RollupError in Nuxt 4 module.

Environment

• Operating System: Windows_NT
• Node Version: v24.7.0
• Nuxt Version: 4.1.1
• CLI Version: 3.28.0
• Nitro Version: 2.12.5
• Package Manager: npm@11.4.1
• Builder: -
• User Config: modules, build
• Runtime Modules: -
• Build Modules: -

Reproduction

Im trying to update my module (https://github.com/Pentadome/nuxt-openAPI-wrapper/tree/nuxt-4) to Nuxt 4. but after updating, whenever i build the playground, i get this rollup error:

(node:456) [DEP0155] DeprecationWarning: Use of deprecated trailing slash pattern mapping "./" in the "exports" field module resolution of the package at C:\Users\user\repos\nuxt-open-api\nuxt-openapi-wrapper\playground\node_modules\@vue\shared\package.json imported from C:\Users\user\repos\nuxt-open-api\nuxt-openapi-wrapper\playground\node_modules\nuxt\dist\core\runtime\nitro\templates\error-dev.js. Mapping specifiers ending in "/" is no longer supported.
(Use `node --trace-deprecation ...` to show where the warning was created)
[plugin inject] playground/node_modules/.cache/nuxt/.nuxt/openapi-wrapper/index.ts: rollup-plugin-inject: failed to parse C:/Users/user/repos/nuxt-open-api/nuxt-openapi-wrapper/playground/node_modules/.cache/nuxt/.nuxt/openapi-wrapper/index.ts. Consider restricting the plugin to particular files via options.include

 ERROR  RollupError: playground/node_modules/.cache/nuxt/.nuxt/openapi-wrapper/index.ts (1:7): Expected '{', got 'type' (Note that you need plugins to import files that are not JavaScript)                                             nitro 15:44:33  


1: export type * from "C:/Users/user/repos/nuxt-open-api/nuxt-openapi-wrapper/dist/runtime/fetchTypes";

Describe the bug

I did not get this error when building for Nuxt 3.

Additional context

No response

Logs

Start by reproducing the Nuxt 4 build in the linked nuxt-openAPI-wrapper playground and inspect the generated .nuxt/openapi-wrapper/index.ts entry point. Read the rollup-plugin-inject failure and compare the Nuxt 3 and Nuxt 4 build paths. Done means the playground build completes without the reported RollupError.