Handle paths for labels correctly

[jhnj]

In bazel the target @some_label is resolved as @some_label//:some_label.

When specifying replacements using this format, e.g.:

replacements:
  org.scala-lang.modules:
    scala-parser-combinators:
      lang: scala
      target:
        "@io_bazel_rules_scala_scala_parser_combinators"

the exports in the created BUILD file looks like @io_bazel_rules_scala_scala_parser_combinators//. This is not the same as @io_bazel_rules_scala_scala_parser_combinators and thus doesn't work.

This makes a target @some_label resolve to @some_label instead of @some_label// by:

• making the path of aLabel an empty list instead of a list containing an empty string if there is no path
• Adding a case to fromRoot for when the Label has no name and an empty path

Didn't find any direct tests for Label, should I add something / add a test somewhere else?

@johnynek

[johnynek]

sorry I lost track @jhnj

This is great.

[travisbrown]

Thanks for doing this, @jhnj!