Status of IntelliJ with Gradle

[Maximilian Michels <mx...@apache.org>]

Hi Beamers,

It's great to see the Beam build system overhauled. Thank you for all
the hard work.

That said, I've just started contributing to Beam again and I feel
really stupid for not having a fully-functional IDE. I've closely
followed the IntelliJ/Gradle instructions [1]. In the terminal
everything works fine.

First of all, I get warnings like the following and the build fails:

====
.../beam/sdks/java/core/src/main/java/org/apache/beam/sdk/package-info.java:29:
warning: [deprecation] NonNull in edu.umd.cs.findbugs.annotations has
been deprecated
@DefaultAnnotation(NonNull.class)
                   ^
error: warnings found and -Werror specified
1 error
89 warnings
=====

Somehow the "-Xlint:-deprecation" compiler flag does not get through but
"-Werror" does. I can get it to compile by removing the "-Werror" flag
from BeamModulePlugin but that's obviously not the solution.

Further, once the build succeeds I still have to add the relocated
Protobuf library manually because the one in "vendor" does not get
picked up. I've tried clearing caches / re-adding the project /
upgrading IntelliJ / changing Gradle configs.


Is this just me or do you also have similar problems? If so, I would
like to compile a list of possible fixes to help other contributors.


Thanks,
Max


Tested with
- IntelliJ 2018.1.6 and 2018.2.1.
- MacOS
- java version "1.8.0_112"

[1] https://beam.apache.org/contribute/intellij/