Just a note - there was a fix in branch-1.0 (and Spark 1.0.1) that introduced a new bug worse than the original one.
https://issues.apache.org/jira/browse/SPARK-1199 The original bug was an issue with case classes defined in the repl. The fix caused a separate bug which broke most compound statements in the repl (val x = 1; val y = x + 1). I've reverted the original SPARK-1199 fix in the 1.0 branch. Since repl changes are some of the riskier ones in Spark, I'm planning to leave this fix out of 1.0.X entirely. The final, correct fix for this will appear in Spark 1.1. - Patrick