Webpack Warning in system_js_ng_module_factory_loader.js

[supermarcos]

I'm submitting a ... (check one with "x")

[x] bug report => search github for a similar issue or PR before submitting
[ ] feature request
[ ] support request => Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question

Current behavior
When compiling using webpack, in angular rc7 core libraries there are a couple of warnings.

Expected behavior
I guess no warnings... :-)

Reproduction of the problem
Install a bare project, the simplest you like using webpack with the Angular2 rc7 revision and you will get the warnings.

Please tell us about your environment:
All the last versions of Angular2 rc7, typings, ts and webpack related dependencies. All of them on the latest versions npm has.

• Angular version:
  2.0.0-rc.7

[supermarcos]

Is this happening to someone else?
Thanks!

[PatrickJS]

you need to provide context to Angular's use of System.import

      new webpack.ContextReplacementPlugin(
        // The (\\|\/) piece accounts for path separators in *nix and Windows
        /angular(\\|\/)core(\\|\/)(esm(\\|\/)src|src)(\\|\/)linker/,
        root('./src'), // location of your src
        {} // a map of your routes 
      ),

update:
the path changed to
/angular(\\|\/)core/
update:
#11580 (comment)

[supermarcos]

Thanks for your prompt answer, @gdi2290 , sorry if I am asking something stupid, but... where should I do that? Webpack config maybe? Thanks again!

[PatrickJS]

webpack.config.js

module.exports = {
  plugins: [
      new webpack.ContextReplacementPlugin(
        // The (\\|\/) piece accounts for path separators in *nix and Windows
        /angular(\\|\/)core/,
        root('./src'), // location of your src
        { }
      )
  ]
}
function root(__path) {
  return path.join(__dirname, __path);
}

or

new webpack.ContextReplacementPlugin(
  /angular(\\|\/)core/,
  path.resolve(__dirname, 'src'), // path to your src
  {}
)

update:
#11580 (comment)

[supermarcos]

Fantastic! Yep, that was the missing piece. Thank you very much!
Just one last question, why before with the RC6 I didn't get those warning and with the RC7 I do?
What is the actual purpose of that plugin?

Thank you very much for your help! You're a legend!

[robwormald]

i'm going to reopen this, as we're tracking what to do about it.

[Tragetaschen]

This bug doesn't yet mention the actual warning (it's only in the OP's image), so you cannot find it by searching:

WARNING in ./~/@angular/core/src/linker/system_js_ng_module_factory_loader.js
45:15 Critical dependency: the request of a dependency is an expression

[jtsom]

Except this error, for me, is happening in an Angular-cli app, while running tests with ng test.. there is no webpack config file...

[dcchristopher]

@jtsom Mind you, this is just a warning, not an error. However, like you, I was also getting that warning while at the same time getting some new errors in my karma tests (ng test). Like you, I have an app created with angular-cli. At first I thought the warning and the errors were related but undoing my recent changes disproved that theory. I had just recently added angular2-material and my unit tests were failing with errors like "template parse errors: md-whatever". I just had to update my unit tests (the beforeEach section in particular) and add all the referenced angular2-material providers and components used in each respective component class. I hope this helps you as well! The errors are definitely not very helpful and it took me longer than I care to admit to resolve this.