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Revert "nixos/doc: re-format"

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This reverts commit ea6e8775bd. The new
format is not an improvement.
This commit is contained in:
Eelco Dolstra
2019-09-19 19:17:30 +02:00
parent db3d31b903
commit b0ccd6dd16
124 changed files with 5709 additions and 1940 deletions
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nixos/doc/manual/development/assertions.xml
+15 -3
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@@ -6,11 +6,18 @@
<title>Warnings and Assertions</title>
<para>
When configuration problems are detectable in a module, it is a good idea to write an assertion or warning. Doing so provides clear feedback to the user and prevents errors after the build.
When configuration problems are detectable in a module, it is a good idea to
write an assertion or warning. Doing so provides clear feedback to the user
and prevents errors after the build.
</para>
<para>
Although Nix has the <literal>abort</literal> and <literal>builtins.trace</literal> <link xlink:href="https://nixos.org/nix/manual/#ssec-builtins">functions</link> to perform such tasks, they are not ideally suited for NixOS modules. Instead of these functions, you can declare your warnings and assertions using the NixOS module system.
Although Nix has the <literal>abort</literal> and
<literal>builtins.trace</literal>
<link xlink:href="https://nixos.org/nix/manual/#ssec-builtins">functions</link>
to perform such tasks, they are not ideally suited for NixOS modules. Instead
of these functions, you can declare your warnings and assertions using the
NixOS module system.
</para>
<section xml:id="sec-assertions-warnings">
@@ -41,7 +48,12 @@
<title>Assertions</title>
<para>
This example, extracted from the <link xlink:href="https://github.com/NixOS/nixpkgs/blob/release-17.09/nixos/modules/services/logging/syslogd.nix"> <literal>syslogd</literal> module </link> shows how to use <literal>assertions</literal>. Since there can only be one active syslog daemon at a time, an assertion is useful to prevent such a broken system from being built.
This example, extracted from the
<link xlink:href="https://github.com/NixOS/nixpkgs/blob/release-17.09/nixos/modules/services/logging/syslogd.nix">
<literal>syslogd</literal> module </link> shows how to use
<literal>assertions</literal>. Since there can only be one active syslog
daemon at a time, an assertion is useful to prevent such a broken system
from being built.
</para>
<programlisting>