feat!: support multiline values in env files

[Dunqing]

Description

close: #10149
related PR: #10370

Additional context

---

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines.
• Read the Pull Request Guidelines and follow the Commit Convention.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.

[sapphi-red]

Thanks for splitting the PR!

It would be nice if we could have a better error message for #6858.
TypeError: Cannot read properties of undefined (reading 'split') is quite difficult to understand.
#6858 (comment)

[Dunqing]

@sapphi-red I'm trying to fix TypeError: Cannot read properties of undefined (reading 'split') if you have a better way to fix it, please come to motdotla/dotenv-expand#85 and give me some suggestions. Thanks!

[bluwy]

It would be nice if we could have a better error message for #6858.
TypeError: Cannot read properties of undefined (reading 'split') is quite difficult to understand.
#6858 (comment)

Unless we have a hardcoded error check for the split undefined bug, I think it would be nicer if it's fixed upstream 🤔

[Dunqing]

Unless we have a hardcoded error check for the split undefined bug, I think it would be nicer if it's fixed upstream 🤔

Can we re-implement dotenv-expand in vite?

[bluwy]

I think it's better to keep it upstream for now so it gets bug fixes and we can refer to its docs.

[sapphi-red]

Unless we have a hardcoded error check for the split undefined bug, I think it would be nicer if it's fixed upstream 🤔

Yeah, I think it would be better to be fixed in upstream. But until that get fixed, I think we should improve the error message on our side. Something like:

try {
  expand()
} catch (e) {
  if (e.message.includes('split') {
    throw new Error('dotenv-expand failed to expand env vars. Maybe you need to escape `$`?')
  }
  throw e
}

Without that, I suppose we'll receive many bug reports.

[bluwy]

I'd be fine with a custom error check for now too 👍

[patak-dev]

Let's merge and improve the error message in a follow-up PR. Let us know if you want to take that @Dunqing. I want to include this already in the next patch.

[sapphi-red]

@Dunqing Just to confirm, do you plan to take the error one? I'll take that if you don't.

[Dunqing]

@Dunqing Just to confirm, do you plan to take the error one? I'll take that if you don't.

Sorry, I'll do that soon.

[sapphi-red]

@Dunqing OK. No rush 👍🏼