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diff --git a/doc/manual/release-notes/rl-12.xml b/doc/manual/release-notes/rl-12.xml new file mode 100644 index 000000000..72d164f00 --- /dev/null +++ b/doc/manual/release-notes/rl-12.xml @@ -0,0 +1,157 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-1.2"> + +<title>Release 1.2 (December 6, 2012)</title> + +<para>This release has the following improvements and changes:</para> + +<itemizedlist> + + <listitem> + <para>Nix has a new binary substituter mechanism: the + <emphasis>binary cache</emphasis>. A binary cache contains + pre-built binaries of Nix packages. Whenever Nix wants to build a + missing Nix store path, it will check a set of binary caches to + see if any of them has a pre-built binary of that path. The + configuration setting <option>binary-caches</option> contains a + list of URLs of binary caches. For instance, doing +<screen> +$ nix-env -i thunderbird --option binary-caches http://cache.nixos.org +</screen> + will install Thunderbird and its dependencies, using the available + pre-built binaries in <uri>http://cache.nixos.org</uri>. + The main advantage over the old “manifest”-based method of getting + pre-built binaries is that you don’t have to worry about your + manifest being in sync with the Nix expressions you’re installing + from; i.e., you don’t need to run <command>nix-pull</command> to + update your manifest. It’s also more scalable because you don’t + need to redownload a giant manifest file every time. + </para> + + <para>A Nix channel can provide a binary cache URL that will be + used automatically if you subscribe to that channel. If you use + the Nixpkgs or NixOS channels + (<uri>http://nixos.org/channels</uri>) you automatically get the + cache <uri>http://cache.nixos.org</uri>.</para> + + <para>Binary caches are created using <command>nix-push</command>. + For details on the operation and format of binary caches, see the + <command>nix-push</command> manpage. More details are provided in + <link xlink:href="http://lists.science.uu.nl/pipermail/nix-dev/2012-September/009826.html">this + nix-dev posting</link>.</para> + </listitem> + + <listitem> + <para>Multiple output support should now be usable. A derivation + can declare that it wants to produce multiple store paths by + saying something like +<programlisting> +outputs = [ "lib" "headers" "doc" ]; +</programlisting> + This will cause Nix to pass the intended store path of each output + to the builder through the environment variables + <literal>lib</literal>, <literal>headers</literal> and + <literal>doc</literal>. Other packages can refer to a specific + output by referring to + <literal><replaceable>pkg</replaceable>.<replaceable>output</replaceable></literal>, + e.g. +<programlisting> +buildInputs = [ pkg.lib pkg.headers ]; +</programlisting> + If you install a package with multiple outputs using + <command>nix-env</command>, each output path will be symlinked + into the user environment.</para> + </listitem> + + <listitem> + <para>Dashes are now valid as part of identifiers and attribute + names.</para> + </listitem> + + <listitem> + <para>The new operation <command>nix-store --repair-path</command> + allows corrupted or missing store paths to be repaired by + redownloading them. <command>nix-store --verify --check-contents + --repair</command> will scan and repair all paths in the Nix + store. Similarly, <command>nix-env</command>, + <command>nix-build</command>, <command>nix-instantiate</command> + and <command>nix-store --realise</command> have a + <option>--repair</option> flag to detect and fix bad paths by + rebuilding or redownloading them.</para> + </listitem> + + <listitem> + <para>Nix no longer sets the immutable bit on files in the Nix + store. Instead, the recommended way to guard the Nix store + against accidental modification on Linux is to make it a read-only + bind mount, like this: + +<screen> +$ mount --bind /nix/store /nix/store +$ mount -o remount,ro,bind /nix/store +</screen> + + Nix will automatically make <filename>/nix/store</filename> + writable as needed (using a private mount namespace) to allow + modifications.</para> + </listitem> + + <listitem> + <para>Store optimisation (replacing identical files in the store + with hard links) can now be done automatically every time a path + is added to the store. This is enabled by setting the + configuration option <literal>auto-optimise-store</literal> to + <literal>true</literal> (disabled by default).</para> + </listitem> + + <listitem> + <para>Nix now supports <command>xz</command> compression for NARs + in addition to <command>bzip2</command>. It compresses about 30% + better on typical archives and decompresses about twice as + fast.</para> + </listitem> + + <listitem> + <para>Basic Nix expression evaluation profiling: setting the + environment variable <envar>NIX_COUNT_CALLS</envar> to + <literal>1</literal> will cause Nix to print how many times each + primop or function was executed.</para> + </listitem> + + <listitem> + <para>New primops: <varname>concatLists</varname>, + <varname>elem</varname>, <varname>elemAt</varname> and + <varname>filter</varname>.</para> + </listitem> + + <listitem> + <para>The command <command>nix-copy-closure</command> has a new + flag <option>--use-substitutes</option> (<option>-s</option>) to + download missing paths on the target machine using the substitute + mechanism.</para> + </listitem> + + <listitem> + <para>The command <command>nix-worker</command> has been renamed + to <command>nix-daemon</command>. Support for running the Nix + worker in “slave” mode has been removed.</para> + </listitem> + + <listitem> + <para>The <option>--help</option> flag of every Nix command now + invokes <command>man</command>.</para> + </listitem> + + <listitem> + <para>Chroot builds are now supported on systemd machines.</para> + </listitem> + +</itemizedlist> + +<para>This release has contributions from Eelco Dolstra, Florian +Friesdorf, Mats Erik Andersson and Shea Levy.</para> + +</chapter>
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