Option to disable cache busting with sourceMap enabled

[Zizaco]

What problem does this feature solve?

I strongly believe that an option to disable cache busting for hot-reload would solve a problem that many are having.

In loader.js:81 the this.sourceMap always triggers the cache busting of filenames, even when trying to generate code-coverage. Where one would want to have:

• Precise filenames (without the "?[cache-key]" thing)
• An actual SourceMap

So, at the end, ironically, when source-map is enabled in webpack, vue-loader informs wrong filenames to code-coverage reports. For example:

/path/to/project/src/components/MyComponent.vue?7b4a5b1a
// instead of
/path/to/project/src/components/MyComponent.vue

Forcing people to do "workarounds" to get the real filename. For example:
https://github.com/mattlewis92/karma-coverage-istanbul-reporter/pull/3/files#diff-ff384da5c93b71dffa19fa30af8e2a2cR48

End user experience

Today the setup to get proper code-coverage of vue components is more complicated than it should.

With an option to disable cache busting in source-map filenames, code-coverage of .vue files would be as easy as $ nyc mocha-webpack test/**/*.spec.js with a reasonable simple webpack config (even without karma).

Evidence that this is a problem

There are many people struggling with this 😢 (my team included):

• https://stackoverflow.com/questions/42282102/error-output-with-karma-instanbul-coverage-reports
• https://stackoverflow.com/questions/44145417/nyc-istanbul-with-vue-vue-components
• https://github.com/mattlewis92/karma-coverage-istanbul-reporter/issues/2
• https://stackoverflow.com/questions/44454099/istanbul-instrumenter-loader-coverage-issues-dont-match-source
• Error: Unable to lookup source webpack-contrib/istanbul-instrumenter-loader#46
• https://forum.vuejs.org/t/question-about-code-coverage-with-istanbul/5270
• Problem with sourcemaps #620
  (and probably others)

What does the proposed API look like?

options: {
  cacheBusting: false // true by default (:
}
...

Because source-map !== cache busting for hot-reload 😅

[kriansa]

After trying to setup webpack and mocha with a similar setup, I have also faced this issue.

This makes the filename be set to a invalid name, making istanbul html output broken due the absence of the "file".

[kriansa]

In case anyone needs it, I've done the proposed changes here.

[infn8]

This is still happening for me. the issue I have is not coverage libraries like istanbul but just editing options in developer tools. Using css in js is great but with sourcemaps on, changing anything in devtools breaks the site because all the filenames become wrong.