Mandatory features are features that MUST be present in a derivation's
requiredSystemFeatures attribute. One application is performance
testing, where we have a dedicated machine to run performance tests
(and nothing else). Then we would add the label "perf" to the
machine's mandatory features and to the performance testing
derivations.
"nix-channel --add" now accepts a second argument: the channel name.
This allows channels to have a nicer name than (say) nixpkgs_unstable.
If no name is given, it defaults to the last component of the URL
(with "-unstable" or "-stable" removed).
Also, channels are now stored in a profile
(/nix/var/nix/profiles/per-user/$USER/channels). One advantage of
this is that it allows rollbacks (e.g. if "nix-channel --update" gives
an undesirable update).
Nix now requires SQLite and bzip2 to be pre-installed. SQLite is
detected using pkg-config. We required DBD::SQLite anyway, so
depending on SQLite is not a big problem.
The --with-bzip2, --with-openssl and --with-sqlite flags are gone.
environment of the given derivation in a format that can be sourced
by the shell, e.g.
$ eval "$(nix-store --print-env $(nix-instantiate /etc/nixos/nixpkgs -A pkg))"
$ NIX_BUILD_TOP=/tmp
$ source $stdenv/setup
This is especially useful to reproduce the environment used to build
a package outside of its builder for development purposes.
TODO: add a nix-build option to do the above and fetch the
dependencies of the derivation as well.
the contents of any of the given store paths have been modified.
E.g.
$ nix-store --verify-path $(nix-store -qR /var/run/current-system)
path `/nix/store/m2smyiwbxidlprfxfz4rjlvz2c3mg58y-etc' was modified! expected hash `fc87e271c5fdf179b47939b08ad13440493805584b35e3014109d04d8436e7b8', got `20f1a47281b3c0cbe299ce47ad5ca7340b20ab34246426915fce0ee9116483aa'
All paths are checked; the exit code is 1 if any path has been
modified, 0 otherwise.
brackets, e.g.
import <nixpkgs/pkgs/lib>
are resolved by looking them up relative to the elements listed in
the search path. This allows us to get rid of hacks like
import "${builtins.getEnv "NIXPKGS_ALL"}/pkgs/lib"
The search path can be specified through the ‘-I’ command-line flag
and through the colon-separated ‘NIX_PATH’ environment variable,
e.g.,
$ nix-build -I /etc/nixos ...
If a file is not found in the search path, an error message is
lazily thrown.
(Linux) machines no longer maintain the atime because it's too
expensive, and on the machines where --use-atime is useful (like the
buildfarm), reading the atimes on the entire Nix store takes way too
much time to make it practical.
NixOS evaluation errors in particular look intimidating and
generally aren't very useful. Ideally the builtins.throw messages
should be self-contained.
UTC) rather than 0 (00:00:00). 1 is a better choice because some
programs use 0 as a special value. For instance, the Template
Toolkit uses a timestamp of 0 to denote the non-existence of a file,
so it barfs on files in the Nix store (see
template-toolkit-nix-store.patch in Nixpkgs). Similarly, Maya 2008
fails to load script directories with a timestamp of 0 and can't be
patched because it's closed source.
This will also shut up those "implausibly old time stamp" GNU tar
warnings.
logic through the `parseDrvName' and `compareVersions' primops.
This will allow expressions to easily check whether some dependency
is a specific needed version or falls in some version range. See
tests/lang/eval-okay-versions.nix for examples.
