In preparation for the switch from Subversion to Git, this release is mainly the prevent the Nixpkgs version number from going backwards. (This would happen because prerelease version numbers produced for the Git repository are lower than those for the Subversion repository.)
There are way too many additions to Nixpkgs since the last release to list here: for example, the number of packages on Linux has increased from 1002 to 2159. However, some specific improvements are worth listing:
Support for building derivations in a virtual machine, including RPM and Debian builds in automatically generated VM images. See <filename>pkgs/build-support/vm/default.nix</filename> for details.
The following people contributed to this release: Andres Löh, Arie Middelkoop, Armijn Hemel, Eelco Dolstra, Lluís Batlle, Ludovic Courtès, Marc Weber, Mart Kolthof, Martin Bravenboer, Michael Raskin, Nicolas Pierron, Peter Simons, Pjotr Prins, Rob Vermaas, Sander van der Burg, Tobias Hammerschmidt, Valentin David, Wouter den Breejen and Yury G. Kudryashov. In addition, several people contributed patches on the <literal>nix-dev</literal> mailing list.
The standard build environment (<literal>stdenv</literal>) is now pure on the <literal>x86_64-linux</literal> and <literal>powerpc-linux</literal> platforms, just as on <literal>i686-linux</literal>. (Purity means that building and using the standard environment has no dependencies outside of the Nix store. For instance, it doesn’t require an external C compiler such as <filename>/usr/bin/gcc</filename>.) Also, the statically linked binaries used in the bootstrap process are now automatically reproducible, making it easy to update the bootstrap tools and to add support for other Linux platforms. See <filename>pkgs/stdenv/linux/make-bootstrap-tools.nix</filename> for details.
Hook variables in the generic builder are now executed using the <function>eval</function> shell command. This has a major advantage: you can write hooks directly in Nix expressions. For instance, rather than writing a builder like this:
It is now possible to have the generic builder pass arguments to <command>configure</command> and <command>make</command> that contain whitespace. Previously, for example, you could say in a builder,
which does the right thing. Idem for <literal>makeFlags</literal>, <literal>installFlags</literal>, <literal>checkFlags</literal> and <literal>distFlags</literal>.
The function <function>fetchurl</function> now has support for two different kinds of mirroring of files. First, it has support for <emphasis>content-addressable mirrors</emphasis>. For example, given the <function>fetchurl</function> call
<function>fetchurl</function> will first try to download this file from <link
xlink:href="http://tarballs.nixos.org/sha1/eb72f55e4a8bf08e8c6ef227c0ade3d068ba1082"/>. If that file doesn’t exist, it will try the original URL. In general, the “content-addressed” location is <replaceable>mirror</replaceable><literal>/</literal><replaceable>hash-type</replaceable><literal>/</literal><replaceable>hash</replaceable>. There is currently only one content-addressable mirror (<link
xlink:href="http://tarballs.nixos.org"/>), but more can be specified in the <varname>hashedMirrors</varname> attribute in <filename>pkgs/build-support/fetchurl/mirrors.nix</filename>, or by setting the <envar>NIX_HASHED_MIRRORS</envar> environment variable to a whitespace-separated list of URLs.
Second, <function>fetchurl</function> has support for widely-mirrored distribution sites such as SourceForge or the Linux kernel archives. Given a URL of the form <literal>mirror://<replaceable>site</replaceable>/<replaceable>path</replaceable></literal>, it will try to download <replaceable>path</replaceable> from a configurable list of mirrors for <replaceable>site</replaceable>. (This idea was borrowed from Gentoo Linux.) Example:
Currently <replaceable>site</replaceable> can be <literal>sourceforge</literal>, <literal>gnu</literal> and <literal>kernel</literal>. The list of mirrors is defined in <filename>pkgs/build-support/fetchurl/mirrors.nix</filename>. You can override the list of mirrors for a particular site by setting the environment variable <envar>NIX_MIRRORS_<replaceable>site</replaceable></envar>, e.g.
The following people contributed to this release: Andres Löh, Arie Middelkoop, Armijn Hemel, Eelco Dolstra, Marc Weber, Mart Kolthof, Martin Bravenboer, Michael Raskin, Wouter den Breejen and Yury G. Kudryashov.
<filename>pkgs/system/all-packages-generic.nix</filename> is gone, we now just have <filename>pkgs/top-level/all-packages.nix</filename> that contains all available packages. This should cause much less confusion with users. <filename>all-packages.nix</filename> is a function that by default returns packages for the current platform, but you can override this by specifying a different <varname>system</varname> argument.
Certain packages in Nixpkgs are now user-configurable through a configuration file, i.e., without having to edit the Nix expressions in Nixpkgs. For instance, the Firefox provided in the Nixpkgs channel is built without the RealPlayer plugin (for legal reasons). Previously, you could easily enable RealPlayer support by editing the call to the Firefox function in <filename>all-packages.nix</filename>, but such changes are not respected when Firefox is subsequently updated through the Nixpkgs channel.
The Nixpkgs configuration file (found in <filename>~/.nixpkgs/config.nix</filename> or through the <envar>NIXPKGS_CONFIG</envar> environment variable) is an attribute set that contains configuration options that <filename>all-packages.nix</filename> reads and uses for certain packages. For instance, the following configuration file:
(Actually, <literal>firefox.enableRealPlayer</literal> is the <emphasis>only</emphasis> configuration option currently available, but more are sure to be added.)
<literal>i686-cygwin</literal>, i.e., Windows (using <linkxlink:href="http://www.cygwin.com/">Cygwin</link>). The standard environment on <literal>i686-cygwin</literal> by default builds binaries for the Cygwin environment (i.e., it uses Cygwin tools and produces executables that use the Cygwin library). However, there is also a standard environment that produces binaries that use <link
xlink:href="http://www.mingw.org/">MinGW</link>. You can use it by calling <filename>all-package.nix</filename> with the <varname>stdenvType</varname> argument set to <literal>"i686-mingw"</literal>.
<literal>x86_64-linux</literal>, i.e., Linux on 64-bit AMD/Intel CPUs. Unlike <literal>i686-linux</literal>, this platform doesn’t have a pure <literal>stdenv</literal> yet.
It is now <emphasis>much</emphasis> easier to override the default C compiler and other tools in <literal>stdenv</literal> for specific packages. <filename>all-packages.nix</filename> provides two utility functions for this purpose: <function>overrideGCC</function> and <function>overrideInStdenv</function>. Both take a <literal>stdenv</literal> and return an augmented <literal>stdenv</literal>; the formed changes the C compiler, and the latter adds additional packages to the front of <literal>stdenv</literal>’s initial <envar>PATH</envar>, allowing tools to be overridden.
For instance, the package <varname>strategoxt</varname> doesn’t build with the GNU Make in <literal>stdenv</literal> (version 3.81), so we call it with an augmented <literal>stdenv</literal> that uses GNU Make 3.80:
It has also become much easier to experiment with changes to the <literal>stdenv</literal> setup script (which notably contains the generic builder). Since edits to <filename>pkgs/stdenv/generic/setup.sh</filename> trigger a rebuild of <emphasis>everything</emphasis>, this was formerly quite painful. But now <literal>stdenv</literal> contains a function to “regenerate” <literal>stdenv</literal> with a different setup script, allowing the use of a different setup script for specific packages:
Packages can now have a human-readable <emphasis>description</emphasis> field. Package descriptions are shown by <literal>nix-env -qa --description</literal>. In addition, they’re shown on the Nixpkgs release page. A description can be added to a package as follows:
The <varname>meta</varname> attribute is not passed to the builder, so changes to the description do not trigger a rebuild. Additional <varname>meta</varname> attributes may be defined in the future (such as the URL of the package’s homepage, the license, etc.).
The following people contributed to this release: Andres Löh, Armijn Hemel, Christof Douma, Eelco Dolstra, Eelco Visser, Mart Kolthof, Martin Bravenboer, Merijn de Jonge, Rob Vermaas and Roy van den Broek.
There have been zillions of changes since the last release of Nixpkgs. Many packages have been added or updated. The following are some of the more notable changes:
The old, unofficial Xlibs has been replaced by the official modularised X11 distribution from X.org, i.e., X11R7.0. X11R7.0 consists of 287 (!) packages, all of which are in Nixpkgs though not all have been tested. It is now possible to build a working X server (previously we only had X client libraries). We use a fully Nixified X server on NixOS.
The Sun JDK 5 has been purified, i.e., it doesn’t require any non-Nix components such as <filename>/lib/ld-linux.so.2</filename>. This means that Java applications such as Eclipse and Azureus can run on NixOS.
The following people contributed to this release: Andres Löh, Armijn Hemel, Bogdan Dumitriu, Christof Douma, Eelco Dolstra, Eelco Visser, Mart Kolthof, Martin Bravenboer, Rob Vermaas and Roy van den Broek.
The bootstrap process for the standard build environment on Linux (stdenv-linux) has been improved. It is no longer dependent in its initial bootstrap stages on the system Glibc, GCC, and other tools. Rather, Nixpkgs contains a statically linked bash and curl, and uses that to download other statically linked tools. These are then used to build a Glibc and dynamically linked versions of all other tools.
Tarballs used by Nixpkgs are now obtained from the same server that hosts Nixpkgs (<link
xlink:href="http://catamaran.labs.cs.uu.nl/" />). This reduces the risk of packages being unbuildable due to moved or deleted files on various servers.
