[habitue]

Nix isn't great as a build system, because it throws a lot out and rebuilds everything when something changes. It's intended to get a correct, isolated package installed, not to maximize sharing.

Bazel goes through great pains to only rebuild the minimum necessary for correctness. It's able to do that because bazel build files get a lot more information about the source level dependencies than a Nix file does

[derkha]

Reading through https://bazel.build/designs/skyframe.html, this sounds pretty much like what would be possible with the aforementioned recursive Nix and content-addressed paths. Bazel might still win in practice since the overhead of a Nix build is pretty high, which gets even more important when you do them recursively for each file.