(Potential) Bug with getLocalIdent function refactor

[benmvp]

• Operating System: macOS 10.15.5
• Node Version: 12.18.3
• NPM Version: 6.14.6
• webpack Version: 4.44.2
• css-loader Version: 4.3.0

Expected Behavior

This PR by @evilebottnawi changed the content being passed to interpolateName (in loader-utils) from including a plus + to including \x00.

The PR doesn't give an explanation for why this part of the change was made, but as a result upgrading to css-loader v4 or higher breaks my integration with babel-plugin-react-css-modules which is still using + (through the generic-names package).

If this is not a bug I can try to get things changed in generic-names, but it would be good to at least get an understanding of why the change from + to \x00.

My expected behavior was that the class name hashes would be identical, for the same localIdentName ([folder]___[name]__[local]___[md4:contenthash:base64:5]).

Actual Behavior

The hashes are not the same because the passed in content is different.

• For css-loader the content is: app/javascript/components/QuickAction/styles.module.scss\u0000mobile-only
• For babel-plugin-react-css-modules the content is: app/javascript/components/QuickAction/styles.module.scss+mobile-only

css-loader is generating the classes for the CSS code whereas babel-plugin-react-css-modules is generating the classes to be used in the React markup. The actual result is that nothing on the page is styled. 😄

Code

n/a

How Do We Reproduce?

There's quite a bit of setup needed to reproduce the error, but hopefully by pinpointing the change above, this isn't necessary.

[alexander-akait]

Sorry, it is not bug, we change our logic, please open an issue in babel-plugin-react-css-modules

If this is not a bug I can try to get things changed in generic-names, but it would be good to at least get an understanding of why the change from + to \x00.

Because you can use + character in filename, so you can have same hash for different classes in some cases, but you can't use \x00 in filenames