conversions were done using https://github.com/pennae/nix-doc-munge
using (probably) rev f34e145 running
nix-doc-munge nixos/**/*.nix
nix-doc-munge --import nixos/**/*.nix
the tool ensures that only changes that could affect the generated
manual *but don't* are committed, other changes require manual review
and are discarded.
the conversion procedure is simple:
- find all things that look like options, ie calls to either `mkOption`
or `lib.mkOption` that take an attrset. remember the attrset as the
option
- for all options, find a `description` attribute who's value is not a
call to `mdDoc` or `lib.mdDoc`
- textually convert the entire value of the attribute to MD with a few
simple regexes (the set from mdize-module.sh)
- if the change produced a change in the manual output, discard
- if the change kept the manual unchanged, add some text to the
description to make sure we've actually found an option. if the
manual changes this time, keep the converted description
this procedure converts 80% of nixos options to markdown. around 2000
options remain to be inspected, but most of those fail the "does not
change the manual output check": currently the MD conversion process
does not faithfully convert docbook tags like <code> and <package>, so
any option using such tags will not be converted at all.
before:
- /var/run/memcached is a bad default for a socket path, since its
parent directory must be writeable by memcached.
- Socket directory was not created by the module itself -> this was
left as a burden to the user?
- Having a static uid with a dynamic user name is not very useful.
after:
- Replace services.memcached.socket by a boolean flag. This simplifies
our code, since we do not have to check if the user specifies a
path with a parent directory that should be owned by memcached
(/run/memcached/memcached.sock -> /run/memcached).
- Remove fixed uid/gid allocation. The only file ever owned by the
daemon is the socket that will be recreated on every start.
Therefore user and group ids do not need to be static.
- only create the memcached user, if the user has not specified a
different one. The major use case for changing option is to allow
existing services (such as php-fpm) opening the local unix socket.
If we would unconditionally create a user that option would be
useless.
Using pkgs.lib on the spine of module evaluation is problematic
because the pkgs argument depends on the result of module
evaluation. To prevent an infinite recursion, pkgs and some of the
modules are evaluated twice, which is inefficient. Using ‘with lib’
prevents this problem.
