External composable libraries reactivity broken

[pikax]

Describe the bug

Composable libraries that rely on @vue/runtime-core have their reactivity system broken.

For example vue-composable uses @vue/runtime-core as peerDependency.

When used with vite, because of vite uses the runtime.esm-browser it will include all the reactivity system in one file, making the third-party libraries that rely on runtime-core broken.

System Info

• required vite version: 0.11.1
• required Operating System: Windows 10
• required Node version: 14.1
• Optional:
  • yarn version: 1.22.4
  • Installed vue version: beta.9
  • Installed @vue/compiler-sfc version: beta.9

Reproduction

Install vite and use this component as App.vue

Fixes

This can be fixed by changing the import on the third-party to vue instead of runtime-core.
Ideally I would expect the runtime-core to be a proxy of vue

[yyx990803]

vite actually can directly support the esm-bundler builds, so we should just use it.

[pikax]

Now it works ⚡ thanks ⚡