Source map URLs shouldn't be prefixed with a local path

[japgolly]

Do you want to request a feature or report a bug?

Bug.

What is the current behavior?

Some libraries (i.e. nearly all created via Scala.JS) have URLs in their source maps. However when being used with webpack, webpack is prepending a ./ to all the URLs results in trillions of warnings like this:

[info] Cannot find source file 'https://raw.githubusercontent.com/scala/scala/v2.12.1/src/library/scala/collection/immutable/Vector.scala': Error: Can't resolve './https://raw.githubusercontent.com/scala/scala/v2.12.1/src/library/scala/collection/immutable/Vector.scala' in '/home/golly/projects/misc/target/scala-2.12/scalajs-bundler/main'
[info]  @ ./fastopt-launcher.js 1:0-91
[info] 
[info] WARNING in ./demo-fastopt.js
[info] Cannot find source file 'https://raw.githubusercontent.com/scala/scala/v2.12.1/src/library/scala/collection/immutable/List.scala': Error: Can't resolve './https://raw.githubusercontent.com/scala/scala/v2.12.1/src/library/scala/collection/immutable/List.scala' in '/home/golly/projects/misc/target/scala-2.12/scalajs-bundler/main'
[info]  @ ./fastopt-launcher.js 1:0-91
[info] 
[info] WARNING in ./demo-fastopt.js
[info] Cannot find source file 'https://raw.githubusercontent.com/scala/scala/v2.12.1/src/library/scala/collection/immutable/Stream.scala': Error: Can't resolve './https://raw.githubusercontent.com/scala/scala/v2.12.1/src/library/scala/collection/immutable/Stream.scala' in '/home/golly/projects/misc/target/scala-2.12/scalajs-bundler/main'
[info]  @ ./fastopt-launcher.js 1:0-91
[info] 
[info] WARNING in ./demo-fastopt.js
[info] Cannot find source file 'https://raw.githubusercontent.com/scala/scala/v2.12.1/src/library/scala/collection/immutable/StringOps.scala': Error: Can't resolve './https://raw.githubusercontent.com/scala/scala/v2.12.1/src/library/scala/collection/immutable/StringOps.scala' in '/home/golly/projects/misc/target/scala-2.12/scalajs-bundler/main'
[info]  @ ./fastopt-launcher.js 1:0-91
[info] 
[info] WARNING in ./demo-fastopt.js
[info] Cannot find source file 'https://raw.githubusercontent.com/scala/scala/v2.12.1/src/library/scala/collection/immutable/WrappedString.scala': Error: Can't resolve './https://raw.githubusercontent.com/scala/scala/v2.12.1/src/library/scala/collection/immutable/WrappedString.scala' in '/home/golly/projects/misc/target/scala-2.12/scalajs-bundler/main'
[info]  @ ./fastopt-launcher.js 1:0-91

And resulting in a final source map that no longer works for those libraries.

If the current behavior is a bug, please provide the steps to reproduce.

Setup any dummy project with Scala.JS and scalajs-bundler which runs everything through webpack.

What is the expected behavior?

Source map links that can be identified as absolute URLs should be used as is, without modification.

I believe the fix would be a very simple test like this before prepending:
https://github.com/jantimon/html-webpack-plugin/pull/619/files

Please mention other relevant information such as the browser version, Node.js version, webpack version and Operating System.

Using webpack 2.2.1, Node.JS 7.7.3.

[sokra]

I wonder where this message origin in Cannot find source file ...

Could you run it with --display-error-details (errorDetails: true in stats)?

[japgolly]

Hi @sokra, I tried with errorDetails: true and the output was the same as before. I set stats: "verbose" and still didn't get any additional, useful info (snippet below). I also set stats: "none" to confirm my settings we being detected and they were.

[info] WARNING in ./demo-fastopt.js
[info] Cannot find source file 'https://raw.githubusercontent.com/japgolly/scalajs-react/v1.0.0-RC1/core/src/main/scala/japgolly/scalajs/react/CtorType.scala': Error: Can't resolve './https://raw.githubusercontent.com/japgolly/scalajs-react/v1.0.0-RC1/core/src/main/scala/japgolly/scalajs/react/CtorType.scala' in '/home/golly/projects/misc/target/scala-2.12/scalajs-bundler/main'
[info]  @ ./fastopt-launcher.js 1:0-91
[info] 
[info] WARNING in ./demo-fastopt.js
[info] Cannot find source file 'https://raw.githubusercontent.com/japgolly/scalajs-react/v1.0.0-RC1/core/src/main/scala/japgolly/scalajs/react/Callback.scala': Error: Can't resolve './https://raw.githubusercontent.com/japgolly/scalajs-react/v1.0.0-RC1/core/src/main/scala/japgolly/scalajs/react/Callback.scala' in '/home/golly/projects/misc/target/scala-2.12/scalajs-bundler/main'
[info]  @ ./fastopt-launcher.js 1:0-91
[info] 
[info] WARNING in ./demo-fastopt.js
[info] Cannot find source file 'https://raw.githubusercontent.com/japgolly/scalajs-react/v1.0.0-RC1/core/src/main/scala/japgolly/scalajs/react/package.scala': Error: Can't resolve './https://raw.githubusercontent.com/japgolly/scalajs-react/v1.0.0-RC1/core/src/main/scala/japgolly/scalajs/react/package.scala' in '/home/golly/projects/misc/target/scala-2.12/scalajs-bundler/main'
[info]  @ ./fastopt-launcher.js 1:0-91
[info] 
[info] WARNING in ./demo-fastopt.js
[info] Cannot find source file 'https://raw.githubusercontent.com/japgolly/scalajs-react/v1.0.0-RC1/core/src/main/scala/japgolly/scalajs/react/component/ScalaBuilder.scala': Error: Can't resolve './https://raw.githubusercontent.com/japgolly/scalajs-react/v1.0.0-RC1/core/src/main/scala/japgolly/scalajs/react/component/ScalaBuilder.scala' in '/home/golly/projects/misc/target/scala-2.12/scalajs-bundler/main'
[info]  @ ./fastopt-launcher.js 1:0-91
[info] 
[info] WARNING in ./demo-fastopt.js

[japgolly]

Cannot find source file seems to be coming from here:
https://github.com/webpack-contrib/source-map-loader/blob/v0.2.0/index.js#L65

I'm not too worried about that though because it just seems to be wrapping the underlying error which is:

Error: Can't resolve './https://raw.githubusercontent.com/japgolly/scalajs-react/v1.0.0-RC1/core/src/main/scala/japgolly/scalajs/react/CtorType.scala' in '/home/golly/projects/misc/target/scala-2.12/scalajs-bundler/main'

I submitted a PR to loader-utils to stop the prefixing, that's where that was happening:
webpack/loader-utils#79

Unfortunately I'm still getting the same errors, just the prefix has been correctly removed:

Error: Can't resolve 'https://raw.githubusercontent.com/japgolly/scalajs-react/v1.0.0-RC1/core/src/main/scala/japgolly/scalajs/react/internal/Semigroup.scala' in '/home/golly/projects/misc/target/scala-2.12/scalajs-bundler/main'
 @ ./target/scala-2.12/scalajs-bundler/main/fastopt-launcher.js 1:0-91

[jhnns]

Looks like scalajs-bundler is using the source-map-loader. The source-map-loader uses webpack's resolver to resolve the source-map. webpack's resolver, however, cannot resolve remote resources via http and such.

So, why are they using the source-map-loader at all?

And: I'm also not sure if it's a good idea to point the sourceMappingURL to raw.githubusercontent.com...

[julienrf]

So, why are they using the source-map-loader at all?

We use source-map-loader to preserve (as most as possible) source-map continuity across libraries.

[nartamonov]

Any update on this, guys?

[alexander-akait]

@webpack-bot move to webpack-contrib/source-map-loader

[webpack-bot]

I've moved it to webpack-contrib/source-map-loader.