feat: improve dynamic import variable failure error message

[btea]

Description

As shown in the figure below, when the dynamic import component fails, the error message Unknown variable dynamic import: ./components/a/b/test.vue will appear.

But judging from the code structure, there is no problem with the path. I think this information may not be enough for people to immediately and clearly determine where the problem occurs, so outputting pattern information may be able to explain the problem more clearly and help users locate the problem more quickly.

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[bluwy]

I think in general, we want to hide import.meta.glob as an implementation detail of dynamic imports only, so exposing it in the error message could be more confusing?

IIUC the issue is that some may forgot that ${var} cannot contain slashes. Could we detect cases like this in the error message instead? (maybe checking number of /). Or I suppose linking directly to https://vitejs.dev/guide/features.html#dynamic-import could be fine too. We need to also make sure to not make the helper code too large as it's injected to the runtime.

[btea]

It makes sense, I just noticed that the document states Note that variables only represent file names one level deep.

Maybe we can add the variable inclusion level depth may be more than one, please refer to https://vitejs.dev/guide/features.html#dynamic-import in the error message.

[bluwy]

I think maybe directly appending Note that variables only represent file names one level deep should also be fine. It would be nice to optionally show it if we know it happens, but if not it also works for me.

The link currently doesn't have a lot of information, so might not be worth adding it for now.

[bluwy]

Seems to work locally for me 👍 Curious to hear what others think of this extra code added before merging it.

[patak-dev]

I'm good with the added param. Another option is to add a link that is always there and explain more in the docs. Or reword it as a tip but it may confuse more than it helps.

[btea]

Maybe we can add a detailed explanation chapter about this situation to the troubleshooting page in the future.