Set up CI job for Gerrit on Java 9

[davido]

//CC @cushon, @jart.

Bazel@HEAD and upcoming 0.10.0 release should support Java 9 out of the box. Gerrit@HEAD supports Java 9, well, almost, the only missing dependency is this rules_closure PR: [1].

Please add a job to Bazel CI to verify Gerrit on Java 9.

[1] bazelbuild/rules_closure#235

[philwo]

We'll look into this! Thanks.

[davido]

@philwo Thanks. It worth mention, though, that the last needed change is still pending for review: [1]. Also, only upcoming Bazel version, 0.11.0 supports Java 9 out of the box. Once it's merged, the command to build gerrit with Java 9 would be:

  $ bazel --host_javabase=/usr/lib64/jvm/java-9-openjdk test \
      --javacopt='--release 9' \
      --java_toolchain=@bazel_tools//tools/jdk:toolchain_jdk9 //...

• [1] https://gerrit-review.googlesource.com/#/c/gerrit/+/147234/

[davido]

@philwo

In light of this thread: [1] and given that building Gerrit Code Review on JDK9 ist broken (bazelbuild/bazel#5896) on most recent Bazel master and even in 17.0rc1, and that this breakage wasn't discovered yet, any progress here?

All is needed is to set up JDK9 on CI host, and set up CI build on Gerrit master and activate JDK9:

$ bazel test \
  --host_java_toolchain=@bazel_tools//tools/jdk:toolchain_java9 \
  --java_toolchain=@bazel_tools//tools/jdk:toolchain_jdk9 \
   //...

[1] https://groups.google.com/d/topic/bazel-discuss/1116GHzkNm0/discussion

[philwo]

@davido Thanks for the clear explanation.

I'm OOO next week and we have to do some work on CI and Bazel before we can get this done, so it'll be ~2-3 weeks before I can get to this.

[davido]

@philwo Thanks for the update.

[philwo]

Update: We now have Ubuntu 18.04 LTS machines with system JDK being OpenJDK 9 and 10.

You can test on these machines by using the "ubuntu1804_java9" and "ubuntu1804_java10" platform in presubmit.yml / postsubmit.yml.

[davido]

You can test on these machines by using the "ubuntu1804_java9" and "ubuntu1804_java10" platform in presubmit.yml / postsubmit.yml.

Sorry, It doesn't tell me anything. I'm not familiar with buildkite.com.

[philwo]

No problem and sorry for not explaining better. Basically, we have a config file for Gerrit here: https://github.com/bazelbuild/continuous-integration/blob/master/buildkite/pipelines/gerrit-postsubmit.yml

We can add an entry that tests however you'd like to test Gerrit with Java 9. With @lberki rolling changes back and forth, I'm not sure if the --host_java_toolchain / --java_toolchain flags still apply as you mentioned above, but otherwise this is how it would look like: #322

[davido]

@philwo Thanks. That's clear now. I think that @lberki is rolling back JDK10 embedded JDK and javac support on Bazel@HEAD, but the JDK9 should still work and supported in Gerrit@HEAD.

Thanks a lot for moving Bazel CI forward and supporting newer Java versions. That will assure that future breakages can be detected and track down earlier. Great job!

[philwo]

Fixed in the meantime.