v5.0 breaks Play Java apps when using pure Eclipse

[mkurz]

@benmccann you did release v5.0 a couple of days a ago which breaks Play projects when imported in pure Eclipse IDE (not ScalaIDE).

For reproduction:

• activator new myApp
• Chooseplay-java
• Add to project/plugins.sbt:

addSbtPlugin("com.typesafe.sbteclipse" % "sbteclipse-plugin" % "5.0.0")

• Add to build.sbt (like described in the Play docs here):

// Compile the project before generating Eclipse files, so that generated .scala or .class files for views and routes are present
EclipseKeys.preTasks := Seq(compile in Compile)
EclipseKeys.projectFlavor := EclipseProjectFlavor.Java           // Java project. Don't expect Scala IDE
EclipseKeys.createSrc := EclipseCreateSrc.ValueSet(EclipseCreateSrc.ManagedClasses, EclipseCreateSrc.ManagedResources)  // Use .class files instead of generated .scala files for views and routes

• Now run activator eclipse and afterwards import the project into Eclipse (I use latest Neon.1)

Result
You will get various errors that scala.* packages/classes can't be resolved.
That's because sbteclipse generates a .classpath file which tells the IDE to use a bundled Scala container - which actually is intended for ScalaIDE, Eclipse doesn't come with Scala.

Workaround
In build.sbt set

EclipseKeys.withBundledScalaContainers := false // Don't use scala bundle that comes with ScalaIDE

Now these lines from the "broken" .classpath file

  <classpathentry kind="con" path="org.scala-ide.sdt.launching.SCALA_CONTAINER"/>

become

  <classpathentry sourcepath="/home/mkurz/.ivy2/cache/org.scala-lang/scala-library/srcs/scala-library-2.11.8-sources.jar" kind="lib" path="/home/mkurz/.ivy2/cache/org.scala-lang/scala-library/jars/scala-library-2.11.8.jar">

This specific withBundledScalaContainers setting wasn't necessary in v4.0 and therefore also isn't documented in the Play docs.
For me it seems this line causes the problem.

@benmccann Should we update the Play docs (referenced above) to also include the withBundledScalaContainers := false setting or is this something which should be fixed in sbteclipse?

[benmccann]

Hmm, yeah, this sounds like a bug in sbteclipse where the default of withBundledScalaContainers is no longer being correctly set. Thanks for the detailed report

[benmccann]

5.0.1 released with the fix

[mkurz]

That was fast, thanks!