The author of Bazel came over to FB and wrote Buck from memory. In Google it’s called Blaze. Buck2 is a rewrite in rust and gets rid of the JVM dependence, so it builds projects faster but it’s slow to build buck2 itself (Rust compilation)
I believe this is an over simplification. Engineers who had used Blaze at Google reimplemented it at Facebook based on what they knew of how it worked.
Even Facebook's Buck launch blog does not offer this story of Bucks lineage and although the author worked on the Closure compiler at Google that is not all of Blaze.
