boost_build with local boost submodule

[traceon]

(Bazel beginner here) Is it possible to use boost_build with a local boost source tree snapshot/git submodule instead of downloading it, i.e, when I have it under third_party/boost?

[UebelAndre]

Yeah, I don't see why not. Can you a bit more about what you're looking to do with build_boost? Maybe an example build file?

[traceon]

Don't really have any example, just want to be able to build my boost sources snapshot, and be able to link in [some] boost libs, built this way, into my other targets. Was hoping to get a minimal example here, actually.

[UebelAndre]

We're definitely looking into ways to have better examples. Does #474 help you out at all?

[jsharpe]

I would recommend looking towards https://github.com/nelhage/rules_boost first as this will build the libraries in isolation. You can override the included version of boost sources by defining a local_repository from your snapshot before calling the boost_deps macro.

[traceon]

@jsharpe thanks, I'll definitely give it a try! The work done there deserves respect. However, it seems to me that this approach will require constant maintenance with each boost upgrade, at least theoretically.

@UebelAndre the existing example works just fine, but downloads the archive with sources by default. What I haven't figured out is how to use a folder instead.

[UebelAndre]

You should hop in the Bazel Slack Channel to get quicker feedback and more helpful eyes.

In general though. You can setup a .bazelignore file in your top level workspace and use local_repository to create the repository you care about. Similar to what's happening in this repo with the examples. .bazelignore and top level WORKSPACE file

[traceon]

You should hop in the Bazel Slack Channel to get quicker feedback and more helpful eyes.

Got this:

Don’t have an @google.com email address?
Contact the workspace administrator at Bazel for an invitation.

Who should I contact, do you know?

[UebelAndre]

Hmm, I thought it was public
👋 Let’s move this to Slack! We’ve got 2588 folks from the team there already. You can sign up here: link

[traceon]

In general though. You can setup a .bazelignore file in your top level workspace and use local_repository to create the repository you care about. Similar to what's happening in this repo with the examples. .bazelignore and top level WORKSPACE file

With WORKSPACE:

...
local_repository(
    name = "boost",
    path = "third_party/boost",
)
...

...and third_party/BUILD.bazel:

...
load("@rules_foreign_cc//tools/build_defs:boost_build.bzl", "boost_build")
boost_build(
    name = "boost",
    lib_source = "@boost//:all"
)
...

If I put third_party in .bazelignore, and run bazel build //third_party:boost, I get:

ERROR: Skipping '//third_party:boost': no such package 'third_party': Package is considered deleted due to --deleted_packages

...and if I put third_party/boost in .bazelignore, and run bazel build //third_party:boost, I get:

ERROR: /path/third_party/BUILD.bazel:5:12: //third_party:boost depends on @boost//:all in repository @boost which failed to fetch. no such package '@boost//': No WORKSPACE file found in /private/var/tmp/_bazel_path/da18835db896305bb46480859a6b605c/external/boost

[UebelAndre]

You would build @boost//... or something. But try the slack link

[traceon]

Joined the slack, asked in #cc. Thanks!

[UebelAndre]

Gonna close this for now then. Happy slacking 😄

[traceon]

@jsharpe nelhage/rules_boost#9 has the same issue, however, there, it is kind of justified, since the source structure is hardcoded in the scripts.

[sunstarchan]

You would build @boost//... or something. But try the slack link

Hmm, I thought it was public
👋 Let’s move this to Slack! We’ve got 2588 folks from the team there already. You can sign up here: link

Could you invite me to the Bazel Slack channel?