Allow URLs in the Nix search path

E.g. to install "hello" from the latest Nixpkgs:

  $ nix-build '<nixpkgs>' -A hello -I nixpkgs=https://nixos.org/channels/nixpkgs-unstable/nixexprs.tar.xz

Or to install a specific version of NixOS:

  $ nixos-rebuild switch -I nixpkgs=https://github.com/NixOS/nixpkgs/archive/63def04891a0abc328b1b0b3a78ec02c58f48583.tar.gz

1 files changed, 2 insertions, 2 deletions

diff --git a/src/nix-env/nix-env.cc b/src/nix-env/nix-env.cc
index 10b95dad168c..5cf41e844e83 100644
--- a/src/nix-env/nix-env.cc
+++ b/src/nix-env/nix-env.cc
@@ -1423,6 +1423,8 @@ int main(int argc, char * * argv)
 
         if (!op) throw UsageError("no operation specified");
 
+        store = openStore();
+
         globals.state = std::shared_ptr<EvalState>(new EvalState(searchPath));
         globals.state->repair = repair;
 
@@ -1441,8 +1443,6 @@ int main(int argc, char * * argv)
                 : canonPath(settings.nixStateDir + "/profiles/default");
         }
 
-        store = openStore();
-
         op(globals, opFlags, opArgs);
 
         globals.state->printStats();