I rebuilt yarnpkg 1.13 using webpack 4.7 from experimental and it worked fine. I manually tested the resulting package and its yarnpkg executable seems to work.
From visual inspection the webpack config that we are using seems compliant with the requirements of webpack 4: https://salsa.debian.org/js-team/node-yarnpkg/blob/master/debian/rules#L15 https://salsa.debian.org/js-team/node-yarnpkg/blob/master/scripts/build-webpack.js#L71 I would keep this bug open until the CI and users confirm that all work fine. Paolo
