fix: remove sourceURL from emitted CSS

[alan-agius4]

This PR contains a:

• bugfix
• new feature
• code refactor
• test update
• typo fix
• metadata update

Motivation / Use-Case

In this case the sourceURL is not needed as the entire sourcemap which cotains all the information is being embeeded.

Multiple sourceURL is also causing issues when in Chrome devtools.

Additional Info

See: angular/angular-cli#24414 for more information.

[alexander-akait]

Can you create reproducible example using pure webpack, because I can't get two sourceURL

/*# sourceURL=webpack://./src/app/b/b.component.scss */
/*# sourceURL=webpack://./src/styles.scss */

[alan-agius4]

@alexander-akait all you need to do is enable sourcemaps in sass-loader.

Here's an example

master...alan-agius4:css-loader:repro#diff-b15393677601d8b57053e1e25f5e3e9ef695b570273563e83f2217315bf28cf1R2520-R2522

A sourceURL comment will be added for each file in the sass compilation.

[codecov]

Codecov Report

Base: 96.82% // Head: 96.81% // Decreases project coverage by -0.00% ⚠️

Coverage data is based on head (05c3699) compared to base (3f3f302).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1487      +/-   ##
==========================================
- Coverage   96.82%   96.81%   -0.01%     
==========================================
  Files          12       12              
  Lines        1133     1131       -2     
  Branches      412      411       -1     
==========================================
- Hits         1097     1095       -2     
  Misses         27       27              
  Partials        9        9              

Impacted Files	Coverage Δ
src/runtime/sourceMaps.js	100.00% <100.00%> (ø)

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[alexander-akait]

I am afraid it can break a logic for developer without sass-loader and less-loader (i.e. just pure CSS), why do not disable generation of sourceURL on sass-loader side?

[alexander-akait]

hm, maybe you are right, I looked at code and found we already built-in source map:

const data = `sourceMappingURL=data:application/json;charset=utf-8;base64,${base64}`;
const sourceMapping = `/*# ${data} */`;

and then duplicate:

const sourceURLs = cssMapping.sources.map(
  (source) => `/*# sourceURL=${cssMapping.sourceRoot || ""}${source} */`
);

Not sure why we are doing it, I want to look at github history and found why it was implemented

[alan-agius4]

Correct, I did look into the git history before doing the PR to see the reasoning behind this. But I didn’t find anything meaningful. It looks like it was implemented like this from the beginning.

[alexander-akait]

@alan-agius4 That is really strange, no one reports about it before 😃

[alexander-akait]

@alan-agius4 6da7e90, looks like it was implemented for angular 😄

[alexander-akait]

Okay, let's merge and release, I think it should not break the logic, because we really have the same in sourceMappingURL (maybe chrome had bugs with sources before, but I think we can't check)

[alan-agius4]

Thanks @alexander-akait