lib.modules.doRename: Add doc comments

I don't think these are rendered yet, but this at least provides
the content.

Follow-up to https://github.com/NixOS/nixpkgs/pull/285612
This commit is contained in:
Robert Hensing 2024-02-05 19:22:33 +01:00
parent 29c7665003
commit fe36252019

View file

@ -1256,7 +1256,78 @@ let
(opt.highestPrio or defaultOverridePriority)
(f opt.value);
doRename = { from, to, visible, warn, use, withPriority ? true, condition ? true }:
/*
Return a module that help declares an option that has been renamed.
When a value is defined for the old option, it is forwarded to the `to` option.
*/
doRename = {
# List of strings representing the attribute path of the old option.
from,
# List of strings representing the attribute path of the new option.
to,
# Boolean, whether the old option is to be included in documentation.
visible,
# Whether to warn when a value is defined for the old option.
# NOTE: This requires the NixOS assertions module to be imported, so
# - this generally does not work in submodules
# - this may or may not work outside NixOS
warn,
# A function that is applied to the option value, to form the value
# of the old `from` option.
#
# For example, the identity function can be passed, to return the option value unchanged.
# ```nix
# use = x: x;
# ```
#
# To add a warning, you can pass the partially applied `warn` function.
# ```nix
# use = lib.warn "Obsolete option `${opt.old}' is used. Use `${opt.to}' instead.";
# ```
use,
# Legacy option, enabled by default: whether to preserve the priority of definitions in `old`.
withPriority ? true,
# A boolean that defines the `mkIf` condition for `to`.
# If the condition evaluates to `true`, and the `to` path points into an
# `attrsOf (submodule ...)`, then `doRename` would cause an empty module to
# be created, even if the `from` option is undefined.
# By setting this to an expression that may return `false`, you can inhibit
# this undesired behavior.
#
# Example:
#
# ```nix
# { config, lib, ... }:
# let
# inherit (lib) mkOption mkEnableOption types doRename;
# in
# {
# options = {
#
# # Old service
# services.foo.enable = mkEnableOption "foo";
#
# # New multi-instance service
# services.foos = mkOption {
# type = types.attrsOf (types.submodule …);
# };
# };
# imports = [
# (doRename {
# from = [ "services" "foo" "bar" ];
# to = [ "services" "foos" "" "bar" ];
# visible = true;
# warn = false;
# use = x: x;
# withPriority = true;
# # Only define services.foos."" if needed. (It's not just about `bar`)
# condition = config.services.foo.enable;
# })
# ];
# }
# ```
condition ? true
}:
{ config, options, ... }:
let
fromOpt = getAttrFromPath from options;