Vercel development env crashes startup

Environment

System: OS: macOS 12.3.1 CPU: (10) arm64 Apple M1 Max Memory: 2.65 GB / 32.00 GB Shell: 5.8 - /bin/zsh Binaries: Node: 14.19.1 - ~/.asdf/installs/nodejs/14.19.1/bin/node npm: 8.6.0 - ~/.asdf/plugins/nodejs/shims/npm Browsers: Firefox: 98.0.2 Safari: 15.4 npmPackages: next: ^12.1.4 => 12.1.4 next-auth: ^4.3.1 => 4.3.1 react: ^17.0.2 => 17.0.2

Reproduction URL

https://github.com/reconbot/next-auth-example

Describe the issue

When you run vercel pull you get empty vercel env vars which crashes next on startup

# .env Created by Vercel CLI
VERCEL="1"
VERCEL_ENV="development"
VERCEL_URL=""
VERCEL_GIT_PROVIDER=""
VERCEL_GIT_REPO_SLUG=""
VERCEL_GIT_REPO_OWNER=""
VERCEL_GIT_REPO_ID=""
VERCEL_GIT_COMMIT_REF=""
VERCEL_GIT_COMMIT_SHA=""
VERCEL_GIT_COMMIT_MESSAGE=""
VERCEL_GIT_COMMIT_AUTHOR_LOGIN=""
VERCEL_GIT_COMMIT_AUTHOR_NAME=""

By process of elimitation the only problem line is

VERCEL_URL=""

which causes errors because ?? doesn’t behave as if the env var is missing.

The error is

TypeError [ERR_INVALID_URL]: Invalid URL
    at new NodeError (node:internal/errors:371:5)
    at onParseError (node:internal/url:552:9)
    at new URL (node:internal/url:628:5)
    at parseUrl (/Users/wizard/src/next-auth-example/node_modules/next-auth/lib/parse-url.js:18:16)
    at Object.<anonymous> (/Users/wizard/src/next-auth-example/node_modules/next-auth/react/index.js:70:34)
    at Module._compile (node:internal/modules/cjs/loader:1103:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1155:10)
    at Module.load (node:internal/modules/cjs/loader:981:32)
    at Function.Module._load (node:internal/modules/cjs/loader:822:12)
    at Module.require (node:internal/modules/cjs/loader:1005:19) {

The error seems to be coming from parseUrl which might be from this call or this call. We use ?? a lot of places but if an env var is set but an empty string that doesn’t do the desired behavior.

How to reproduce

Run in order

git clone https://github.com/reconbot/next-auth-example # cone the repo
cd next-auth-example
vercel # go ahead and create a project and deploy it
# double check that `System Environment Variables` is enabled
vercel pull
npm i
npm run dev

Expected behavior

It doesn’t crash

[reconbot]

As a user I have no control over vercel adding these empty string to my local env. This empty string vs undefined issue is old as time for every language and environment. Best to be friendly here imho.

[reconbot]

I’m not sure I agree there’s an offending line, one that’s produced by the build and hosting tooling and not the user. (If they remove it, it will come back)

But handle the condition 💯