fix(config)!: support development build

[bluwy]

Description

Followup to #10996. #10996 makes build run in production NODE_ENV by default regardless of mode. Since Vite only supports NODE_ENV=production in .env files, there's no way for a user to build in development NODE_ENV.

This PR removes support for NODE_ENV=production, but added support for NODE_ENV=development only. Allowing development builds.

Additional context

Context: Previously in Vite 3, if the user sets --mode staging, it builds in development NODE_ENV which wasn't a nice default so #10996 changed it.

I didn't add support for NODE_ENV=production as it doesn't make sense in most case. It's only useful for dev command, but production NODE_ENV typically don't work well with the dev command.

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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• Read the Pull Request Guidelines and follow the Commit Convention.
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[benmccann]

Why do we need a restriction on not using production NODE_ENV during development? Is it something in Vite core that would break or some plugin in the ecosystem? I think it'd be nice if we could remove this restriction, but at the very least, if we're going to keep it, I think we should log a warning that we're ignoring the user setting rather than doing it silently.

[bluwy]

We're not supporting production NODE_ENV in dev because it breaks HMR with the Vue plugin (last I tested it reads NODE_ENV in the compiler). Adding a warning sounds like a good idea.

[benmccann]

If it's just the Vue plugin that breaks, can we move the error there? I'm not sure we need to disallow it for everyone else

[bluwy]

That might be a solution too. I guess we could still support NODE_ENV=production, but I'm not sure if there's a usecase for it especially in dev, we're still injecting dev related stuff that doesn't represent prod.

[benmccann]

I imagine people could have some code like if (import.meta.env.PROD) that would be nice to test without having to do a whole vite build each time they tweak it

[patak-cat]

I prefer that we allow NODE_ENV production during dev once we have a real use case. The warning making this a non-feature so people don't start relying on it seems like a safer choice at this point. @bluwy feel free to merge if you are ok with this 👍🏼

[benmccann]

Ok. Sounds fine to me. I did have one suggestion to add a comment above to explain it, but otherwise lgtm

[patak-cat]

If we add a comment, I think we should add a more generic comment, like Blu's message:

We're not supporting production NODE_ENV in dev because it could break HMR in some frameworks (i.e. the Vue Plugin)