Buck2: Our open source build system

I'm missing some historical context here. This article goes out of its way to compare and contrast with Bazel. Even the usage conventions, build syntax (Starlark), and RBE API are the same as in Bazel.

Did FB fork Bazel in the early days but retain basically everything about it except the name? Why didn't they just...adopt Bazel, and contribute to it like any other open source project?

One thing you might be missing is that this is Buck2.

Buck (https://github.com/facebook/buck) has been open sourced for nearly 10 years now.

The lore I've heard is that former Googlers went to Facebook, built Buck based on Blaze, and Facebook open sourced that before Google open sourced Blaze (as Bazel).

The first pull to the Buck github repo was on May 8, 2013 (https://github.com/facebook/buck/pulls?q=is%3Apr+sort%3Acrea...). The first to Bazel was Sep 30, 2014 (https://github.com/bazelbuild/bazel/pulls?q=is%3Apr+sort%3Ac...).

Buck far predates Bazel, and was built by ex-googlers replicating Blaze.

Skylark was a later evolution, after the python scripts grew out of control, and a cue that fb took from Google long after Buck had been near-universally deployed for several years.

Smells like what FB did with Caffe vs. Caffe2, the two of which have nothing to do with each other.

At the time that FB started writing Buck, Bazel was not open source. I believe it did exist as Blaze internally at Google before FB started writing Buck. Facebook open sourced Buck before Google open sourced Blaze as Bazel.

Over time Facebook has been working to align Buck with Bazel, e.g. the conversion to Starlark syntax so tools such as Buildozer work on both systems. I believe Buck2 also now uses the same remote execution APIs as Bazel, but don't quote me on that.

I was visiting the Google Munich office on the day Google open sourced Blaze/Bazel. The Facebook Buck team sent a congratulations cake: https://photos.app.goo.gl/6KwE6qeD3i72kSo38

Amusingly, the cake was in German but most of the Bazel team didn't really speak German. But it was yummy.

Remote Execution is just a gRPC protocol -- bazel, buck1 and others implement it.

Blaze already existed when I was an intern in 2007.

Blaze is very old (from 2006), the history is described here: https://mike-bland.com/2012/10/01/tools.html#blaze-forge-src...

In the years that followed folks left Google and joined other companies and created similar build systems because blaze had a lot of advantages at scale. Facebook made Buck, Twitter made Pants. Blaze was still closed source inside Google. They all used the same python looking language.

In 2012 Twitter open sourced Pants: https://blog.twitter.com/engineering/en_us/a/2016/the-releas...

In 2013 Facebook open sourced Buck: https://en.m.wikipedia.org/wiki/Buck_(software)

In 2015 Google finally open sourced most of blaze, but renamed it bazel for copyright reasons. Some might argue they waited too long because clearly there was a lot of demand for such a system. :)

After that Twitter (mostly?) migrated to bazel and Facebook sort of stalled out on Buck. But then recently they decided to rewrite it from scratch to fix a lot of the architecture problems resulting in Buck2.

Buck2 looks pretty impressive and hopefully it gets the bazel folks moving faster. For example the analysis phase in bazel is very slow even inside Google, and Buck2 shows an alternative design that's much faster.

The direction the Bazel team seems to be going in is shortening the wall clock time by allowing for concurrent analysis and execution: https://github.com/bazelbuild/bazel/issues/14057.