From d4dcffd64349bb52ad5f1b184bee5cc7c2be73b4 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Tue, 16 Jan 2018 18:50:38 +0100 Subject: Add pure evaluation mode In this mode, the following restrictions apply: * The builtins currentTime, currentSystem and storePath throw an error. * $NIX_PATH and -I are ignored. * fetchGit and fetchMercurial require a revision hash. * fetchurl and fetchTarball require a sha256 attribute. * No file system access is allowed outside of the paths returned by fetch{Git,Mercurial,url,Tarball}. Thus 'nix build -f ./foo.nix' is not allowed. Thus, the evaluation result is completely reproducible from the command line arguments. E.g. nix build --pure-eval '( let nix = fetchGit { url = https://github.com/NixOS/nixpkgs.git; rev = "9c927de4b179a6dd210dd88d34bda8af4b575680"; }; nixpkgs = fetchGit { url = https://github.com/NixOS/nixpkgs.git; ref = "release-17.09"; rev = "66b4de79e3841530e6d9c6baf98702aa1f7124e4"; }; in (import (nix + "/release.nix") { inherit nix nixpkgs; }).build.x86_64-linux )' The goal is to enable completely reproducible and traceable evaluation. For example, a NixOS configuration could be fully described by a single Git commit hash. 'nixos-rebuild' would do something like nix build --pure-eval '( (import (fetchGit { url = file:///my-nixos-config; rev = "..."; })).system ') where the Git repository /my-nixos-config would use further fetchGit calls or Git externals to fetch Nixpkgs and whatever other dependencies it has. Either way, the commit hash would uniquely identify the NixOS configuration and allow it to reproduced. --- src/nix-instantiate/nix-instantiate.cc | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'src/nix-instantiate') diff --git a/src/nix-instantiate/nix-instantiate.cc b/src/nix-instantiate/nix-instantiate.cc index 55ac007e8682..e05040a42deb 100644 --- a/src/nix-instantiate/nix-instantiate.cc +++ b/src/nix-instantiate/nix-instantiate.cc @@ -182,7 +182,7 @@ int main(int argc, char * * argv) for (auto & i : files) { Expr * e = fromArgs ? state.parseExprFromString(i, absPath(".")) - : state.parseExprFromFile(resolveExprPath(lookupFileArg(state, i))); + : state.parseExprFromFile(resolveExprPath(state.checkSourcePath(lookupFileArg(state, i)))); processExpr(state, attrPaths, parseOnly, strict, autoArgs, evalOnly, outputKind, xmlOutputSourceLocation, e); } -- cgit 1.4.1