But this just doesn't match my experience with Blaze at all. For my internal usage with C++ & Go it's perfect. For the weird niche use case of building and packaging BPF programs (with no support from the central tooling teams, we had to write our own macros) it still just works. For Python where it's a poor fit for the language norms it's a minor inconvenience but still mostly stays out of the way. I hear Java is similar.

For vendored open source projects that build with random other tools (CMake, Nix, custom Makefile) it's a pain but the fact that it's generally possible to get them building with Blaze at all says something...

Yes, the monorepo makes all of this dramatically easier. I can consider "one-build-tool-to-rule-them-all isn't really practical outside of a monorepo" as a valid argument, although it remains to be proven. But "you fundamentally need a build tool per language" doesn't hold any water for me.

> That makes it easier to work on other projects, and easier to write tooling that works with all of them.

But... this is my whole point. Only if those projects are in the same language as yours! I can see how maybe that's valid in some domains where there's probably a lot of people who can just do almost everything on JS/TS, maybe Java has a similar domain. But for most of us switching between Go/Cargo/CMake etc is a huge pain.

Oh btw, there's also Meson. That's very cross-language while also seeming extremely simple to use. But it doesn't seem to deliver a very full-featured experience.