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nixpkgs/nixos/modules/misc/meta.nix
pennae fc614c37c6 nixos/documentation: split options doc build
most modules can be evaluated for their documentation in a very
restricted environment that doesn't include all of nixpkgs. this
evaluation can then be cached and reused for subsequent builds, merging
only documentation that has changed into the cached set. since nixos
ships with a large number of modules of which only a few are used in any
given config this can save evaluation a huge percentage of nixos
options available in any given config.

in tests of this caching, despite having to copy most of nixos/, saves
about 80% of the time needed to build the system manual, or about two
second on the machine used for testing. build time for a full system
config shrank from 9.4s to 7.4s, while turning documentation off
entirely shortened the build to 7.1s.
2022-01-02 19:46:13 +01:00

77 lines
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Nix

{ lib, ... }:
with lib;
let
maintainer = mkOptionType {
name = "maintainer";
check = email: elem email (attrValues lib.maintainers);
merge = loc: defs: listToAttrs (singleton (nameValuePair (last defs).file (last defs).value));
};
listOfMaintainers = types.listOf maintainer // {
# Returns list of
# { "module-file" = [
# "maintainer1 <first@nixos.org>"
# "maintainer2 <second@nixos.org>" ];
# }
merge = loc: defs:
zipAttrs
(flatten (imap1 (n: def: imap1 (m: def':
maintainer.merge (loc ++ ["[${toString n}-${toString m}]"])
[{ inherit (def) file; value = def'; }]) def.value) defs));
};
docFile = types.path // {
# Returns tuples of
# { file = "module location"; value = <path/to/doc.xml>; }
merge = loc: defs: defs;
};
in
{
options = {
meta = {
maintainers = mkOption {
type = listOfMaintainers;
internal = true;
default = [];
example = literalExpression ''[ lib.maintainers.all ]'';
description = ''
List of maintainers of each module. This option should be defined at
most once per module.
'';
};
doc = mkOption {
type = docFile;
internal = true;
example = "./meta.chapter.xml";
description = ''
Documentation prologue for the set of options of each module. This
option should be defined at most once per module.
'';
};
buildDocsInSandbox = mkOption {
type = types.bool // {
merge = loc: defs: defs;
};
internal = true;
default = true;
description = ''
Whether to include this module in the split options doc build.
Disable if the module references `config`, `pkgs` or other module
arguments that cannot be evaluated as constants.
This option should be defined at most once per module.
'';
};
};
};
meta.maintainers = singleton lib.maintainers.pierron;
}