bundle file does not include compile function and template cannot be compiled even vue is aliased as 'vue/dist/vue.esm-bundler.js'

[yamacent]

Version

3.0.0-beta.14

Reproduction link

https://github.com/yamacent/vue-next-minimal-reproduction-tree-shaking

Steps to reproduce

$ git clone git@github.com:yamacent/vue-next-minimal-reproduction-tree-shaking.git
$ cd vue-next-minimal-reproduction-tree-shaking
$ npm install
$ npx webpack

# open dist/index.html in the browser and nothing will be shown

# un-comment `console.log(compile)` in `src/index.js`
$ npx webpack

# open dist/index.html again and `hello` will be shown this time

What is expected?

hello is shown even console.log(compile) does not exist

What is actually happening?

nothing is shown when console.log(compile) does not exist

---

Tree Shaking may be the cause.
https://webpack.js.org/guides/tree-shaking/

if sideEffects is set to true, it works fine.
https://github.com/vuejs/vue-next/blob/master/packages/vue/package.json#L10

[underfin]

Yeah.https://github.com/vuejs/vue-next/blob/master/packages/vue/src/index.ts#L72 registerRuntimeCompiler(compileToFunction) is an sideEffect for webpack build this.

See webpack/webpack#10978 (comment). Maybe we should change sideEffect: true for has internal evalution exports.