Flagless multiplatform build support

[jschaf]

What version of rules_go are you using?

0.18.1

What version of Bazel are you using?

0.23.2-homebrew

Will the go rules support the platforms attribute described in https://bazel.build/roadmaps/configuration.html under "Flagless multiplatform builds"? If so, is the late 2019 estimate accurate?

[jayconrod]

This will be supported after the underlying Bazel features are implemented and exposed in Starlark. We'll migrate the goos, goarch, and other mode attributes to use this internally, since they're causing a lot of problems.

I don't have any target date for this at the moment, but it's one of the higher priority projects in rules_go.

[jschaf]

Thanks. If I understand correctly, this is blocked by bazelbuild/bazel#6519.

[jayconrod]

Yes, right.

I'll close this issue because there's nothing concrete to do right now, and the upstream design may change. We'll add whatever support is needed in rules_go once Bazel has this capability though.