Introduce a deps and a setup macro

[shs96c]

This allows us to pull in dependencies that we may need to ensure that
rules_jvm_external functions. At present, we use this to make sure we
use rules_java for our own java targets.

[jin]

It looks like the @rules_java load requirement is put on hold, so I don't think it's necessary to introduce that to this project now: bazelbuild/bazel#8746 (comment)

We should still have the scaffolding, maybe we could use this PR to build Hasher and MergeJars from source, instead of relying on a deploy jar?

[shs96c]

I don’t see any harm in using those rules, but building from source would be good. Want me to do that in a follow up PR? I think we’ll need to have the maven_install in the repositories file.

…

Sent from my iPhone

On 14 Nov 2020, at 08:16, Jin ***@***.***> wrote:  It looks like the @rules_java load requirement is put on hold: bazelbuild/bazel#8746 (comment) We should still have the scaffolding, maybe we could use this PR to build Hasher and MergeJars from source, instead of relying on a deploy jar? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or unsubscribe.

[jin]

I'd prefer to add a load dependency if we don't need to, and it's not clear what the plan is for enforcing @rules_java. Certainly not happening in Bazel 4.0, from release notes.

We can add the scaffolding for deps and setup in this PR, and follow up with a PR to build those binaries from source.

[jin]

Discussion about loading rules_java on bazel-discuss today: https://groups.google.com/forum/?utm_medium=email&utm_source=footer#!msg/bazel-discuss/XNvpWcge4AE/dVPDrQDhBQAJ