[SPARK-7318] [STREAMING] DStream cleans objects that are not closures

I added a check in `ClosureCleaner#clean` to fail fast if this is detected in the future. tdas

Author: Andrew Or <andrew@databricks.com>

Closes #5860 from andrewor14/streaming-closure-cleaner and squashes the following commits:

8e971d7 [Andrew Or] Do not throw exception if object to clean is not closure
5ee4e25 [Andrew Or] Fix tests
eed3390 [Andrew Or] Merge branch 'master' of github.com:apache/spark into streaming-closure-cleaner
67eeff4 [Andrew Or] Add tests
a4fa768 [Andrew Or] Clean the closure, not the RDD

1 files changed, 2 insertions, 1 deletions

diff --git a/streaming/src/main/scala/org/apache/spark/streaming/dstream/DStream.scala b/streaming/src/main/scala/org/apache/spark/streaming/dstream/DStream.scala
index 83d41f5762..f1f8a70655 100644
--- a/streaming/src/main/scala/org/apache/spark/streaming/dstream/DStream.scala
+++ b/streaming/src/main/scala/org/apache/spark/streaming/dstream/DStream.scala
@@ -553,7 +553,8 @@ abstract class DStream[T: ClassTag] (
     // because the DStream is reachable from the outer object here, and because 
     // DStreams can't be serialized with closures, we can't proactively check 
     // it for serializability and so we pass the optional false to SparkContext.clean
-    transform((r: RDD[T], t: Time) => context.sparkContext.clean(transformFunc(r), false))
+    val cleanedF = context.sparkContext.clean(transformFunc, false)
+    transform((r: RDD[T], t: Time) => cleanedF(r))
   }
 
   /**