Tree shaking/Code splitting is failing with import { type } syntax

[AlexandreBonaventure]

Describe the bug

Hello, we've been noticing an issue with tree-shaking since vite@2.8.0. I tracked the issue down to the esbuild upgrade here: #5861 and even more specifically to this issue evanw/esbuild#1525
The whole issue only happens because we're using "preserveValueImports": true in our json config. It historically helped us get rid of some errors with some types when used in Vue template SFC.
Reading through https://www.typescriptlang.org/tsconfig#preserveValueImports we thought it was a good default (even though it is not set in official create-vite app, but that's another topic).

Anyways, I think repro steps below highlight the issue nonetheless, I thought it was more an esbuild issue at first, but I didn't manage to repro with only esbuild. I believe here that's because rollup is ultimately doing the treeshaking?

Repro

Given a component like

<script setup lang="ts">
import { type Map } from 'mapbox-gl';

let MyMap:Map

(async () => {
  MyMap = new (await import('mapbox-gl')).Map
})();
</script>

With import { type Map } from 'mapbox-gl';` tree shaking fails:

With import type { Map } from 'mapbox-gl';` tree shaking succeeds:

The expected result is that both syntax should allow code splitting.

Reproduction

https://github.com/AlexandreBonaventure/vite-import-type-bug
(I kept mapbox in the repro since it is easier to spot if code splitting happen)

System Info

not relevant

Used Package Manager

yarn

Logs

No response

Validations

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• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to https://github.com/vuejs/core instead.
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• The provided reproduction is a minimal reproducible example of the bug.

[sapphi-red]

I was able to reproduce only with esbuild.
For example, think about this code.

import { type Map } from 'mapbox-gl';

let MyMap:Map

When preserveValueImports is true, it becomes:

import {} from "mapbox-gl";
let MyMap;

"preserveValueImports":true (esbuild repl) "preserveValueImports":true (ts playground)

When preserveValueImports is false, it becomes:

let MyMap;

"preserveValueImports":false (esbuild repl) "preserveValueImports":false (ts playground)

It seems to be a bug in esbuild because the behavior differs from TypeScript compiler.
I thought a bit strange about the TS compiler's behavior at first, but it seems intended.

[AlexandreBonaventure]

Oh nice thanks ! I probably was not able to reproduce because I was using the bundle api rather than the transform.
It's fine if I share your findings in the esbuild repo ? Or you prefer to create a ticket yourself ?

[sapphi-red]

Feel free to create an issue with my findings. 👍

[AlexandreBonaventure]

Closing because it is an upstream bug