Any warning about build.outDir？

[CHOYSEN]

Is your feature request related to a problem? Please describe.
If user careless setting it like . or ../, Vite will remove all files in that directory⛔⛔⛔

vite/packages/vite/src/node/build.ts

Line 322 in ae2e14b

emptyDir(outDir)

Describe the solution you'd like
Only empty folder are allowed at the first time, then put a hidden file in this directory as a sign after build?

I think there should be at least a warning when outDir outside of the Vite project!!