[llvm-dev] Pre-commit CI with libc++

[Louis Dionne via llvm-dev]

> On Nov 24, 2020, at 14:17, Tom Stellard <tstellar at redhat.com> wrote:
> 
> On 11/24/20 10:29 AM, Louis Dionne via llvm-dev wrote:
>> Folks,
>> I am pleased to announce the move of libc++ to pre-commit CI. Over the past few months, we have set up Buildkite jobs on top of the Phabricator integration built by Mikhail and Christian, and we now run almost all of the libc++ build bots whenever a Phabricator review is created. The bots also run when a commit is pushed to the master branch, similarly to the existing Buildbot setup. You can see the libc++ pipeline in action here: https://buildkite.com/llvm-project/libcxx-ci.
>> This is great -- we’ve been waiting to set up pre-commit CI for a long time, and we’ve seen a giant productivity gain since it’s up. I think everyone who contributes to libc++ greatly benefits, seeing how reviews are now used to trigger CI and improve our confidence in changes.
>> This change does have an impact on existing build bots that are not owned by one of the libc++ maintainers. While I transferred the build bots that we owned (which Eric had set up) to Buildkite, the remaining build bots will have to be moved to Buildkite by their respective owners. These builds bots are (owners in CC):
>>     libcxx-libcxxabi-x86_64-linux-debian
>>     libcxx-libcxxabi-x86_64-linux-debian-noexceptions
>>     libcxx-libcxxabi-libunwind-x86_64-linux-debian
>>     libcxx-libcxxabi-singlethreaded-x86_64-linux-debian
>>     libcxx-libcxxabi-libunwind-armv7-linux
>>     libcxx-libcxxabi-libunwind-armv8-linux
>>     libcxx-libcxxabi-libunwind-armv7-linux-noexceptions
>>     libcxx-libcxxabi-libunwind-armv8-linux-noexceptions
>>     libcxx-libcxxabi-libunwind-aarch64-linux
>>     libcxx-libcxxabi-libunwind-aarch64-linux-noexceptions
>> The process of moving these bots over to Buildkite is really easy. Please take a look at the documentation at https://libcxx.llvm.org/docs/AddingNewCIJobs.html#addingnewcijobs and contact me if you need additional help.
>> To make sure we get the full benefits of pre-commit CI soon, I would like to put a cutoff date on supporting the old libc++ builders at http://lab.llvm.org:8011/builders. I would propose that after January 1st 2021 (approx. 1 month from now), the libc++ specific build bots at lab.llvm.org <http://lab.llvm.org>be removed in favor of the Buildkite ones. If you currently own a bot, please make sure to add an equivalent Buildkite bot by that cutoff date to make sure your configuration is still supported, or let me know if you need an extension.
> 
> Does this mean there will no longer be post-commit CI for libcxx?

No. Like I said above, the main branch gets built as well when we commit to libc++, like the current Buildbots. The emailing of committers is still a work in progress, though, but I monitor the pipeline regularly.

Louis