[SPARK-14889][Spark Core] scala.MatchError: NONE (of class scala.Enumeration) when spark.scheduler.mode=NONE

[sbcd90]

What changes were proposed in this pull request?

Handling exception for the below mentioned issue

➜  spark git:(master) ✗ ./bin/spark-shell -c spark.scheduler.mode=NONE
16/04/25 09:15:00 ERROR SparkContext: Error initializing SparkContext.
scala.MatchError: NONE (of class scala.Enumeration$Val)
    at org.apache.spark.scheduler.Pool.<init>(Pool.scala:53)
    at org.apache.spark.scheduler.TaskSchedulerImpl.initialize(TaskSchedulerImpl.scala:131)
    at org.apache.spark.SparkContext$.org$apache$spark$SparkContext$$createTaskScheduler(SparkContext.scala:2352)
    at org.apache.spark.SparkContext.<init>(SparkContext.scala:492)

The exception now looks like

java.lang.RuntimeException: The scheduler mode NONE is not supported by Spark.

How was this patch tested?

manual tests

[jaceklaskowski]

In TaskSchedulerImpl they use: "Unrecognized spark.scheduler.mode: $schedulingModeConf" so I'd change it to "Unsupported spark.scheduler.mode: $schedulingMode".

I'm also not sure about the other places like https://github.com/apache/spark/blob/master/core/src/main/scala/org/apache/spark/scheduler/TaskSchedulerImpl.scala#L133-L138. I know that the change would not let it be executed with NONE or unsupported scheduling modes, but when Pool changes...just thinking aloud.

[sbcd90]

Hi @jaceklaskowski ,

Thanks for your review. I think it is safe that we make the changes at both the places.
I also checked for the occurrence of scheduler mode & I feel it is sufficient to make the changes at these two places only.
I also corrected the exception message now.
Please have a look & comment now.

[srowen]

Use something like IllegalArgumentException

[sbcd90]

Hi @srowen ,

changed to IllegalArgumentException.

[rxin]

LGTM pending Jenkins.

[SparkQA]

Test build #2883 has finished for PR 12666 at commit 4658936.

• This patch fails to build.
• This patch merges cleanly.
• This patch adds no public classes.

[srowen]

Jenkins retest this please

[SparkQA]

Test build #56986 has finished for PR 12666 at commit 4658936.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[srowen]

Merged to master