Dev external dependency is still attempting to be resolved at runtime by import-analysis plugin

[swalker326]

Describe the bug

When you mark a dependency as external via

  resolve: {
    external: ['test-utils'],
  }

then provide the dependency via an import map

    <script type="importmap">
      {
        "imports": {
          "test-utils": "/test-utils.js"
        }
      }
    </script>

The plugin still throws an error saying its unable to resolve the dependency.

Reproduction

https://github.com/swalker326/vite-import-map-testing

Steps to reproduce

pnpm i
pnpm dev

running the project in preview mode works fine though.

pnpm build
pnpm preview

System Info

System:
    OS: macOS 15.6.1
    CPU: (16) arm64 Apple M4 Max
    Memory: 153.94 MB / 64.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.12.0 - ~/.nvm/versions/node/v22.12.0/bin/node
    Yarn: 1.22.22 - ~/.nvm/versions/node/v22.12.0/bin/yarn
    npm: 10.9.2 - ~/.nvm/versions/node/v22.12.0/bin/npm
    bun: 1.1.38 - ~/.bun/bin/bun
    Watchman: 2025.06.30.00 - /opt/homebrew/bin/watchman
  Browsers:
    Brave Browser: 135.1.77.101
    Chrome: 140.0.7339.82
    Safari: 18.6
  npmPackages:
    @vitejs/plugin-react: ^5.0.0 => 5.0.2
    vite: ^7.1.5 => 7.1.5

Used Package Manager

pnpm

Logs

  VITE v7.1.5  ready in 560 ms

  ➜  Local:   http://localhost:5176/
  ➜  Network: use --host to expose
  ➜  press h + enter to show help
1:01:17 PM [vite] (client) Pre-transform error: Failed to resolve import "test-utils" from "src/App.tsx". Does the file exist?
  Plugin: vite:import-analysis
  File: /Users/shanewalker/Developer/vite-import-map-testing/src/App.tsx:6:27
  20 |  import viteLogo from "/vite.svg";
  21 |  import "./App.css";
  22 |  import { greet, add } from "test-utils";
     |                              ^
  23 |  function App() {
  24 |    _s();
1:01:17 PM [vite] Internal server error: Failed to resolve import "test-utils" from "src/App.tsx". Does the file exist?
  Plugin: vite:import-analysis
  File: /Users/shanewalker/Developer/vite-import-map-testing/src/App.tsx:6:27
  20 |  import viteLogo from "/vite.svg";
  21 |  import "./App.css";
  22 |  import { greet, add } from "test-utils";
     |                              ^
  23 |  function App() {
  24 |    _s();
      at TransformPluginContext._formatLog (file:///Users/shanewalker/Developer/vite-import-map-testing/node_modules/.pnpm/vite@7.1.5/node_modules/vite/dist/node/chunks/dep-M_KD0XSK.js:31527:43)
      at TransformPluginContext.error (file:///Users/shanewalker/Developer/vite-import-map-testing/node_modules/.pnpm/vite@7.1.5/node_modules/vite/dist/node/chunks/dep-M_KD0XSK.js:31524:14)
      at normalizeUrl (file:///Users/shanewalker/Developer/vite-import-map-testing/node_modules/.pnpm/vite@7.1.5/node_modules/vite/dist/node/chunks/dep-M_KD0XSK.js:29996:18)
      at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
      at async file:///Users/shanewalker/Developer/vite-import-map-testing/node_modules/.pnpm/vite@7.1.5/node_modules/vite/dist/node/chunks/dep-M_KD0XSK.js:30054:32
      at async Promise.all (index 7)
      at async TransformPluginContext.transform (file:///Users/shanewalker/Developer/vite-import-map-testing/node_modules/.pnpm/vite@7.1.5/node_modules/vite/dist/node/chunks/dep-M_KD0XSK.js:30022:4)
      at async EnvironmentPluginContainer.transform (file:///Users/shanewalker/Developer/vite-import-map-testing/node_modules/.pnpm/vite@7.1.5/node_modules/vite/dist/node/chunks/dep-M_KD0XSK.js:31325:14)
      at async loadAndTransform (file:///Users/shanewalker/Developer/vite-import-map-testing/node_modules/.pnpm/vite@7.1.5/node_modules/vite/dist/node/chunks/dep-M_KD0XSK.js:26407:26)
      at async viteTransformMiddleware (file:///Users/shanewalker/Developer/vite-import-map-testing/node_modules/.pnpm/vite@7.1.5/node_modules/vite/dist/node/chunks/dep-M_KD0XSK.js:27492:20)

Validations

• Follow our Code of Conduct
• 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 vuejs/core instead.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.