This turns out to be really hard to do in practice. Generally speaking any time you use ExtractTextPlugin you get a ConcatSource which always has sourceAndMap available. The only case you don't get a source map is when another plugin generates a CSS file that uses RawSource or something similar. One such plugin is optimize-css-assets-webpack-plugin when you don't tell the CSS processor to generate a source map (e.g. cssProcessorOptions has no map entry).
Everything goes into ExtractTextPlugin and that ALWAYS generates something with a source map, even if it’s an empty one. The issue here is your css optimizer; it goes:
didi0613
commented
6 years ago
This turns out to be really hard to do in practice. Generally speaking any time you use
ExtractTextPluginyou get aConcatSourcewhich always hassourceAndMapavailable. The only case you don't get a source map is when another plugin generates a CSS file that usesRawSourceor something similar. One such plugin isoptimize-css-assets-webpack-pluginwhen you don't tell the CSS processor to generate a source map (e.g.cssProcessorOptionshas nomapentry).Everything goes into
ExtractTextPluginand that ALWAYS generates something with a source map, even if it’s an empty one. The issue here is your css optimizer; it goes:ExtractTextPlugin -> Optimizer -> SplitterAnd that kills everything.
Original PR from @didi0613 here: https://github.com/metalabdesign/css-split-webpack-plugin/pull/23 We just include a test in this one and a bit more of an investigation into why things happened the way they did.