Can't examine variables in scala code in Eclipse

Question

When I debug a Scala application in eclipse I get a dialog with this message on start up: Unable to set breakpoints in Main due to missing line number artifacts.

When I try to examine variables I get this error in the expressions window: " [in Main [in [Working copy] Main.scala [in [in src [in Scala1]]]]] does not exist"

I've tried setting various debug level settings for the Scala compiler including "line" and the highest setting but it doesn't seem to make any difference. I was able to see the contents once after messing with settings but was unable to do again so am wondering if there is a bug to do with bad cached state somewhere.

I am using the Indigo service release of Eclipse with version 2.0.0v2_09 of the Scala plugin.

Answer 1

You should upgrade to the new version of the Scala IDE !

(Strictly) Prior to 3.0.0, the debugger was the Java debugger, with no particular Scala support. But ScalaIDE 3.0.0 shipped with a Scala Debugger that should alleviate the problems you mention, specifically well-positioned breakpoints. You can read the release notes of 3.0.0 describing the debugger.

You should even try the release candidate version of 3.0.1, it contains fixes for the debugger, specifically skipping breakpoints. Try it, and if any issues remain, you can engage the IDE team on the mailing list, or file an issue, or ask another SO question!