How do you do develop an SBT project, itself?

Question

Background: I've got a Play 2.0 project, and I am trying to add something to do aspectj weaving using aspects in a jar on some of my classes (Java). (sbt-aspectj doesn't seem to do it, or I can't see how). So I need to add a custom task, and have it depend on compile. I've sort of figured out the dependency part. However, because I don't know exactly what I'm doing, yet, I want to develop this using the IDE (I'm using Scala-IDE). Since sbt projects (and therefore Play projects) are recursively defined, I assumed I could:

Add the eclipse plugin to the myplay/project/project/plugins.sbt
Add the sbt main jar (and aspectj jar) to myplay/project/project/build.sbt:

libraryDependencies ++= Seq( "org.scala-sbt" % "main" % "0.12.2", "aspectj" % "aspectj-tools" % "1.0.6" )
Drop into the myplay/project
Run sbt, run the eclipse task, then import the project into eclipse as a separate project.

I can do this, though the build.scala (and other scala files) aren't initially considered source, and I have to fiddle with the build path a bit. However, even though I've got the sbt main defined for the project, both eclipse IDE and the compile task give errors:

> compile
[error] .../myplay/project/Build.scala:2: not found: object keys
[error] import keys.Keys._
[error]        ^
[error] .../myplay/project/SbtAspectJ.scala:2: object Configurations is not a member of package sbt
[error] import sbt.Configurations.Compile
[error]            ^
[error] .../myplay/project/SbtAspectJ.scala:3: object Keys is not a member of package sbt
[error] import sbt.Keys._
[error]            ^
[error] three errors found

The eclipse project shows neither main nor aspectj-tools in its referenced-libraries. However, if I give it a bogus version (e.g. 0.12.4), reload fails, so it appears to be using the dependency.

So,... First: Is this the proper way to do this? Second: If so, why aren't the libs getting added. (Third: please don't let this be something dumb that I missed.)

Really, ANY pointers would be helpful. – mconner May 01 '13 at 03:43 — mconner, May 01 '13 at 03:43

score 7 · Answer 1 · answered Jun 26 '13 at 18:51

7

If you are getting the object Keys is not a member of package sbt error, then you should check that you are running sbt from the base directory, and not the /project directory.

answered Jun 26 '13 at 18:51

tmarthal

1,498
19
28

score 1 · Answer 2 · answered Sep 01 '13 at 04:42

sbt-aspectj

sbt-aspectj doesn't seem to do it, or I can't see how.

I think this is the real issue. There's a plugin already that does the work, so try making it work instead of fiddling with the build. Using plugins from build.scala is a bit tricky. Luckily there are sample projects on github:

import sbt._
import sbt.Keys._
import com.typesafe.sbt.SbtAspectj.{ Aspectj, aspectjSettings, compiledClasses }
import com.typesafe.sbt.SbtAspectj.AspectjKeys.{ binaries, compileOnly, inputs, lintProperties }


object SampleBuild extends Build {
  ....

  // precompiled aspects
  lazy val tracer = Project(
    "tracer",
    file("tracer"),
    settings = buildSettings ++ aspectjSettings ++ Seq(
      // stop after compiling the aspects (no weaving)
      compileOnly in Aspectj := true,

      // ignore warnings (we don't have the sample classes)
      lintProperties in Aspectj += "invalidAbsoluteTypeName = ignore",

      // replace regular products with compiled aspects
      products in Compile <<= products in Aspectj
    )
  )
}