Deploy failed due to an error in netlify-plugin-inline-functions-env plugin

I successfully deployed once my site. I have a netlify function using stripe. I’m making yarn install before building the whole project. It says it cannot find stripe even though i’m using the command:
cd functions && yarn install && cd .. && yarn build && gulp build. I have a package.json in the functions dir mentioning stripe. What’s wrong ?

This feels like a hack. This is not how you build functions. Functions are automatically built.

You need to add all function dependencies to your root package.json and Netlify will bundle the functions automatically. No need to cd here && cd there.