[zombiezen]

According to Build systems à la carte, "it is not possible to express dynamic dependencies in [Bazel's] user-defined build rules; however some of the pre-defined build rules require dynamic dependencies and the internal build engine can cope with them by using a restarting task scheduler, which is similar to that of Excel but does not use the calc chain." (p6)

IME import-from-derivation and similar in Nix is usually used for importing build configurations from remote repositories. Bazel has a repository rule system that is similar: https://bazel.build/extending/repo

So to answer your question: yes from the strictest possible definition, but in practice, I believe the tradeoffs are acceptable.

[Ericson2314]

You should look at Nix's experimental dynamic derivations, which provide functionality entirely at the level of derivation language / store layer.

[zombiezen]

Interesting! Thanks, hadn't seen that yet. (For anyone else curious, the RFC is here: https://github.com/NixOS/rfcs/blob/master/rfcs/0092-plan-dyn...)