Empty string is rewritten as './' in urlToRequest

[darrenscerri]

Related issue: webpack-contrib/css-loader#463

Calling urlToRequest with an empty string resolves to ./. This behaviour should not be allowed, or rather keep as an empty string and let Webpack handle it.

[jhnns]

Mhmm, I think the current behavior is correct. CSS does not distinguish between url('file.jpg') and url('./file.jpg'). That's why an empty string '' should be equivalent to './'. Could you describe your use-case? Why do you have an empty url() statement—and how is webpack supposed to handle an empty request?

[jhnns]

Ah ok ... this was an error in the first place. What error does webpack report in this case?

[darrenscerri]

Webpack doesn't report any errors but proceeds to trying to require './ even if it's a JS file.

The original issue was here: facebook/create-react-app#1875. The url('') was a mistake but lead to a very hard-to-find bug.

Webpack currently warns if somebody does a require('') (webpack/webpack#2006).

Maybe we should warn if somebody tries to rewrite ''?

[jhnns]

Yeah, I totally see that. While transforming '' to './' is theoretically correct, it is most likely an error.

I thought about throwing an error if an empty url is passed, but that wouldn't be very pleasant to use and it would be a breaking change since the call needs to be wrapped in try/catch.

Maybe it's best to just keep it as it is and let webpack handle it correctly (as you suggested)... not the most beautiful solution 😞, but it would probably work.

[jhnns]

@darrenscerri Would you be up to a pull-request? Should be a small change...

[darrenscerri]

@jhnns Added pull-request