URLs are well structured and unique, with a sensible default - sourcing the file from the internet - and ubiquitous processes for easily mapping the URL to an alternative location.

I.e., when you're going to run the production build, the URLs are mapped to fetch from the vetted cache and not the internet.

I don't see any downsides to allowing them as a source, or making them the default approach

> and ubiquitous processes for easily mapping the URL to an alternative location.

This seems strange to me because the whole point of a Uniform Resource Locator is to specify where a resource can be located.

It's a bit like saying "My project depends on the binder on shelf 7 in Room 42, sixth binder from the left. Except when I go into production, then use...." Don't tell me what binder it's in, tell me what it is.

I can see a case made for URIs, which is basically what Java did.

This was a big annoyance for me back in the day when I was dealing with XML namespaces. URLs never made sense for that use case and too many tools tried to pull XSDs from the literal URL which was always generally out of date, some projects switch to URIs like tag uris or URNs and it was much better, imo.

From my experience, URNs really should be used more often for these sorts of things. One thing that AWS got right almost from the get go

Fully qualified domain names (java/maven) aren't URIs. The latter are far more transient. Maybe a form of permalink could work, but that likely places too great a burden on package maintainers. I don't see that working out honestly.

Isn’t that why GOPROXY exists though? Not sure why you would need an internet connection. URLs don’t necessarily equate to the internet. Our internal and external packages are all locally hosted and work regardless of the internet being available.

> By the time you're going to production, your vetted and locked dependency should be living in your own cache/mirror/vendored-repo/whatever so that you know exactly what code you built your project around and know exactly what the availability will be when you build/instantiate your project.

In the Go world this would be "vendored" dependencies, that is, the dependencies are within your source tree, and your CICD can build to its hearts content with no care in the world about the internet because it has the deps.

The URL is useful for determining which version of a specific project is being used - "Oh we switched to the one hosted on gitlab because the github one went stale"

The advantage of using gitlab, or github, or whatever public code repository is that you get to piggy back off their naming policies which ensure uniqueness.

But, at the same time, there's no reason that the repo being referred to cannot be in house (bob.local) or private.

Having said all of that, the Go module system is a massive improvement on what they did have originally (nothing) and the 3rd party attempts to solve the problem (dep, glide, and the prototype for modules, vgo), but it's not without its edge cases.

Isn't that just delegating the problem? URL dependencies do not replace what crates.io does, and a modern language will still want something like it. You'd just end up with most every dependency being declared as crates.io/foo.

URLs form a nice global namespacing system. But yes, I agree that it should be possible to actually get the source from anywhere.

Basically the URL of a package name should be primarily the ID, not the locator (even if it is used for location by default).

You can use the `replace` option in the Go mod file to redirect your dependency references elsewhere if you need to.

It worked for the rest of the Internet.

There is something to be said for separating {unique piece of content} and {hosted location}.

E.g. doi's https://en.m.wikipedia.org/wiki/Digital_object_identifier