In Nixpkgs, the attribute in all-packages.nix corresponding to a
package is usually equal to the package name. However, this doesn't
work if the package contains a dash, which is fairly common. The
convention is to replace the dash with an underscore (e.g. "dbus-lib"
becomes "dbus_glib"), but that's annoying. So now dashes are valid in
variable / attribute names, allowing you to write:
dbus-glib = callPackage ../development/libraries/dbus-glib { };
and
buildInputs = [ dbus-glib ];
Since we don't have a negation or subtraction operation in Nix, this
is unambiguous.
If the options gc-keep-outputs and gc-keep-derivations are both
enabled, you can get a cycle in the liveness graph. There was a hack
to handle this, but it didn't work with multiple-output derivations,
causing the garbage collector to fail with errors like ‘error: cannot
delete path `...' because it is in use by `...'’. The garbage
collector now handles strongly connected components in the liveness
graph as a unit and decides whether to delete all or none of the paths
in an SCC.
Apparently our DBD::SQLite links against /usr/lib/libsqlite3.dylib,
which is an old version that doesn't respect foreign key constraints.
So manifests/cache.sqlite doesn't get updated properly when a manifest
disappears. We should fix our DBD::SQLite, but in the meantime this
will fix the test.
http://hydra.nixos.org/build/3017959
Querying all substitutable paths via "nix-env -qas" is potentially
hard on a server, since it involves sending thousands of HEAD
requests. So a binary cache must now have a meta-info file named
"nix-cache-info" that specifies whether the server wants this. It
also specifies the store prefix so that we don't send useless queries
to a binary cache for a different store prefix.
Since SubstitutionGoal::finished() in build.cc computes the hash
anyway, we can prevent the inefficiency of computing the hash twice by
letting the substituter tell Nix about the expected hash, which can
then verify it.
"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).
Ensuring that the tests work from the build tree requires a growing
number of nasty hacks. The tests also don't verify that the installed
Nix actually works. Thus, the tests now require "make install" to
have been run.
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.
other simplifications.
* Use <nix/...> to locate the corepkgs. This allows them to be
overriden through $NIX_PATH.
* Use bash's pipefail option in the NAR builder so that we don't need
to create a temporary file.
