This brings back the ability to e.g. configure sane-airscan with
`environment.etc."sane.d/airscan.conf".text = ...`.
(AFAICT, sane-airscan loads all config files it finds, so it'll first
load the one from the nixos hardware.sane.* configuration, then the user
specified one in /etc/sane.d/airscan.conf.)
Fixes: 4fbec87a5b ("nixos/sane: point env vars to /etc for quick reload")
Fixes https://github.com/NixOS/nixpkgs/issues/207262
It's a very useful backend (that probably should be enabled by default,
like on Ubuntu), let's start by making it easier to discover.
Ref https://github.com/NixOS/nixpkgs/issues/28406.
Point $SANE_CONFIG_DIR and $LD_LIBRARY_PATH to symlinks in /etc, instead
of directly to nix store paths, so that activating a new configuration
takes effect immediately, instead of requiring users to re-login.
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.
Whenever I try to scan from another computer it has to establish >2
connections in order to succeed. With the connections being limited to 1
I can not scan any document.
This is also what other distributions ([Debian], [ArchLinux], …) have
done in one way or another.
[Debian]: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=850649#5
[ArchLinux]: no limit: 99cba454bb/trunk/saned.socket (L4)
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.
