Fixes: #38232
Fixes: https://github.com/vercel/next.js/issues/36893
Version [12.1.1-canary.5](https://github.com/vercel/next.js/releases/tag/v12.1.1-canary.5) introduced a bug, more specifically this PR: https://github.com/vercel/next.js/pull/34836
The issue described in #38232 is that the following code starts both the dev and prod servers:
```js
const start = require('next/dist/cli/next-start')
start.nextStart()
```
I searched a bit and found that `lib/get-project-dir.ts#getProjectDir()` now imports `bin/next.ts`
6b8e499c7b/packages/next/lib/get-project-dir.ts (L3)
and it calls a CLI command via
6b8e499c7b/packages/next/bin/next.ts (L137)
This `command` should not be defined, but it fallbacks to `defaultCommand`, which is `dev` (that explains why the dev server is also started)
This PR moves the `cliCommand` types and `commands` variable to a new separate file instead of `bin/next.ts`, to avoid running a CLI command when we import any file that also imports `lib/get-project-dir.ts`
Not sure how integration tests can be added for this issue, but feel free to tell me.
Co-authored-by: JJ Kasper <22380829+ijjk@users.noreply.github.com>
