Binaries:                                              
    Node: 18.14.1 - D:\Program Files\nodejs\node.EXE     
    npm: 8.19.4 - D:\Program Files\nodejs\npm.CMD        
  Browsers:                                              
    Chrome: 122.0.6261.129
    Edge: Chromium (123.0.2420.81)
    Internet Explorer: 11.0.19041.3636

Screenshot

No response

Additional context

No response

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

[github-actions]

Thank you for your feadback!
Would you be able to provide a reproduction 🙏

More info

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[LZTWilliam]

@kazupon While working on minimal production I find wierd thing. The message compiler registration is different between vue-i18n.cjs and vue-i18n.mjs

// vue-i18n.mjs
// register message compiler at vue-i18n
if (__INTLIFY_JIT_COMPILATION__) {
    registerMessageCompiler(compile);
}
else {
    registerMessageCompiler(compileToFunction);
}

// vue-i18n.cjs
// register message compiler at vue-i18n
{
    coreBase.registerMessageCompiler(coreBase.compile);
}

In my minimal reproduction project the mjs file is invoked, and run registerMessageCompiler(compileToFunction);, everything alright.
In my production project the cjs file is invoked(maybe because of webpack and babel?), the compiler is different from the one registered in mjs.

Shouldn't the code be same in mjs and cjs? Does the cjs lack the (__INTLIFY_JIT_COMPILATION__) branch? Looking for reply, thx.

Reproduction

Just require the vue-i18n.cjs can reproduct this issue

[kazupon]

Thank you for your reporting!

Just require the vue-i18n.cjs can reproduct this issue

I think that you don't setup @intlify/unplugin-vue-i18n
You can setup with it.
https://vue-i18n.intlify.dev/guide/advanced/sfc.html#configure-plugin-for-webpack

your project uses Vue CLI, this documentation will be helpful.
https://cli.vuejs.org/guide/webpack.html#simple-configuration