It is unused in Nix currently, but will be used in Hydra. This reflects
what Hydra does in https://github.com/NixOS/hydra/pull/1387.
We may probably to use it more widely for better SSH store performance,
but this needs to be subject to more testing before we do that.
This is a first step towards PR #10760, and the issues it addresses.
See the Doxygen for details.
Thanks to these changes, we are able to drastically restrict how the
rest of the code-base uses `ParseDerivation`.
Co-Authored-By: HaeNoe <git@haenoe.party>
It's best we teach users that the "foo" derivation is less than pure in the sense that it cannot be built just on any system, in particular that builders cannot be selected arbitrarily but based on their system-features. The `"recursive-nix"` system-feature is automatically defined by `--extra-experimental-features recursive-nix`
Otherwise we may accidentally update a lock when we shouldn't.
Fixes#12445.
(cherry picked from commit 5c552b62fc)
# Conflicts:
# src/libflake/flake/flake.cc
I do not believe there is any problem with computing
`hashDerivationModulo` the normal way with impure derivations.
Conversely, the way this used to work is very suspicious because two
almost-equal derivations that only differ in depending on different
impure derivations could have the same drv hash modulo. That is very
suspicious because there is no reason to think those two different
impure derivations will end up producing the same content-addressed
data!
Co-authored-by: Alain Zscheile <zseri.devel@ytrizja.de>
E.g. in a derivation attribute `foo = ./bar`, if ./bar is a symlink,
we should copy the symlink to the store, not its target. This restores
the behaviour of Nix <= 2.19.
(cherry picked from commit 26b87e78b5)
E.g. in a derivation attribute `foo = ./bar`, if ./bar is a symlink,
we should copy the symlink to the store, not its target. This restores
the behaviour of Nix <= 2.19.
These don't need to evaluate anything (except for the flake metadata
in flake.nix) so we can make these commands operate on lazy trees
without risk of any semantic change in the evaluator.
However, `nix flake metadata` now no longer prints the store path,
which is a breaking change (but unavoidable if we want lazy trees).
