[ZEPPELIN-2606] Fix compilation with R interpreter enabled

[andreaTP]

What is this PR for?

mvn -DskipTests clean package -Pr fails

What type of PR is it?

Bug Fix

What is the Jira issue?

[ZEPPELIN-2606]

How should this be tested?

mvn -DskipTests clean package -Pr

[zjffdu]

LGTM, but one concern is that why this bug is not found in CI, maybe we miss something in travis

[andreaTP]

yes a full compilation with all interpreters available should be included in CI build IMO ....

[khalidhuseynov]

LGTM

[zjffdu]

I think r is missing in INTERPRETERS of .travis.yml

[andreaTP]

INTERPRETERS is surprisingly an exclusion list @zjffdu https://github.com/apache/zeppelin/blob/master/.travis.yml#L40

[zjffdu]

@andreaTP That's is intended. It would be converted to be inclusive.

MODULES="-pl $(echo .,zeppelin-interpreter,${INTERPRETERS} | sed 's/!//g')"

[andreaTP]

good point, so I added it to the list, I think it fits the scope of this PR (let see what travis says)

[andreaTP]

Since R is under spark we need to enable it differently AFAICS
now it is enabled at least in one test (where all other interpreters are compiled).
Travis is happy I close and re-open this.

[jongyoul]

I have general question. Does -Pr works at the latest spark distribution?

[jongyoul]

ping

[necosta]

Q: Does -Pr works at the latest spark distribution?
A: Not sure. It works with 2.0.2. I haven't tried to compile it against 2.1.1. Any specific error you are getting?

[jongyoul]

Thanks, I just wonder if it works becase it was developed when spark was 1.5. One more question. Did you test -sparkR ? If you did, can you compare which one is proper for you? We had two different implementations and it's a bit hard to maintain it.

[necosta]

I'm no expert so don't trust my answer. I have both enabled and working, %r and %spark.r. The way I understand it, %r is just an interpreter to allow coding in R (as you would do in RStudio). And %spark.r is R + Spark, so you are able to interface with Spark in R as you would in Python or Scala. Which one to use?
depends on your use case I guess.

[necosta]

LGTM

[andreaTP]

do this need anything else to be merged?

[khalidhuseynov]

will be merging into master if no more discussion