Description of the bug

The issue concerns multi-module repositories using npm monorepo and hoisted dependencies installation. Consider the directory structure:

• package.json — main file
• node_modules/ — common npm dependencies
• packages/ts/my-component/ — frontend component using Vaadin web component dependencies
• packages/java/vaadin-app/ — the Vaadin application
  • packages/java/vaadin-app/package.json — Vaadin app dependencies
  • packages/java/vaadin-app/node_modules/ — app specific npm dependencies

In a setup like that, Vaadin web component dependencies get “hoisted”, e. g., installed in the common upper node_modules directory for ultimately being shared between my-component and vaadin-app. So even though a package is listed in packages/java/vaadin-app/package.json, it could be actually installed to node_modules/

The Hilla repository is using a setup like that. Some IT projects in the Hilla repository fail with the following error:

Error:  The build process encountered an error: Could not execute build-frontend goal Error occured during goal execution: 

  Failed to find the following css files in the `node_modules` or `.../hilla/packages/java/tests/spring/react-i18n/src/main/frontend` directory tree:
      - @vaadin/vaadin-lumo-styles/lumo.css

The @vaadin/vaadin-lumo-styles package is installed in the common node_modules/, whereas Flow is expecting it to be in the app-specific directory.

Expected behavior

Flow using Node resolution rules when locating frontend packages and is able to use hoisted installation. This would be aligned with Vite and other Node-based tools.

Minimal reproducible example

See PR build: https://github.com/vaadin/hilla/actions/runs/16906563241/job/47897784956?pr=3871#step:7:1809

Versions

• Vaadin / Flow version: 25.0-SNAPSHOT
• Java version:
• OS version:
• Browser version (if applicable):
• Application Server (if applicable):
• IDE (if applicable):