[Bug Report][3.5.17] Vuetify can't be installed in an existing project that's using vue-i18n@8.x.x

[pcoterecollective]

Environment

Vuetify Version: 3.5.17
Vue Version: 3.4.26
Browsers: Chrome 124.0.0.0
OS: Mac OS 10.15.7

Steps to reproduce

• Clone repo and install dependencies using npm;
• Run npm i vuetify in terminal;

Expected Behavior

Vuetify should be installed without any issues;

Actual Behavior

Vuetify installation fails with the following error:

npm ERR! code ERESOLVE
npm ERR! ERESOLVE could not resolve
npm ERR! 
npm ERR! While resolving: vuetify@3.5.17
npm ERR! Found: vue-i18n@8.25.1
npm ERR! node_modules/vue-i18n
npm ERR!   vue-i18n@"^8.25.1" from the root project
npm ERR! 
npm ERR! Could not resolve dependency:
npm ERR! peerOptional vue-i18n@"^9.0.0" from vuetify@3.5.17
npm ERR! node_modules/vuetify
npm ERR!   vuetify@"*" from the root project
npm ERR! 
npm ERR! Conflicting peer dependency: vue-i18n@9.13.1
npm ERR! node_modules/vue-i18n
npm ERR!   peerOptional vue-i18n@"^9.0.0" from vuetify@3.5.17
npm ERR!   node_modules/vuetify
npm ERR!     vuetify@"*" from the root project
npm ERR! 
npm ERR! Fix the upstream dependency conflict, or retry
npm ERR! this command with --force or --legacy-peer-deps
npm ERR! to accept an incorrect (and potentially broken) dependency resolution.
npm ERR!
...

Reproduction Link

https://github.com/pcoterecollective/vuetify-issue

Other comments

• This issue is caused by the fact that vuetify has a peer dependency on vue-i18n@^9.0.0, while the root project has a dependency on vue-i18n@^8.25.1. This causes a conflict between the two versions of vue-i18n and the installation fails;
• Using --force or --legacy-peer-deps flags is not a good solution, as it may lead to potential issues in the future AND/OR may not be an option for all dev/prod servers;
• Vuetify cannot be considered as an option fur our projects because of that;

[johnleider]

What's the fix? Remove the optional peer dependency? I figured that it would be true to its name.

[KaelWD]

Does vue-i18n 8 even work with vue 3?

I figured that it would be true to its name.

It just means that if it's installed it should match a certain range, they aren't necessarily using any code that interfaces between vue-i18n and vuetify though.

[pcoterecollective]

vue-i18n@8.x.x does work with Vue 3. We're already using it in some Vue 3 projects.

The reason why we couldn't upgrade to vue-i18n@9.x.x is that it's no longer supporting custom formatters which we make an extensive use of in our projects. According to their documentation, this feature will only be re-implemented in next major release.