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/libstore/store-api.hh | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'src/libstore/store-api.hh') diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh index a82fe3221639..047ccf4aa9bc 100644 --- a/src/libstore/store-api.hh +++ b/src/libstore/store-api.hh @@ -98,6 +98,9 @@ struct ValidPathInfo typedef list ValidPathInfos; +enum BuildMode { bmNormal, bmRepair, bmCheck }; + + class StoreAPI { public: @@ -190,7 +193,7 @@ public: output paths can be created by running the builder, after recursively building any sub-derivations. For inputs that are not derivations, substitute them. */ - virtual void buildPaths(const PathSet & paths, bool repair = false) = 0; + virtual void buildPaths(const PathSet & paths, BuildMode buildMode = bmNormal) = 0; /* Ensure that a path is valid. If it is not currently valid, it may be made valid by running a substitute (if defined for the -- cgit 1.4.1