Allow nix.conf options to be set in flake.nix

This makes it possible to have per-project configuration in flake.nix,
e.g. binary caches and other stuff:

  nixConfig.bash-prompt-suffix = "ngi# ";
  nixConfig.substituters = [ "https://cache.ngi0.nixos.org/" ];

1 files changed, 4 insertions, 1 deletions

diff --git a/src/nix/installables.cc b/src/nix/installables.cc
index 7473c9758..fb264491a 100644
--- a/src/nix/installables.cc
+++ b/src/nix/installables.cc
@@ -533,8 +533,11 @@ InstallableFlake::getCursors(EvalState & state)
 
 std::shared_ptr<flake::LockedFlake> InstallableFlake::getLockedFlake() const
 {
-    if (!_lockedFlake)
+    if (!_lockedFlake) {
         _lockedFlake = std::make_shared<flake::LockedFlake>(lockFlake(*state, flakeRef, lockFlags));
+        _lockedFlake->flake.config.apply();
+        // FIXME: send new config to the daemon.
+    }
     return _lockedFlake;
 }