[arianvanp]

Nix is not (yet) suitable for fine-grained (read file level) build targets though due to lack of recursive nix and content addressed store. This means you don't have early cut off and mass rebuilds if only one file changes; for example. Both are being worked on actively though.

[zellyn]

If I understand it correctly (unlikely), Nix has the degree of purely-functional rigor necessary to do this correctly, right? Sounds like it would eventually be awesome for Bazel usecases.

[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.