source-map-loader overrides alias setting in webpack config, causing multiple inclusions of a library

[seansfkelley]

The repro for this bug is a little involved, so I made a repo for it: https://github.com/seansfkelley/source-map-loader-bug

Summay: if you want to do local development across multiple repos but have a singleton specified in the webpack config's alias block (real world example: React, which generally has to be a singleton on the page), and the root one uses source-map-loader, it will override the alias config and include the versions of the library that are installed locally to the target of the link.

[seansfkelley]

Turns out this is an issue with Webpack itself, not this particular loader. Closing in favor of webpack/webpack#2441.