From 1aa19b24b27c6bbf4d46cdd7f6d06b534dd67c19 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Tue, 18 Feb 2014 01:01:14 +0100 Subject: Add a flag ‘--check’ to verify build determinism MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The flag ‘--check’ to ‘nix-store -r’ or ‘nix-build’ will cause Nix to redo the build of a derivation whose output paths are already valid. If the new output differs from the original output, an error is printed. This makes it easier to test if a build is deterministic. (Obviously this cannot catch all sources of non-determinism, but it catches the most common one, namely the current time.) For example: $ nix-build '' -A patchelf ... $ nix-build '' -A patchelf --check error: derivation `/nix/store/1ipvxsdnbhl1rw6siz6x92s7sc8nwkkb-patchelf-0.6' may not be deterministic: hash mismatch in output `/nix/store/4pc1dmw5xkwmc6q3gdc9i5nbjl4dkjpp-patchelf-0.6.drv' The --check build fails if not all outputs are valid. Thus the first call to nix-build is necessary to ensure that all outputs are valid. The current outputs are left untouched: the new outputs are either put in a chroot or diverted to a different location in the store using hash rewriting. --- src/nix-env/nix-env.cc | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'src/nix-env/nix-env.cc') diff --git a/src/nix-env/nix-env.cc b/src/nix-env/nix-env.cc index e2781e540b..333a7fe8c0 100644 --- a/src/nix-env/nix-env.cc +++ b/src/nix-env/nix-env.cc @@ -714,7 +714,7 @@ static void opSet(Globals & globals, PathSet paths = singleton(drv.queryDrvPath()); printMissing(*store, paths); if (globals.dryRun) return; - store->buildPaths(paths, globals.state.repair); + store->buildPaths(paths, globals.state.repair ? bmRepair : bmNormal); } else { printMissing(*store, singleton(drv.queryOutPath())); -- cgit 1.4.1