[ssmoot]

I must be misunderstanding the question. Aggregation of non-PLAY sbt projects has worked from day one of Play 2.0 AFAIK. (That's when I started using both, and we've had sbt projects as bit submodules compiled as dependencies from the start).

I even did a presentation with examples for my local Scala User Group: http://slid.es/samsmoot/some-sbt

[eropple]

Yeah, maybe we're talking about different things; I may be using the wrong sbt terminology because I generally try to avoid it. =) Here's the original bug where some WTFs were exchanged:

http://play.lighthouseapp.com/projects/82401/tickets/453-nee...

Ben's patch made the workaround less terrible for 2.1, but it's still a really weird hacky thing to me and I never got it working with my Maven projects (my preferred backend uses Dropwizard so using a sbt project wasn't really optimal at the time).

[ssmoot]

This ticket is (justifiably IMO) marked as invalid. It's not a bug, misfeature or anything. It looks like a misunderstanding honestly.

If you approach it with a "Play first" mindset and ignore that any of the Play build-cycle stuff only works because it's built on SBT it's going to be rough going.

An "SBT first" mindset makes it much easier.

Create three console apps in three different folders. Doesn't matter where on your system these live.

Now create a fourth directory, add a project sub-folder and a `Build.scala`. Aggregate the projects together and make Project-C a dependency of Projects A and B. A and B are otherwise completely unrelated.

Now when you drop into the SBT console you can run test, compile, etc. All your standard aggregation tasks. If you wanted to actually run A or B, you can run the `run` task and it'll ask you what main-class to execute.

Here's the only real difference as far as Play is concerned: It doesn't use the standard SBT `run` task. So to get the `run` task from the Play plugin you first need to select your Play sub-project: `project my-play-project`. Now you can run `run` and it'll work like a normal Play application.

I think that extra step is actually resolved in Play 2.2 (it uses the standard `run` task now I've heard).

In this setup your "root project" isn't your Play app. It's a code-less project just defining the build and dependencies between your projects. You could add your common project to the Play app's Build.scala, and use `file()` in the Project declaration for it. The project can live anywhere. It's not at all necessary it be in a sub-path, use symlinks, anything like that.

In SBT 0.13 it's even better since you can do almost everything in .sbt files, which unlike a Build.scala can be built up across several projects. So Play-App-A can read the build.sbt from ../common/build.sbt and use that. Where a Build.scala has to be all-encompasing, so your common project configuration would have to reside in my-play-project-a/project/Build.scala.

SBT really is very nice. :-) I've used Maven, Bundler, Buildr, etc. Written my own JRuby Maven+Rubygems build tool (http://github.com/sam/doubleshot). The docs for SBT are real heavy, but if you set aside a few hours to watch some presentations on Parleys, Youtube, etc, it's pretty easy to get into.

Feel free to ping me if you're interested and could use a hand.