Produced URL is "undefined" rather than expected URL.

[Lattyware]

I have a bug that surfaced after updating css-loader, but is apparently a bug in extract-loader.

The issue:

After upgrading to 2.0.0 from 1.0.1, I am getting url(undefined) in my output CSS where I previously got a valid URL.

This seems to happen when the URL is referenced multiple times across imported files - after the first reference undefined is output.

• Operating System: Arch Linux
• Node Version: 11.3.0
• NPM Version: 6.4.1
• webpack Version: 4.27.1

Expected Behavior

The URL should be the same each time it is referenced.

Actual Behavior

undefined is output instead of the URL after the first reference.

Code

@import "./test2";

.test1 {
    background: url(../../assets/test.png);
}

.test2 {
    background: url(../../assets/test.png) repeat;
}

Produces:

.test2{background:url(d41d8cd98f00b204e9800998ecf8427e.png) repeat}.test1{background:url(undefined)}

How Do We Reproduce?

See the attached project.

And the response from the css-loader project - I assumed it was a problem on their end as it surfaced with the updated version, but apparently not:

Sorry not related to css-loader, problem in extract-loader, problem here https://github.com/peerigon/extract-loader/blob/master/src/extractLoader.js#L144, need rewrite logic, maybe use Object/Map (like { __EXTRACT_LOADER_PLACEHOLDER__000_000: 'asset.png' }) and get asset url based __EXTRACT_LOADER_PLACEHOLDER__000_000 index.

[yenshih]

Huge bug...
Any updates? May I take charge of this repo if it's currently unmaintained? @jhnns

[yenshih]

Still no response? :(

[klesun]

@yenshih, if you are capable of taking charge of this project, would you mind filing a Pull Request to fix this issue, please? You are our only hope apparently.

[yenshih]

I've forked a repo and published extract-text-loader. @klesun

[klesun]

Oh, cool, thanks, I guess this is it.

[geonanorch]

Thanks @yenshih , the new extract-text-loader fixed it for me.
I saw that there are new commits from @jhnns on extract-loader, so there is still hope that this issue gets fixed at the source and remove the need for a clone.