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.
Back in 2013, update-mime-database started using fdatasync() to write out
its changes after processing each file in /share/mime, with the reasoning
that a corrupted database from an interruption midway would be
problematic for applications[1]. Unfortunately, this caused a
significant regression in the time required to run update-mime-database:
commonly from under a second to half a minute or more.
This delay affects the time required to build system-path on NixOS, when
xdg.mime.enable is true (the default). For example, on one of my systems
system-path builds in ~48 seconds, 45 of which are update-mime-database.
This makes rapidly building new system configurations not fun.
This commit disables the calls to fdatasync(). update-mime-database
checks an environment variable, PKGSYSTEM_ENABLE_FSYNC, to determine
whether it should sync, and we can set this to false. system-path
already only has whatever filesystem commit guarantees that the Nix
builder provides. Furthermore, there is no risk of a failed MIME
database update messing up existing packages, because this is Nix.
(This issue was also reported at and discussed by Debian, Red Hat, and
Gentoo at least.)
[1] https://bugs.freedesktop.org/show_bug.cgi?id=70366
For update-mime-database to work, you must have to have some mime
packages installed. In some DEs like XFCE this is not guaranteed to
happen. In that case just skip the update-mime-database call.
Fixes#46162
