sass worker hangs on js compilation errors under certain circumstance

[JLHwung]

I come across webpack hanging on company building machine. After hours and hours I manage to craft a tiny example ( link ) and reproduce it on my mac as well as travis ( link ).

Travis errored due to timeout and it is expected to fail immediately.

When webpack throws js compilation errors, chances are node-sass just setup a worker to compile sass and this worker does not get closed while the webpack exits. Thue webpack is hang.

Related issues may be sass/node-sass#857 but I am not sure if it is same issue.

This issue may involve several teams and I hope we can work together to fix. Before we fix the issue

As noted by @crvv the following is invalid and does not work at all.
I also find a workaround for this specific hanging situation:-

UV_THREADPOOL_SIZE=1 webpack --config ./config.js

It will disable the asyncQueue of sass-loader. Use at your own risk.

[alexander-akait]

@JLHwung can you provide minimum reproducible test repo?

[JLHwung]

After hours and hours I manage to craft a tiny example ( link ) and reproduce it on my mac as well as travis ( link ).

@evilebottnawi The minimal example is https:/JLHwung/webpack-sass-worker-hang-example.

It shall be fixed by webpack/webpack#6193, yet any further explanation is also definitely welcome.

[JLHwung]

Closed since webpack/webpack#6193 is merged.