I'm aware of this, but I don't think it is happening on the sbt side. It could be by design for Ivy, but I've not seen anything in the Ivy documentation that indicates why it gets dropped.
-Mark
> Hm. The old coffee-script plugin seemed to download it okay without you
> having to add the dependency explicitly in your own build.
I just tried it and it failed for me. If you look at the published pom, the URL information is not there.
Ivy uses the URL as a hint for where to get a file when it can't find it in any repositories, so perhaps it caches that information for use in general once you've built coffee-script directly (where it would see the URL declared).
> I updated the ivy.xml in my downloaded plugin (in ~/.ivy2) to include the
> artifact with the URL, and SBT then worked fine.
In theory, you could modify the delivered XML file, but it would probably be better to fix it in Ivy properly.
-Mark