[v8] `import { type Thing }` bundles unused deps, while `import type {Thing}` does not. (It was not the case in v7)

[feychenie]

Describe the bug

I have a module importing a package, and exporting a type unrelated to this import, and a dummy function just to mark the imported package as used somewhere:

// ReproModule.ts
import * as Invariant form 'ts-invariant'

export type SomeType = { name: string };

export function someFunction() {
  throw new Invariant.InvariantError("THIS SHOULD NOT BE BUNDLED")
}

(someFunction is not imported anywhere in the code)

When I import the type using import type { SomeType } from './ReproModule', ts-invariant is not bundled, as expexted.

However, when i change the import to import { type SomeType } from './ReproModule, then the package ts-invariant and all it's deps get bundled in the build, which i believe is not as expected (and was not an issue in Vite 7)

Reproduction

https://github.com/feychenie/repro-vite8-type-only-imports-bundling-issue

Steps to reproduce

• Clone the repo, run pnpm install, run pnpm build.
• Notice that the type import in IssueComponent.tsx has this format: import type { SomeType } from ...
• Inspect the build output, or open the vite devtools UI and notice ts-invariant is not bundled, as expected.

• change the type import in IssueComponent.tsx to import { type SomeType } from ... and build again.
• notice in the build output or in the devtools ui that the ts-invariant is not bundled, also tslib

System Info

System:
    OS: macOS 26.4
    CPU: (10) arm64 Apple M1 Pro
    Memory: 69.20 MB / 32.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 24.13.0 - /Users/feychenie/.nvm/versions/node/v24.13.0/bin/node
    npm: 11.6.2 - /Users/feychenie/.nvm/versions/node/v24.13.0/bin/npm
    pnpm: 10.12.4 - /Users/feychenie/Library/pnpm/pnpm
    Deno: 2.5.6 - /Users/feychenie/.deno/bin/deno
  Browsers:
    Brave Browser: 146.1.88.138
    Chrome: 146.0.7680.178
    Firefox: 137.0
    Safari: 26.4
  npmPackages:
    @vitejs/devtools: ^0.1.13 => 0.1.13
    @vitejs/plugin-react: ^6.0.1 => 6.0.1
    vite: ^8.0.8 => 8.0.8

Used Package Manager

pnpm

Logs

No response

Validations

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• Read the Contributing Guidelines.
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• The provided reproduction is a minimal reproducible example of the bug.

[sapphi-red]

This is an expected behavior because you have verbatimModuleSyntax enabled in the tsconfig. When that option is enabled, import { type SomeType } from './ReproModule' is transformed to import './ReproModule' (import type { SomeType } from './ReproModule' is removed regardless of that option).

It has the same behavior in v7 as well: https://stackblitz.com/edit/github-r2xs21wm?file=src%2FIssueComponent.tsx&terminal=build
(" (see https://github.com/apollographql/invariant-packages)" that comes from ts-invariant exists in dist/index-hash.js)

[bhuynhdev]

Hmm the official Typescript docs you linked says

TypeScript 5.0 introduces a new option called --verbatimModuleSyntax to simplify the situation.

// Rewritten to 'import {} from "xyz";'
import { type xyz } from "xyz";

Should import { type xyz } from "xyz" be different from import './xyz', as in the former would supposedly be tree-shaken away, whereas the latter incorrectly imports whole module while only the types are being used.

[sapphi-red]

import {} from "xyz" and import "xyz" is equivalent in JS.