L-1016 By default, don't check ENV vars in Vercel non-production build

[PetrHeinz]

Resolves #6 when building project via vercel build while not having VERCEL_ENV variable accessible during build.

[curusarn]

Could you test this by running vercel build to make sure we don't show the warnings? 🙏

[PetrHeinz]

@curusarn That's what I did even before #14, worked as intended with example project on my machine. There's just too many variables to ensure others will have the same experience...

Here's full output for possible use in the future:

Petrs-MacBook-Pro:logger petrheinz$ vercel build
Vercel CLI 32.5.6
WARNING: You should not upload the `.next` directory.
Installing dependencies...

up to date in 1s

124 packages are looking for funding
  run `npm fund` for details
Detected Next.js version: 14.0.2
Detected `package-lock.json` generated by npm 7+
Running "npm run build"

> build
> next build

 ✓ Linting and checking validity of types    
   ▲ Next.js 14.0.2

 ⚠ /api/edge provided runtime 'experimental-edge'. It can be updated to 'edge' instead.
 ✓ Creating an optimized production build    
 ✓ Compiled successfully
 ⚠ You are using an experimental edge runtime, the API might change.
 ✓ Collecting page data    
 ✓ Generating static pages (3/3) 
 ✓ Collecting build traces    
 ✓ Finalizing page optimization    

Route (pages)                              Size     First Load JS
┌ ● /                                      4.92 kB        91.5 kB
├   /_app                                  0 B            86.5 kB
├ ○ /404                                   182 B          86.7 kB
├ ℇ /api/edge                              0 B            86.5 kB
├ λ /api/hello                             0 B            86.5 kB
└ λ /serverSideProps                       407 B          86.9 kB
+ First Load JS shared by all              86.5 kB
  ├ chunks/framework-66d32731bdd20e83.js   45.2 kB
  ├ chunks/main-8c2fcf961f1eeec3.js        31.8 kB
  ├ chunks/pages/_app-9cf4ffac8ca82c92.js  8.75 kB
  └ chunks/webpack-59c5c889f52620d6.js     819 B

ƒ Middleware                               36.8 kB

○  (Static)        prerendered as static content
●  (SSG)           prerendered as static HTML (uses getStaticProps)
λ  (Dynamic)       server-rendered on demand using Node.js
ℇ  (Edge Runtime)  server-rendered on demand using the Edge Runtime

Traced Next.js server files in: 237.505ms
Created all serverless functions in: 95.793ms
Collected static files (public/, static/, .next/static): 1.594ms
✅  Build Completed in .vercel/output [7s]

[PetrHeinz]

@curusarn I hope @jakeleventhal will verify that it works in their use case as well, so we know we're in the clear before releasing another small fix 🙂

⏳ I'm waiting with merging it for the time being...

[jakeleventhal]

@PetrHeinz #6 (comment)