🐛 Stylelint: "customSyntax" config is not recognised as dependency usage

[duncan-thacker]

Prerequisites

• [X] I'm using the latest version
• [X] I've read the relevant documentation
• [X] I've searched for existing issues
• [X] I've checked the list of known issues
• [X] I've read the issue reproduction guide

Reproduction url

https://codesandbox.io/p/sandbox/zealous-northcutt-g94nf7

Reproduction access

• [X] I've made sure the reproduction is publicly accessible

Description of the issue

Including "customSyntax": "postcss-less" in the stylelint config does not mark postcss-less as a used dependency. knip definitely detects the config file correctly, but there is nothing in the plugin code that checks this field. https://github.com/webpro-nl/knip/blob/main/packages/knip/src/plugins/stylelint/index.ts

Knip produces the following report:

Unused devDependencies (1)
postcss-less  package.json

Workaround

By switching to a JS config, you can do

"customSyntax": require.resolve("postcss-less")

which causes the dependency to be correctly marked as used.

[duncan-thacker]

I'll try to raise a PR for this at some point, for now it's just a nice-to-have so that knip works better out-of-the-box.

[webpro]

Sounds great, thanks in advance! Let me know if you need anything.