Macro hygiene problem with macros from external workspace

[iain.m...@gmail.com]

Hi all,

I've run into what seems like a slightly awkward macro hygiene problem.

What I want to do is:
- Workspace A defines a tool, and a macro for calling that tool (i.e. wrapping a genrule)
- Workspace B imports and uses that macro

But the macro is evaluated in the context of workspace B, so I don't see how it can unambiguously refer to the tool which lives in workspace A. It needs to use e.g. "@A//tools/macro.bzl", but how do I know my workspace is going to be imported as @A? Workspace B might want to import it under a different name, to resolve a namespace conflict.

Here's my specific example: https://github.com/iainmerrick/ink/commit/153b75808933883cd601494c2db64d79e8a999d9

Iain

[László Csomor]

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[Kristina Chodorow]

It's not required, but every WORKSPACE file should start with a line:

workspace(name = "A")

(or "B", or whatever you want the global name of that workspace to be).  We're encouraging people to use Java package-like names (e.g., Bazel's workspace name is io_bazel).  Bazel gives you an annoying warning if you try to import a repository using the wrong name (e.g., if you wrote http_archive(name = "com_bazel", ...) for importing io_bazel).  

See https://www.bazel.io/versions/master/docs/be/functions.html#workspace for more info.

[Iain Merrick]

Aha, that'll do it, thanks!

The docs are fantastic overall, but they're a little bit light on explaining the best practices for publishing a repository for other people to use. The info is there but you have to hop around a lot. (This isn't unique to Bazel, other build systems tend have the same documentation gap.)

[Iain Merrick]

Just figured out a specific problem -- the workspace() function isn't mentioned on the "Workspace Rules" page: https://www.bazel.io/versions/master/docs/be/workspace.html