lib.types: add types.option (#499945) (8d4e3729) · Commits · nix / nixpkgs

lib/tests/modules.sh

+4 −0

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		@@ -717,6 +717,10 @@ checkConfigError 'In module .*/options-type-error-configuration.nix: expected an
		# Check that that merging of option collisions doesn't depend on type being set
		checkConfigError 'The option .group..would be a parent of the following options, but its type .<no description>. does not support nested options.\n\s- option.s. with prefix .group.enable..*' config.group.enable ./merge-typeless-option.nix

		# types.optionDeclaration
		checkConfigOutput '^10$' config.anOption ./option.nix
		checkConfigError 'A definition for option .aBadOptionDef. is not of type .option declaration.' config.aBadOptionDef ./option.nix

		# Test that types.optionType merges types correctly
		checkConfigOutput '^10$' config.theOption.int ./optionTypeMerging.nix
		checkConfigOutput '^"hello"$' config.theOption.str ./optionTypeMerging.nix

0 → 100644

+27 −0

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		{
		config,
		lib,
		options,
		...
		}:
		{
		options = {
		theOption = lib.mkOption {
		type = lib.types.optionDeclaration;
		};
		anOption = config.theOption;
		aBadOptionDef = lib.mkOption {
		type = lib.types.optionDeclaration;
		description = ''
		This option is perfectly fine, but will have a bad definition.
		'';
		};
		};
		config = {
		theOption = lib.mkOption {
		type = lib.types.int;
		};
		anOption = 10;
		aBadOptionDef = options.theOption; # Not a declaration
		};
		}

+7 −0

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		@@ -1180,6 +1180,13 @@ rec {
		};
		};

		optionDeclaration = mkOptionType {
		name = "optionDeclaration";
		description = "option declaration";
		descriptionClass = "noun";
		check = opt: isType "option" opt && !(opt ? value);
		};

		# The type of a type!
		optionType = mkOptionType {
		name = "optionType";

+16 −0

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		@@ -137,6 +137,22 @@ Users must still be careful about how they reference these paths.
		multiple option definitions are correctly merged together. The main use
		case is as the type of the `_module.freeformType` option.

		`types.optionDeclaration`

		: The type of a module system option declaration, as created by `lib.mkOption`.
		This allows an option to hold another option declaration as its value, which
		can then be spliced into a module's `options` attrset. Note that this only
		accepts option declarations, not evaluated options (i.e. options that have
		been processed by `evalModules` and have a `value` field).

		::: {.warning}
		Use of this type is a form of metaprogramming that makes modules harder
		to reason about, since options and their types become dynamic values
		rather than statically declared structure. Prefer conventional module
		patterns where possible, and only reach for `types.optionDeclaration` when the
		added complexity is justified.
		:::

		`types.attrs`

		: A free-form attribute set.