SHA-256 outputs of fixed-output derivations. I.e. they now produce
the same store path:
$ nix-store --add x
/nix/store/j2fq9qxvvxgqymvpszhs773ncci45xsj-x
$ nix-store --add-fixed --recursive sha256 x
/nix/store/j2fq9qxvvxgqymvpszhs773ncci45xsj-x
the latter being the same as the path that a derivation
derivation {
name = "x";
outputHashAlgo = "sha256";
outputHashMode = "recursive";
outputHash = "...";
...
};
produces.
This does change the output path for such fixed-output derivations.
Fortunately they are quite rare. The most common use is fetchsvn
calls with SHA-256 hashes. (There are a handful of those is
Nixpkgs, mostly unstable development packages.)
* Documented the computation of store paths (in store-api.cc).
This isn't usually a problem, except that it causes tests to fail
when performed in a directory with a very long path name. So chdir
to the socket directory and use a relative path name.
(/nix/var/nix/daemon-socket). This allows access to the Nix daemon
to be restricted by setting the mode/ownership on that directory as
desired, e.g.
$ chmod 770 /nix/var/nix/daemon-socket
$ chown root.wheel /nix/var/nix/daemon-socket
to allow only users in the wheel group to use Nix.
Setting the ownership on a socket is much trickier, since the socket
must be deleted and recreated every time the daemon is started
(which would require additional Nix configuration file directives to
specify the mode/ownership, and wouldn't support arbitrary ACLs),
some BSD variants appear to ignore permissions on sockets, and it's
not clear whether the umask is respected on every platform when
creating sockets.
from a source directory. All files for which a predicate function
returns true are copied to the store. Typical example is to leave
out the .svn directory:
stdenv.mkDerivation {
...
src = builtins.filterSource
(path: baseNameOf (toString path) != ".svn")
./source-dir;
# as opposed to
# src = ./source-dir;
}
This is important because the .svn directory influences the hash in
a rather unpredictable and variable way.
