Warning "Previous source map found, but options.sourceMap isn't set"

[Janaka-Steph]

Hello,

Despite all my efforts, I can't get rid of the postcss warning "Previous source map found, but options.sourceMap isn't set"
If I remove bootstrap-loader and all related things I don't have the warnings anymore.

Some packages I have:

babel-plugin-react-css-modules: 3.0.0
bootstrap: 4.0.0-alpha.6
bootstrap-loader: 2.1.0
node-sass: 4.5.3
postcss-loader: 2.0.6
postcss-scss: 1.0.1
precss: 1.4.0
sass-loader: 6.0.6
webpack: 2.6.1
webpack-dev-server: 2.5.0
My webpack.config.js : https://pastebin.com/QgLGNUbH
My webpack.bootsrap.config.js : https://pastebin.com/X9H0CTv6
My postcss.config.js : https://pastebin.com/a5grb2qx
My .bootstraprc : https://pastebin.com/NVq8Ne4J

The github repo : https://github.com/asseth/dao1901

I mention disableSassSourceMap: true in the .bootstraprc but it has no effect on the warnings.

Thank you for your help

[Justin Gordon]

@Janaka-Steph Please debug this a bit further. Thre could be something specific to the versions of the libraries you are using.

Sometimes it's best to just ignore some messages.

Please ask me to re-open this issue when you have more information.

[Janaka-Steph]

I don't see what more can I do.

[Benno]

I had the same and solved it by appending ?sourceMap to css, postcss and sass in the default Bootstrap 4 .bootstraprc:

styleLoaders:
  - style
  - css?sourceMap
  - postcss?sourceMap
  - sass?sourceMap

[Justin Gordon]

@b-zee, @Janaka-Steph can either of you submit a doc PR for this?

[SupinePandora43]

in postcss/postcss#1276 solved same issue but with stylus-loader
just set to all loaders (in rules e.g. css, css_modules) option sourceMap to true when NODE_ENV==="development".
when build set env var GENERATE_SOURCEMAP to false