Can't use global .css when using modules with custom options

[StarpTech]

When modules are activated with an object we can't use global CSS because everything is handled as modules.

postcss({
        modules: {
          generateScopedName: '[folder]__[local]',
          scopeBehaviour: 'local'
        },
        extract: true
      })

Input:

import './simple.css';

export default function Button() {
    return <div className={styles.button}></div>
}

.btn {
    color: red;
}

Output:

.Button__btn___yLF_B {
    color: red;
}

Workaround: Don't set custom modules settings.

Proposal:

Enable CSS Modules only on file convention or add a new option to infer the module mode by yourself.
https://github.com/egoist/rollup-plugin-postcss/blob/master/src/postcss-loader.js#L74

[NithinBiliya]

This is also impacting all the projects using microbundle. Noticed it in create-react-library.

[alanrubin]

Same here, want to mix module.scss with plain .scss (global), but unable to do it.

[egoist]

fixed by #292