nixpkgs/nixos/doc/manual/release-notes/rl-1703.xml
Nicolas B. Pierron f5dfe78a1e Add overlays mechanism to Nixpkgs.
This patch add a new argument to Nixpkgs default expression named "overlays".

By default, the value of the argument is either taken from the environment variable `NIXPKGS_OVERLAYS`,
or from the directory `~/.nixpkgs/overlays/`.  If the environment variable does not name a valid directory
then this mechanism would fallback on the home directory.  If the home directory does not exists it will
fallback on an empty list of overlays.

The overlays directory should contain the list of extra Nixpkgs stages which would be used to extend the
content of Nixpkgs, with additional set of packages.  The overlays, i-e directory, files, symbolic links
are used in alphabetical order.

The simplest overlay which extends Nixpkgs with nothing looks like:

```nix
self: super: {
}
```

More refined overlays can use `super` as the basis for building new packages, and `self` as a way to query
the final result of the fix-point.

An example of overlay which extends Nixpkgs with a small set of packages can be found at:
  https://github.com/nbp/nixpkgs-mozilla/blob/nixpkgs-overlay/moz-overlay.nix

To use this file, checkout the repository and add a symbolic link to
the `moz-overlay.nix` file in `~/.nixpkgs/overlays` directory.
2017-01-16 01:17:33 +01:00

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XML

<section 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="sec-release-17.03">
<title>Release 17.03 (“XXX”, 2017/03/??)</title>
<para>In addition to numerous new and upgraded packages, this release
has the following highlights: </para>
<itemizedlist>
<listitem>
<para>Nixpkgs is now extensible through <link
xlink:href="https://github.com/NixOS/nixpkgs/pull/21243">overlays</link>.
See the Nixpkgs manual for more information.</para>
</listitem>
</itemizedlist>
<para>The following new services were added since the last release:</para>
<itemizedlist>
<listitem>
<para></para>
</listitem>
</itemizedlist>
<para>When upgrading from a previous release, please be aware of the
following incompatible changes:</para>
<itemizedlist>
<listitem>
<para>
<literal>stdenv.overrides</literal> is now expected to take <literal>self</literal>
and <literal>super</literal> arguments. See <literal>lib.trivial.extends</literal>
for what those parameters represent.
</para>
</listitem>
<listitem>
<para>
<literal>gnome</literal> alias has been removed along with
<literal>gtk</literal>, <literal>gtkmm</literal> and several others.
Now you need to use versioned attributes, like <literal>gnome3</literal>.
</para>
</listitem>
<listitem>
<para>
The attribute name of the Radicale daemon has been changed from
<literal>pythonPackages.radicale</literal> to
<literal>radicale</literal>.
</para>
</listitem>
<listitem>
<para>
The Yama LSM is now enabled by default in the kernel,
which prevents ptracing non-child processes.
This means you will not be able to attach gdb to an existing process,
but will need to start that process from gdb (so it is a child).
</para>
</listitem>
<listitem>
<para>
The <literal>stripHash</literal> bash function in <literal>stdenv</literal>
changed according to its documentation; it now outputs the stripped name to
<literal>stdout</literal> instead of putting it in the variable
<literal>strippedName</literal>.
</para>
</listitem>
<listitem>
<para>PHP now scans for extra configuration .ini files in /etc/php.d
instead of /etc. This prevents accidentally loading non-PHP .ini files
that may be in /etc.
</para>
</listitem>
<listitem>
<para>
Parsoid service now uses YAML configuration format.
<literal>service.parsoid.interwikis</literal> is now called
<literal>service.parsoid.wikis</literal> and is a list of either API URLs
or attribute sets as specified in parsoid's documentation.
</para>
</listitem>
<listitem>
<para>
<literal>Ntpd</literal> was replaced by
<literal>systemd-timesyncd</literal> as the default service to synchronize
system time with a remote NTP server. The old behavior can be restored by
setting <literal>services.ntp.enable</literal> to <literal>true</literal>.
Upstream time servers for all NTP implementations are now configured using
<literal>networking.timeServers</literal>.
</para>
</listitem>
<listitem>
<para><literal>pkgs.overridePackages</literal> function no longer exists. Instead import Nixpkgs a second time using <literal>import pkgs.path {
overlays = [ <replaceable>...</replaceable> ]; }</literal>.</para>
</listitem>
</itemizedlist>
<para>Other notable improvements:</para>
<itemizedlist>
<listitem>
<para>Module type system have a new extensible option types feature that
allow to extend certain types, such as enum, through multiple option
declarations of the same option across multiple modules.
</para>
</listitem>
</itemizedlist>
</section>