mirror of
https://github.com/NixOS/nixpkgs.git
synced 2024-11-26 23:52:33 +00:00
681 lines
23 KiB
XML
681 lines
23 KiB
XML
<chapter xmlns="http://docbook.org/ns/docbook"
|
||
xmlns:xlink="http://www.w3.org/1999/xlink"
|
||
xml:id="chap-conventions">
|
||
|
||
<title>Coding conventions</title>
|
||
|
||
|
||
<section xml:id="sec-syntax"><title>Syntax</title>
|
||
|
||
<itemizedlist>
|
||
|
||
<listitem><para>Use 2 spaces of indentation per indentation level in
|
||
Nix expressions, 4 spaces in shell scripts.</para></listitem>
|
||
|
||
<listitem><para>Do not use tab characters, i.e. configure your
|
||
editor to use soft tabs. For instance, use <literal>(setq-default
|
||
indent-tabs-mode nil)</literal> in Emacs. Everybody has different
|
||
tab settings so it’s asking for trouble.</para></listitem>
|
||
|
||
<listitem><para>Use <literal>lowerCamelCase</literal> for variable
|
||
names, not <literal>UpperCamelCase</literal>. TODO: naming of
|
||
attributes in
|
||
<filename>all-packages.nix</filename>?</para></listitem>
|
||
|
||
<listitem><para>Function calls with attribute set arguments are
|
||
written as
|
||
|
||
<programlisting>
|
||
foo {
|
||
arg = ...;
|
||
}
|
||
</programlisting>
|
||
|
||
not
|
||
|
||
<programlisting>
|
||
foo
|
||
{
|
||
arg = ...;
|
||
}
|
||
</programlisting>
|
||
|
||
Also fine is
|
||
|
||
<programlisting>
|
||
foo { arg = ...; }
|
||
</programlisting>
|
||
|
||
if it's a short call.</para></listitem>
|
||
|
||
<listitem><para>In attribute sets or lists that span multiple lines,
|
||
the attribute names or list elements should be aligned:
|
||
|
||
<programlisting>
|
||
# A long list.
|
||
list =
|
||
[ elem1
|
||
elem2
|
||
elem3
|
||
];
|
||
|
||
# A long attribute set.
|
||
attrs =
|
||
{ attr1 = short_expr;
|
||
attr2 =
|
||
if true then big_expr else big_expr;
|
||
};
|
||
|
||
# Alternatively:
|
||
attrs = {
|
||
attr1 = short_expr;
|
||
attr2 =
|
||
if true then big_expr else big_expr;
|
||
};
|
||
</programlisting>
|
||
|
||
</para></listitem>
|
||
|
||
<listitem><para>Short lists or attribute sets can be written on one
|
||
line:
|
||
|
||
<programlisting>
|
||
# A short list.
|
||
list = [ elem1 elem2 elem3 ];
|
||
|
||
# A short set.
|
||
attrs = { x = 1280; y = 1024; };
|
||
</programlisting>
|
||
|
||
</para></listitem>
|
||
|
||
<listitem><para>Breaking in the middle of a function argument can
|
||
give hard-to-read code, like
|
||
|
||
<programlisting>
|
||
someFunction { x = 1280;
|
||
y = 1024; } otherArg
|
||
yetAnotherArg
|
||
</programlisting>
|
||
|
||
(especially if the argument is very large, spanning multiple
|
||
lines).</para>
|
||
|
||
<para>Better:
|
||
|
||
<programlisting>
|
||
someFunction
|
||
{ x = 1280; y = 1024; }
|
||
otherArg
|
||
yetAnotherArg
|
||
</programlisting>
|
||
|
||
or
|
||
|
||
<programlisting>
|
||
let res = { x = 1280; y = 1024; };
|
||
in someFunction res otherArg yetAnotherArg
|
||
</programlisting>
|
||
|
||
</para></listitem>
|
||
|
||
<listitem><para>The bodies of functions, asserts, and withs are not
|
||
indented to prevent a lot of superfluous indentation levels, i.e.
|
||
|
||
<programlisting>
|
||
{ arg1, arg2 }:
|
||
assert system == "i686-linux";
|
||
stdenv.mkDerivation { ...
|
||
</programlisting>
|
||
|
||
not
|
||
|
||
<programlisting>
|
||
{ arg1, arg2 }:
|
||
assert system == "i686-linux";
|
||
stdenv.mkDerivation { ...
|
||
</programlisting>
|
||
|
||
</para></listitem>
|
||
|
||
<listitem><para>Function formal arguments are written as:
|
||
|
||
<programlisting>
|
||
{ arg1, arg2, arg3 }:
|
||
</programlisting>
|
||
|
||
but if they don't fit on one line they're written as:
|
||
|
||
<programlisting>
|
||
{ arg1, arg2, arg3
|
||
, arg4, ...
|
||
, # Some comment...
|
||
argN
|
||
}:
|
||
</programlisting>
|
||
|
||
</para></listitem>
|
||
|
||
<listitem><para>Functions should list their expected arguments as
|
||
precisely as possible. That is, write
|
||
|
||
<programlisting>
|
||
{ stdenv, fetchurl, perl }: <replaceable>...</replaceable>
|
||
</programlisting>
|
||
|
||
instead of
|
||
|
||
<programlisting>
|
||
args: with args; <replaceable>...</replaceable>
|
||
</programlisting>
|
||
|
||
or
|
||
|
||
<programlisting>
|
||
{ stdenv, fetchurl, perl, ... }: <replaceable>...</replaceable>
|
||
</programlisting>
|
||
|
||
</para>
|
||
|
||
<para>For functions that are truly generic in the number of
|
||
arguments (such as wrappers around <varname>mkDerivation</varname>)
|
||
that have some required arguments, you should write them using an
|
||
<literal>@</literal>-pattern:
|
||
|
||
<programlisting>
|
||
{ stdenv, doCoverageAnalysis ? false, ... } @ args:
|
||
|
||
stdenv.mkDerivation (args // {
|
||
<replaceable>...</replaceable> if doCoverageAnalysis then "bla" else "" <replaceable>...</replaceable>
|
||
})
|
||
</programlisting>
|
||
|
||
instead of
|
||
|
||
<programlisting>
|
||
args:
|
||
|
||
args.stdenv.mkDerivation (args // {
|
||
<replaceable>...</replaceable> if args ? doCoverageAnalysis && args.doCoverageAnalysis then "bla" else "" <replaceable>...</replaceable>
|
||
})
|
||
</programlisting>
|
||
|
||
</para></listitem>
|
||
|
||
</itemizedlist>
|
||
|
||
</section>
|
||
|
||
|
||
<section xml:id="sec-package-naming"><title>Package naming</title>
|
||
|
||
<para>In Nixpkgs, there are generally three different names associated with a package:
|
||
|
||
<itemizedlist>
|
||
|
||
<listitem><para>The <varname>name</varname> attribute of the
|
||
derivation (excluding the version part). This is what most users
|
||
see, in particular when using
|
||
<command>nix-env</command>.</para></listitem>
|
||
|
||
<listitem><para>The variable name used for the instantiated package
|
||
in <filename>all-packages.nix</filename>, and when passing it as a
|
||
dependency to other functions. This is what Nix expression authors
|
||
see. It can also be used when installing using <command>nix-env
|
||
-iA</command>.</para></listitem>
|
||
|
||
<listitem><para>The filename for (the directory containing) the Nix
|
||
expression.</para></listitem>
|
||
|
||
</itemizedlist>
|
||
|
||
Most of the time, these are the same. For instance, the package
|
||
<literal>e2fsprogs</literal> has a <varname>name</varname> attribute
|
||
<literal>"e2fsprogs-<replaceable>version</replaceable>"</literal>, is
|
||
bound to the variable name <varname>e2fsprogs</varname> in
|
||
<filename>all-packages.nix</filename>, and the Nix expression is in
|
||
<filename>pkgs/os-specific/linux/e2fsprogs/default.nix</filename>.
|
||
</para>
|
||
|
||
<para>There are a few naming guidelines:
|
||
|
||
<itemizedlist>
|
||
|
||
<listitem><para>Generally, try to stick to the upstream package
|
||
name.</para></listitem>
|
||
|
||
<listitem><para>Don’t use uppercase letters in the
|
||
<literal>name</literal> attribute — e.g.,
|
||
<literal>"mplayer-1.0rc2"</literal> instead of
|
||
<literal>"MPlayer-1.0rc2"</literal>.</para></listitem>
|
||
|
||
<listitem><para>The version part of the <literal>name</literal>
|
||
attribute <emphasis>must</emphasis> start with a digit (following a
|
||
dash) — e.g., <literal>"hello-0.3.1rc2"</literal>.</para></listitem>
|
||
|
||
<listitem><para>If a package is not a release but a commit from a repository, then
|
||
the version part of the name <emphasis>must</emphasis> be the date of that
|
||
(fetched) commit. The date must be in <literal>"YYYY-MM-DD"</literal> format.
|
||
Also append <literal>"unstable"</literal> to the name - e.g.,
|
||
<literal>"pkgname-unstable-2014-09-23"</literal>.</para></listitem>
|
||
|
||
<listitem><para>Dashes in the package name should be preserved
|
||
in new variable names, rather than converted to underscores
|
||
(which was convention up to around 2013 and most names
|
||
still have underscores instead of dashes) — e.g.,
|
||
<varname>http-parser</varname> instead of
|
||
<varname>http_parser</varname>.</para></listitem>
|
||
|
||
<listitem><para>If there are multiple versions of a package, this
|
||
should be reflected in the variable names in
|
||
<filename>all-packages.nix</filename>,
|
||
e.g. <varname>json-c-0-9</varname> and <varname>json-c-0-11</varname>.
|
||
If there is an obvious “default” version, make an attribute like
|
||
<literal>json-c = json-c-0-9;</literal>.
|
||
See also <xref linkend="sec-versioning" /></para></listitem>
|
||
|
||
</itemizedlist>
|
||
|
||
</para>
|
||
|
||
</section>
|
||
|
||
|
||
<section xml:id="sec-organisation"><title>File naming and organisation</title>
|
||
|
||
<para>Names of files and directories should be in lowercase, with
|
||
dashes between words — not in camel case. For instance, it should be
|
||
<filename>all-packages.nix</filename>, not
|
||
<filename>allPackages.nix</filename> or
|
||
<filename>AllPackages.nix</filename>.</para>
|
||
|
||
<section xml:id="sec-hierarchy"><title>Hierarchy</title>
|
||
|
||
<para>Each package should be stored in its own directory somewhere in
|
||
the <filename>pkgs/</filename> tree, i.e. in
|
||
<filename>pkgs/<replaceable>category</replaceable>/<replaceable>subcategory</replaceable>/<replaceable>...</replaceable>/<replaceable>pkgname</replaceable></filename>.
|
||
Below are some rules for picking the right category for a package.
|
||
Many packages fall under several categories; what matters is the
|
||
<emphasis>primary</emphasis> purpose of a package. For example, the
|
||
<literal>libxml2</literal> package builds both a library and some
|
||
tools; but it’s a library foremost, so it goes under
|
||
<filename>pkgs/development/libraries</filename>.</para>
|
||
|
||
<para>When in doubt, consider refactoring the
|
||
<filename>pkgs/</filename> tree, e.g. creating new categories or
|
||
splitting up an existing category.</para>
|
||
|
||
<variablelist>
|
||
<varlistentry>
|
||
<term>If it’s used to support <emphasis>software development</emphasis>:</term>
|
||
<listitem>
|
||
<variablelist>
|
||
<varlistentry>
|
||
<term>If it’s a <emphasis>library</emphasis> used by other packages:</term>
|
||
<listitem>
|
||
<para><filename>development/libraries</filename> (e.g. <filename>libxml2</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s a <emphasis>compiler</emphasis>:</term>
|
||
<listitem>
|
||
<para><filename>development/compilers</filename> (e.g. <filename>gcc</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s an <emphasis>interpreter</emphasis>:</term>
|
||
<listitem>
|
||
<para><filename>development/interpreters</filename> (e.g. <filename>guile</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s a (set of) development <emphasis>tool(s)</emphasis>:</term>
|
||
<listitem>
|
||
<variablelist>
|
||
<varlistentry>
|
||
<term>If it’s a <emphasis>parser generator</emphasis> (including lexers):</term>
|
||
<listitem>
|
||
<para><filename>development/tools/parsing</filename> (e.g. <filename>bison</filename>, <filename>flex</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s a <emphasis>build manager</emphasis>:</term>
|
||
<listitem>
|
||
<para><filename>development/tools/build-managers</filename> (e.g. <filename>gnumake</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>Else:</term>
|
||
<listitem>
|
||
<para><filename>development/tools/misc</filename> (e.g. <filename>binutils</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
</variablelist>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>Else:</term>
|
||
<listitem>
|
||
<para><filename>development/misc</filename></para>
|
||
</listitem>
|
||
</varlistentry>
|
||
</variablelist>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s a (set of) <emphasis>tool(s)</emphasis>:</term>
|
||
<listitem>
|
||
<para>(A tool is a relatively small program, especially one intented
|
||
to be used non-interactively.)</para>
|
||
<variablelist>
|
||
<varlistentry>
|
||
<term>If it’s for <emphasis>networking</emphasis>:</term>
|
||
<listitem>
|
||
<para><filename>tools/networking</filename> (e.g. <filename>wget</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s for <emphasis>text processing</emphasis>:</term>
|
||
<listitem>
|
||
<para><filename>tools/text</filename> (e.g. <filename>diffutils</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s a <emphasis>system utility</emphasis>, i.e.,
|
||
something related or essential to the operation of a
|
||
system:</term>
|
||
<listitem>
|
||
<para><filename>tools/system</filename> (e.g. <filename>cron</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s an <emphasis>archiver</emphasis> (which may
|
||
include a compression function):</term>
|
||
<listitem>
|
||
<para><filename>tools/archivers</filename> (e.g. <filename>zip</filename>, <filename>tar</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s a <emphasis>compression</emphasis> program:</term>
|
||
<listitem>
|
||
<para><filename>tools/compression</filename> (e.g. <filename>gzip</filename>, <filename>bzip2</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s a <emphasis>security</emphasis>-related program:</term>
|
||
<listitem>
|
||
<para><filename>tools/security</filename> (e.g. <filename>nmap</filename>, <filename>gnupg</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>Else:</term>
|
||
<listitem>
|
||
<para><filename>tools/misc</filename></para>
|
||
</listitem>
|
||
</varlistentry>
|
||
</variablelist>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s a <emphasis>shell</emphasis>:</term>
|
||
<listitem>
|
||
<para><filename>shells</filename> (e.g. <filename>bash</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s a <emphasis>server</emphasis>:</term>
|
||
<listitem>
|
||
<variablelist>
|
||
<varlistentry>
|
||
<term>If it’s a web server:</term>
|
||
<listitem>
|
||
<para><filename>servers/http</filename> (e.g. <filename>apache-httpd</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s an implementation of the X Windowing System:</term>
|
||
<listitem>
|
||
<para><filename>servers/x11</filename> (e.g. <filename>xorg</filename> — this includes the client libraries and programs)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>Else:</term>
|
||
<listitem>
|
||
<para><filename>servers/misc</filename></para>
|
||
</listitem>
|
||
</varlistentry>
|
||
</variablelist>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s a <emphasis>desktop environment</emphasis>:</term>
|
||
<listitem>
|
||
<para><filename>desktops</filename> (e.g. <filename>kde</filename>, <filename>gnome</filename>, <filename>enlightenment</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s a <emphasis>window manager</emphasis>:</term>
|
||
<listitem>
|
||
<para><filename>applications/window-managers</filename> (e.g. <filename>awesome</filename>, <filename>compiz</filename>, <filename>stumpwm</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s an <emphasis>application</emphasis>:</term>
|
||
<listitem>
|
||
<para>A (typically large) program with a distinct user
|
||
interface, primarily used interactively.</para>
|
||
<variablelist>
|
||
<varlistentry>
|
||
<term>If it’s a <emphasis>version management system</emphasis>:</term>
|
||
<listitem>
|
||
<para><filename>applications/version-management</filename> (e.g. <filename>subversion</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s for <emphasis>video playback / editing</emphasis>:</term>
|
||
<listitem>
|
||
<para><filename>applications/video</filename> (e.g. <filename>vlc</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s for <emphasis>graphics viewing / editing</emphasis>:</term>
|
||
<listitem>
|
||
<para><filename>applications/graphics</filename> (e.g. <filename>gimp</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s for <emphasis>networking</emphasis>:</term>
|
||
<listitem>
|
||
<variablelist>
|
||
<varlistentry>
|
||
<term>If it’s a <emphasis>mailreader</emphasis>:</term>
|
||
<listitem>
|
||
<para><filename>applications/networking/mailreaders</filename> (e.g. <filename>thunderbird</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s a <emphasis>newsreader</emphasis>:</term>
|
||
<listitem>
|
||
<para><filename>applications/networking/newsreaders</filename> (e.g. <filename>pan</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s a <emphasis>web browser</emphasis>:</term>
|
||
<listitem>
|
||
<para><filename>applications/networking/browsers</filename> (e.g. <filename>firefox</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>Else:</term>
|
||
<listitem>
|
||
<para><filename>applications/networking/misc</filename></para>
|
||
</listitem>
|
||
</varlistentry>
|
||
</variablelist>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>Else:</term>
|
||
<listitem>
|
||
<para><filename>applications/misc</filename></para>
|
||
</listitem>
|
||
</varlistentry>
|
||
</variablelist>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s <emphasis>data</emphasis> (i.e., does not have a
|
||
straight-forward executable semantics):</term>
|
||
<listitem>
|
||
<variablelist>
|
||
<varlistentry>
|
||
<term>If it’s a <emphasis>font</emphasis>:</term>
|
||
<listitem>
|
||
<para><filename>data/fonts</filename></para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s related to <emphasis>SGML/XML processing</emphasis>:</term>
|
||
<listitem>
|
||
<variablelist>
|
||
<varlistentry>
|
||
<term>If it’s an <emphasis>XML DTD</emphasis>:</term>
|
||
<listitem>
|
||
<para><filename>data/sgml+xml/schemas/xml-dtd</filename> (e.g. <filename>docbook</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s an <emphasis>XSLT stylesheet</emphasis>:</term>
|
||
<listitem>
|
||
<para>(Okay, these are executable...)</para>
|
||
<para><filename>data/sgml+xml/stylesheets/xslt</filename> (e.g. <filename>docbook-xsl</filename>)</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
</variablelist>
|
||
</listitem>
|
||
</varlistentry>
|
||
</variablelist>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>If it’s a <emphasis>game</emphasis>:</term>
|
||
<listitem>
|
||
<para><filename>games</filename></para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term>Else:</term>
|
||
<listitem>
|
||
<para><filename>misc</filename></para>
|
||
</listitem>
|
||
</varlistentry>
|
||
</variablelist>
|
||
|
||
</section>
|
||
|
||
<section xml:id="sec-versioning"><title>Versioning</title>
|
||
|
||
<para>Because every version of a package in Nixpkgs creates a
|
||
potential maintenance burden, old versions of a package should not be
|
||
kept unless there is a good reason to do so. For instance, Nixpkgs
|
||
contains several versions of GCC because other packages don’t build
|
||
with the latest version of GCC. Other examples are having both the
|
||
latest stable and latest pre-release version of a package, or to keep
|
||
several major releases of an application that differ significantly in
|
||
functionality.</para>
|
||
|
||
<para>If there is only one version of a package, its Nix expression
|
||
should be named <filename>e2fsprogs/default.nix</filename>. If there
|
||
are multiple versions, this should be reflected in the filename,
|
||
e.g. <filename>e2fsprogs/1.41.8.nix</filename> and
|
||
<filename>e2fsprogs/1.41.9.nix</filename>. The version in the
|
||
filename should leave out unnecessary detail. For instance, if we
|
||
keep the latest Firefox 2.0.x and 3.5.x versions in Nixpkgs, they
|
||
should be named <filename>firefox/2.0.nix</filename> and
|
||
<filename>firefox/3.5.nix</filename>, respectively (which, at a given
|
||
point, might contain versions <literal>2.0.0.20</literal> and
|
||
<literal>3.5.4</literal>). If a version requires many auxiliary
|
||
files, you can use a subdirectory for each version,
|
||
e.g. <filename>firefox/2.0/default.nix</filename> and
|
||
<filename>firefox/3.5/default.nix</filename>.</para>
|
||
|
||
<para>All versions of a package <emphasis>must</emphasis> be included
|
||
in <filename>all-packages.nix</filename> to make sure that they
|
||
evaluate correctly.</para>
|
||
|
||
</section>
|
||
|
||
</section>
|
||
<section xml:id="sec-sources"><title>Fetching Sources</title>
|
||
<para>There are multiple ways to fetch a package source in nixpkgs. The
|
||
general guidline is that you should package sources with a high degree of
|
||
availability. Right now there is only one fetcher which has mirroring
|
||
support and that is <literal>fetchurl</literal>. Note that you should also
|
||
prefer protocols which have a corresponding proxy environment variable.
|
||
</para>
|
||
<para>You can find many source fetch helpers in <literal>pkgs/build-support/fetch*</literal>.
|
||
</para>
|
||
<para>In the file <literal>pkgs/top-level/all-packages.nix</literal> you can
|
||
find fetch helpers, these have names on the form
|
||
<literal>fetchFrom*</literal>. The intention of these are to provide
|
||
snapshot fetches but using the same api as some of the version controlled
|
||
fetchers from <literal>pkgs/build-support/</literal>. As an example going
|
||
from bad to good:
|
||
<itemizedlist>
|
||
<listitem>
|
||
<para>Uses <literal>git://</literal> which won't be proxied.
|
||
<programlisting>
|
||
src = fetchgit {
|
||
url = "git://github.com/NixOS/nix.git";
|
||
rev = "1f795f9f44607cc5bec70d1300150bfefcef2aae";
|
||
sha256 = "1cw5fszffl5pkpa6s6wjnkiv6lm5k618s32sp60kvmvpy7a2v9kg";
|
||
}
|
||
</programlisting>
|
||
</para>
|
||
</listitem>
|
||
<listitem>
|
||
<para>This is ok, but an archive fetch will still be faster.
|
||
<programlisting>
|
||
src = fetchgit {
|
||
url = "https://github.com/NixOS/nix.git";
|
||
rev = "1f795f9f44607cc5bec70d1300150bfefcef2aae";
|
||
sha256 = "1cw5fszffl5pkpa6s6wjnkiv6lm5k618s32sp60kvmvpy7a2v9kg";
|
||
}
|
||
</programlisting>
|
||
</para>
|
||
</listitem>
|
||
<listitem>
|
||
<para>Fetches a snapshot archive and you get the rev you want.
|
||
<programlisting>
|
||
src = fetchFromGitHub {
|
||
owner = "NixOS";
|
||
repo = "nix";
|
||
rev = "1f795f9f44607cc5bec70d1300150bfefcef2aae";
|
||
sha256 = "04yri911rj9j19qqqn6m82266fl05pz98inasni0vxr1cf1gdgv9";
|
||
}
|
||
</programlisting>
|
||
</para>
|
||
</listitem>
|
||
</itemizedlist>
|
||
</para>
|
||
</section>
|
||
|
||
<section xml:id="sec-patches"><title>Patches</title>
|
||
<para>Only patches that are unique to <literal>nixpkgs</literal> should be
|
||
included in <literal>nixpkgs</literal> source.</para>
|
||
<para>Patches available online should be retrieved using
|
||
<literal>fetchpatch</literal>.</para>
|
||
<para>
|
||
<programlisting>
|
||
patches = [
|
||
(fetchpatch {
|
||
name = "fix-check-for-using-shared-freetype-lib.patch";
|
||
url = "http://git.ghostscript.com/?p=ghostpdl.git;a=patch;h=8f5d285";
|
||
sha256 = "1f0k043rng7f0rfl9hhb89qzvvksqmkrikmm38p61yfx51l325xr";
|
||
})
|
||
];
|
||
</programlisting>
|
||
</para>
|
||
</section>
|
||
</chapter>
|