LIVY-313. Fixed SparkRInterpreter always returning success.

[jonalter]

• Stopped redirecting stderr to stdout.
• Continue to read ErrorStream (it was only being read once).
• Checking for any errors returned by stderr before returning success.

LIVY-313

[alex-the-man]

Mind if you fix the style issue?

[alex-the-man]

There used to be a race condition in the code I fixed in #251. To solve it, I modified the code to redirect stderr to stdout so SparkRInterpreter doesn't need to read from multiple streams. To repo the issue, run this unit test in a loop.

I think this fix undoes my fix.

[jonalter]

@alex-the-man thanks for the feedback. Could you tell me how you run a single test or single test suite? I have been doing it by building my own class path and running org.scalatest.tools.Runner manually. I imagine there has to be an easier way to do it.

[alex-the-man]

@jonalter Do you use ideaj?

[jonalter]

@alex-the-man yes I do, but I am pretty new to using it.

[alex-the-man]

You can start a specific scalatest test case using the test runner integrated in IntelliJ. You will hit some errors if your environment variables are not set properly. You can set them referencing to pom.xml.

However, for your particular case, you can just add a infinite loop around this block. Let it run overnight to verify the race condition is gone.

[codecov-io]

Codecov Report

Merging #307 into master will increase coverage by 0.01%.
The diff coverage is 81.48%.

@@             Coverage Diff              @@
##             master     #307      +/-   ##
============================================
+ Coverage     70.35%   70.37%   +0.01%     
+ Complexity      689      688       -1     
============================================
  Files            94       94              
  Lines          4912     4925      +13     
  Branches        740      743       +3     
============================================
+ Hits           3456     3466      +10     
- Misses          954      955       +1     
- Partials        502      504       +2

Impacted Files	Coverage Δ	Complexity Δ
...ala/com/cloudera/livy/repl/SparkRInterpreter.scala	66.01% <81.48%> (+1.72%)	3 <0> (+1)	⬆️
...n/java/com/cloudera/livy/rsc/driver/RSCDriver.java	76.29% <0%> (-1.3%)	39% <0%> (-2%)
...cloudera/livy/repl/StatementProgressListener.scala	66% <0%> (+2%)	0% <0%> (ø)	⬇️
...la/com/cloudera/livy/scalaapi/ScalaJobHandle.scala	55.88% <0%> (+2.94%)	0% <0%> (ø)	⬇️

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[jonalter]

@alex-the-man, thanks for the info!

[jonalter]

I ran that one test overnight like you suggested with no failure.

[jonalter]

PR ready for review

[alex-the-man]

LGTM. @zjffdu

[zjffdu]

LGTM, thanks @jonalter will merge it.