Can't collect static files if don't have vendor's JavaScript source map files

[Michael]

If one is using 3rd party JavaScript library, its often a minified Javascript file, that quite likely it has a source map url in a comment at the end. However its very likely that one does not have this source map files for the vendor libraries (probably only the vendor uses them).

Django version 4 introduces a new features of adjusting the URLs of these source map urls. Unfortunately if one does not have these source maps, its generates an error and stops. This seems unncessary that one can't create a release due to an unused third party file.

Altohugh I think it should only print a warning, as dicussed below people feel its worthwhile to keep this breaking change that breaks third part packages. Can we at least make it only raise an error if settings.DEBUG == True. That way in production where the sourcemaps are used less, its okay.

Alternatively/Additionally, could there be a settings.SOURCEMAPE_EXCEPTION etc that allows one to turn off this new break change?

[Mariusz Felisiak]

As far as I'm aware, if you use 3rd-party libraries which have JavaScript source map references then you should also have them. A minified JavaScript file shouldn't contain source map references if map is not provided by the vendor. I hope that makes sense.

[Adam Johnson]

I agree with Mariusz. From Django's perspective, it's the same as having a CSS file that references a missing font. Both are missing references and potentially a mistake! Even if you left the source map line in, the browser devtools will request it and hit a 404, and show you an error.

If you don't want the source map, delete the source map reference from the vendored file.

However its very likely that one does not have this source map files for the vendor libraries (probably only the vendor uses them).

This is just a difference in approach/opinion. I use source maps everywhere and I know many developers do too.

[Michael]

I updated the original issue.

Could we please at least add a settings options to allow one to disable this new behaviour that breaks quite a few packages?

For example using django-json-widget, uses some javascript files. And contry to stated above, it does not come with the sourcemaps, and one can't collectstatic.

[Michael]

Replying to Mariusz Felisiak:

As far as I'm aware, if you use 3rd-party libraries which have JavaScript source map references then you should also have them. A minified JavaScript file shouldn't contain source map references if map is not provided by the vendor. I hope that makes sense.

Although this makes sense, and they "should", it does not mean that they do. One has no control over source of third party packages, which do often do not include the source maps, e.g. django-json-widget. This is a breaking change, see: ​https://github.com/jmrivas86/django-json-widget/issues/63