How to attach sources to SBT managed dependencies

Question

I'm using Scala IDE 2.0.1 and SBT 0.11.2 to start with Akka 2.0.1. My build.sbt looks like this:

name := "akka"

version := "0.1"

scalaVersion := "2.9.2"

resolvers += "Typesafe Repository" at "http://repo.typesafe.com/typesafe/releases/"

libraryDependencies += "com.typesafe.akka" % "akka-actor" % "2.0.1"

As you can see, there's nothing spectacular.

Now how can I tell Eclipse to use the artifact with the sources classifier for the akka-actor library?

In SBT, I can use update-classifiers to download sources and Javadocs to the Ivy repository, but even if I do this before running the eclipse command from the sbteclipse plugin then Eclipse still does not know the sources. Of course, I could do this manually, but this doesn't scale well for more libraries.

I have also tried to use the IvyDE plugin with the deliver-local command. While this integrates the dependency management, it doesn't seem to help with the sources.

Any clues?

Edit: This is the ivy.xml generated from deliver-local:

<?xml version="1.0" encoding="UTF-8"?>
<ivy-module version="2.0" xmlns:e="http://ant.apache.org/ivy/extra">
<info organisation="default" module="akka_2.9.2" revision="0.1" status="release" publication="20120506225613">
    <description>
    akka
    </description>
</info>
<configurations>
    <conf name="compile" visibility="public" description=""/>
    <conf name="runtime" visibility="public" description="" extends="compile"/>
    <conf name="test" visibility="public" description="" extends="runtime"/>
    <conf name="provided" visibility="public" description=""/>
    <conf name="optional" visibility="public" description=""/>
    <conf name="sources" visibility="public" description=""/>
    <conf name="docs" visibility="public" description=""/>
    <conf name="pom" visibility="public" description=""/>
</configurations>
<publications>
    <artifact name="akka_2.9.2" type="pom" ext="pom" conf="pom"/>
    <artifact name="akka_2.9.2" type="jar" ext="jar" conf="compile"/>
    <artifact name="akka_2.9.2" type="src" ext="jar" conf="sources" e:classifier="sources"/>
    <artifact name="akka_2.9.2" type="doc" ext="jar" conf="docs" e:classifier="javadoc"/>
</publications>
<dependencies>
    <dependency org="org.scala-lang" name="scala-library" rev="2.9.2" conf="compile->default(compile)"/>
    <dependency org="com.typesafe.akka" name="akka-actor" rev="2.0.1" conf="compile->default(compile)"/>
    <exclude org="org.scala-lang" module="scala-library" artifact="*" type="jar" ext="*" matcher="exact"/>
    <exclude org="org.scala-lang" module="scala-compiler" artifact="*" type="jar" ext="*" matcher="exact"/>
    <override org="org.scala-lang" module="scala-library" matcher="exact" rev="2.9.2"/>
    <override org="org.scala-lang" module="scala-compiler" matcher="exact" rev="2.9.2"/>
</dependencies>
</ivy-module>

I'm new to Ivy, so this doesn't tell me much. I just figure that it mentions sources and javadocs, but somehow the IvyDE doesn't pick it up.

Answer 1

I find that it's easier to give IvyDE and sbt different ivy cache directories. Yes, it takes more space, but sbt by default doesn't download sources. And once sbt has loaded the cache without sources, IvyDE won't add them. You can tell sbt to fetch them, but for me it's easier just to use more disk space and use two different caches.

I do this by leaving sbt at the default, and setting IvyDE to use this file in Preferences > Ivy > Settings tab > Ivy settings file:

<ivysettings>

    <settings defaultResolver="nexus" />

    <property
        name="nexus-public"
        value="http://localhost:8081/nexus/content/groups/public" />

    <resolvers>

        <ibiblio
            name="nexus"
            m2compatible="true"
            root="${nexus-public}" />
    </resolvers>

    <caches defaultCacheDir="${user.home}/.ivy2eclipse" />

</ivysettings>

That points to my local nexus server, so'll you'll need to modify it for your environment.

Answer 2

You can put

EclipseKeys.withSource := true

to your build.sbt, which lets sbteclipse download all sources and makes them accessible within Eclipse. Note, this will download all sources from all configured dependencies. I have no idea how to tell sbt to download only the sources for single dependencies.

Answer 3

I managed to get this working finally.

I had to use an external ivy settings file:

<ivysettings>
  <properties environment="env" />
  <settings defaultResolver="play" defaultResolveMode="dynamic" />
  <caches defaultCacheDir="${env.PLAY_HOME}/repository/cache" />
  <resolvers>
    <chain name="play">
      <ibiblio name="typesafe-releases" m2compatible="true" root="http://repo.typesafe.com/typesafe/releases" />
      <ibiblio name="sonatype-oss-releases" m2compatible="true" root="http://oss.sonatype.org/content/repositories/releases" />
      <filesystem name="local-filesystem">
        <ivy pattern="${env.PLAY_HOME}/repository/local/[organization]/[module]/[revision]/ivys/ivy.xml" />
        <artifact pattern="${env.PLAY_HOME}/repository/local/[organization]/[module]/[revision]/[type]s/[module](-[classifier]).[ext]" />
      </filesystem>
      <ibiblio name="central-uk" m2compatible="true" root="http://uk.maven.org/maven2" />
      <ibiblio name="typesafe-snapshots" m2compatible="true" root="http://repo.typesafe.com/typesafe/snapshots" />
      <ibiblio name="sonatype-oss-snapshots" m2compatible="true" root="http://oss.sonatype.org/content/repositories/snapshots" />
    </chain>
  </resolvers>
</ivysettings>

And add:

externalIvySettings(baseDirectory(_ / "ivysettings.xml"))

to my Build.scala.

The order of the resolvers in the chain proved to be important, because if Ivy finds a jar but no sources it won't check the other resolvers for sources/javadoc. The repository in the local Play install doesn't have sources or javadoc in.

This gets me source attachments for most of the jars in my dependencies when IvyDE resolves in Eclipse.

Answer 4

Finally I found a solution to let sbt download the sources and tell Eclipse where to find them.

Add in build.sbt:

EclipseKeys.withSource := true

Then run:

rm -rf  ~/.ivy2/cache/

sbt update-classifiers

sbt eclipse

The weird part is that if you already downloaded the dependencies in ivy, you have them in cache and you won't be able to download the sources for them.

Answer 5

Well, I have given up on this and returned to NetBeans 7.1.2 + Scala plugin + Maven. This combination is much better integrated and works out of the box without tinkering.