I've stated it before here (and elsewhere). Email-based workflows are fine except with the metadata tracking side. As a contributor, it is very hard to know:

- who has looked at your patch
- who plans to look at your patch
- once accepted, where it got merged to
- when that merge will make it into a release
- CI status

As a reviewer it is hard to know:

- is this the latest revision
- is the author working on changes out-of-band

*Some* kind of central depot is, IMO, essential for wrangling all the work that goes into a project (or subsystem for Linux since any single central depot would likely end up like LKML: too noisy to be generally useful by non-bots due to heavy filtering). Not everyone has their finely tuned email workflows or the time to set them up for one-off patch submissions.

I'm happy to see progress in this area. Some notes on the actual implementation here:

> And buildbot itself is automated, so whenever a change is made to add a new builder, or define a new container, the buildbot automatically reconfigures itself and the workers will start using the new container images starting with the next build.

This makes historical builds hard because "how was commit X tested" has some out-of-band information. I've come to storing Dockerfiles for CI in the repo itself and using dates for the image tags (macOS and Windows setups require some out-of-band info, but we minimize it to things like "Xcode Y.Z" and "VS 20XX toolchain Y.Z" as much as possible[1].

> The advantage over git hooks is that they run in the builder context, not in the context of the specific user that pushed a commit.

+100% I've come to distrust git hooks for "enforcement" of…anything because `git commit -n` exists. Verify things you care about centrally and report using your normal CI processes. Instead, hooks should be for workflow helpers (e.g., `git-lfs` data shuttling or syncing with a remote's version of your topic).

[1] Some packages are real PITA to manage and require global installation. So far, this has just been Windows for MPI and GPU driver installations.