sbt is using wrong scala version rather than using the configuration in build.sbt

Question

I have put these in the build.sbt file under current project's root directory

scalaHome := Some(file("/Users/ddam/scala-2.10.2"))

scalaVersion := "2.10.2"

And I ran sbt using

$ sbt --version
sbt launcher version 0.12.4

But still, I am seeing both the wrong version for sbt and scala when a particular dependency cannot be resolved

[warn]  Note: Some unresolved dependencies have extra attributes.  Check that these dependencies exist with the requested attributes.
[warn]      com.typesafe.sbteclipse:sbteclipse-plugin:2.4.0 (sbtVersion=0.12, scalaVersion=2.9.2)

Please help me.

Answer 1

It looks like sbteclipse requires SBT 0.13.0, and you are using version 0.12.4. You can specify the SBT version by following the directions on this page.

Some other notes: You probably want to use Scala 2.10.3, not 2.10.2.

Also, it's strange to specify scalaHome; usually SBT will automatically fetch the needed Scala jars for you. So to bootstrap a Scala environment, all you need to have installed are SBT and a JDK.

EDIT: (addressing comment below): When you build code with SBT, you may actually use two different versions of Scala. There is the version for SBT (what version of Scala the build system runs on), and the version for the code in your project (what version of Scala your code will run on).

The Scala version for SBT is determined by the SBT version you use. If you use 0.12.4, SBT will run on Scala 2.9.3. If you use 0.13.0, SBT will run on Scala 2.10.3. You control the SBT version by following these instructions.

To control the version of Scala your project will run on, you can set scalaVersion in <projectRoot>/build.sbt.

So, you're getting that error because you're using SBT 0.12.4, which uses Scala 2.9.3. SBT tries to find the sbteclipse plugin for 2.9.3, but it doesn't exist because it requires SBT 0.13.0 (=> Scala 2.10.3).