Version

3.1.1

Reproduction link

https://github.com/DorianGrey/vue-ts-playground/tree/cypress-ts

Node and OS info

Node 10.13 / yarn 1.12.1 / Manjaro 18

Steps to reproduce

• Checkout the repository branch mentioned above
• yarn
• yarn lint

(Sorry it's not that minimal, but the required parts should be easy to find).

What is expected?

The linter should only pick up the files referenced by the typescript project, extended by .vue files in src.

As a result, yarn lint should not end up with any errors, like using tslint for the same purpose does.

What is actually happening?

Running yarn lint will yield an error like this:

 vue-cli-service lint --fix && stylelint "src/**/*.{scss,vue}"
 ERROR  FatalError: 
Invalid source file: [...]/tests/e2e/specs/test.ts. Ensure that the files supplied to lint have a .ts, .tsx, .d.ts, .js or .jsx extension.

On the branch linked above, I've followed the cypress doc for adding typescript support for the E2E spec files: https://docs.cypress.io/guides/tooling/typescript-support.html
(The default setup failed with a similar error as mentioned here: #2903)
For details about the changes made, see: https://github.com/DorianGrey/vue-ts-playground/pull/12/files

To get this working, it is required to create a separate typescript project that only covers the tests/e2e folder, due to different target and types requirements. Thus, it is also required to exclude this folder in the root project. However, the linter as configured by @vue/cli-plugin-typescript uses a hard-coded list of file patterns if none provided, and those also cover the tests/unit and tests/e2e folders: