We immediately use this in the JSON schemas for Derivation and Deriving
Path, but we cannot yet use it in Store Object Info because those paths
*do* include the store dir currently.
See #13570 for details --- the idea is that included the store dir in
store paths makes systematic JSON parting with e.g. Serde, Aeson,
nlohmann, or similiar harder.
After talking to Eelco, we are changing the `Derivation` format right
away because not only is `nix derivation` technically experimental, we think it is
also less widely used in practice than, say, `nix path-info`.
Progress on #13570
Makes the behavoral change of #13263 without the underlying refactor.
Hopefully this clearly safe from a perf and GC perspective, and will
make it easier to benchmark #13263.
This is a big step documenting the store layer on its own, separately from the evaluator (and `builtins.derivation`).
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
