dependsOn to instruct sbt to package dependent projects in multi-project build? - sbt

Question

I created a multi-project build in sbt. Here's build.sbt in the main directory:
lazy val root = project in file(".") aggregate(data, reco, result)
lazy val data = project dependsOn(common)
lazy val reco = project
lazy val result = project dependsOn(common)
lazy val common = project
When I use package or one-jar command, the classes and resources in common project are not packaged into data or result jars. So when I run the generated jar by
java -jar data_2.10-1.0-onejar.jar
it leads to NoClassDefFoundError as a consequence.
So could anyone help me deal with such problem? Thanks in advance.

Answer 1

Your dependent projects are not exporting Jars (producing classes only). Put the following line in the build.sbt of all dependent projects (including your current project too, if necessary):
exportJars := true
That should fix it.

Answer 2

I might be misunderstanding your issue...please pardon me if I have.
From Classpath dependencies:
A project may depend on code in another project. This is done by
adding a dependsOn method call.
and later (in the same doc):
Now code in core can use classes from util. This also creates an
ordering between the projects when compiling them; util must be
updated and compiled before core can be compiled.
and then in Per-configuration classpath dependencies:
foo dependsOn(bar) means that the compile configuration in foo depends
on the compile configuration in bar.
We may also need to see what package is all about:
> help package
Produces the main artifact, such as a binary jar. This is typically an alias for the task that actually does the packaging.
or even inspect it to see what dependencies it has:
> inspect package
[info] Task: java.io.File
[info] Description:
[info] Produces the main artifact, such as a binary jar. This is typically an alias for the task that actually does the packaging.
[info] Provided by:
[info] {file:/C:/dev/sandbox/0.13.2/}root-0-13-2/compile:package
[info] Defined at:
[info] (sbt.Defaults) Defaults.scala:565
[info] Dependencies:
[info] compile:packageBin
[info] Delegates:
[info] compile:package
[info] *:package
[info] {.}/compile:package
[info] {.}/*:package
[info] */compile:package
[info] */*:package
[info] Related:
[info] jacoco:package
[info] test:package
With all that said, package doesn't package other project's artifacts - you need the sbt-assembly plugin instead (as you're crossing the boundaries of a single project and most if not all tasks in sbt are single-project only).