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nixpkgs/lib/types.nix
Drew Hess 370efefd8c
Replace short URL from #63103 with full URL.
The error message is already helpfully verbose, so there's little
reason to shorten the informational URL.
2020-01-15 13:47:49 +00:00

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# Definitions related to run-time type checking. Used in particular
# to type-check NixOS configurations.
{ lib }:
with lib.lists;
with lib.attrsets;
with lib.options;
with lib.trivial;
with lib.strings;
let
inherit (lib.modules) mergeDefinitions;
outer_types =
rec {
isType = type: x: (x._type or "") == type;
setType = typeName: value: value // {
_type = typeName;
};
# Default type merging function
# takes two type functors and return the merged type
defaultTypeMerge = f: f':
let wrapped = f.wrapped.typeMerge f'.wrapped.functor;
payload = f.binOp f.payload f'.payload;
in
# cannot merge different types
if f.name != f'.name
then null
# simple types
else if (f.wrapped == null && f'.wrapped == null)
&& (f.payload == null && f'.payload == null)
then f.type
# composed types
else if (f.wrapped != null && f'.wrapped != null) && (wrapped != null)
then f.type wrapped
# value types
else if (f.payload != null && f'.payload != null) && (payload != null)
then f.type payload
else null;
# Default type functor
defaultFunctor = name: {
inherit name;
type = types.${name} or null;
wrapped = null;
payload = null;
binOp = a: b: null;
};
isOptionType = isType "option-type";
mkOptionType =
{ # Human-readable representation of the type, should be equivalent to
# the type function name.
name
, # Description of the type, defined recursively by embedding the wrapped type if any.
description ? null
, # Function applied to each definition that should return true if
# its type-correct, false otherwise.
check ? (x: true)
, # Merge a list of definitions together into a single value.
# This function is called with two arguments: the location of
# the option in the configuration as a list of strings
# (e.g. ["boot" "loader "grub" "enable"]), and a list of
# definition values and locations (e.g. [ { file = "/foo.nix";
# value = 1; } { file = "/bar.nix"; value = 2 } ]).
merge ? mergeDefaultOption
, # Whether this type has a value representing nothingness. If it does,
# this should be a value of the form { value = <the nothing value>; }
# If it doesn't, this should be {}
# This may be used when a value is required for `mkIf false`. This allows the extra laziness in e.g. `lazyAttrsOf`.
emptyValue ? {}
, # Return a flat list of sub-options. Used to generate
# documentation.
getSubOptions ? prefix: {}
, # List of modules if any, or null if none.
getSubModules ? null
, # Function for building the same option type with a different list of
# modules.
substSubModules ? m: null
, # Function that merge type declarations.
# internal, takes a functor as argument and returns the merged type.
# returning null means the type is not mergeable
typeMerge ? defaultTypeMerge functor
, # The type functor.
# internal, representation of the type as an attribute set.
# name: name of the type
# type: type function.
# wrapped: the type wrapped in case of compound types.
# payload: values of the type, two payloads of the same type must be
# combinable with the binOp binary operation.
# binOp: binary operation that merge two payloads of the same type.
functor ? defaultFunctor name
}:
{ _type = "option-type";
inherit name check merge emptyValue getSubOptions getSubModules substSubModules typeMerge functor;
description = if description == null then name else description;
};
# When adding new types don't forget to document them in
# nixos/doc/manual/development/option-types.xml!
types = rec {
unspecified = mkOptionType {
name = "unspecified";
};
bool = mkOptionType {
name = "bool";
description = "boolean";
check = isBool;
merge = mergeEqualOption;
};
int = mkOptionType {
name = "int";
description = "signed integer";
check = isInt;
merge = mergeEqualOption;
};
# Specialized subdomains of int
ints =
let
betweenDesc = lowest: highest:
"${toString lowest} and ${toString highest} (both inclusive)";
between = lowest: highest:
assert lib.assertMsg (lowest <= highest)
"ints.between: lowest must be smaller than highest";
addCheck int (x: x >= lowest && x <= highest) // {
name = "intBetween";
description = "integer between ${betweenDesc lowest highest}";
};
ign = lowest: highest: name: docStart:
between lowest highest // {
inherit name;
description = docStart + "; between ${betweenDesc lowest highest}";
};
unsign = bit: range: ign 0 (range - 1)
"unsignedInt${toString bit}" "${toString bit} bit unsigned integer";
sign = bit: range: ign (0 - (range / 2)) (range / 2 - 1)
"signedInt${toString bit}" "${toString bit} bit signed integer";
in {
/* An int with a fixed range.
*
* Example:
* (ints.between 0 100).check (-1)
* => false
* (ints.between 0 100).check (101)
* => false
* (ints.between 0 0).check 0
* => true
*/
inherit between;
unsigned = addCheck types.int (x: x >= 0) // {
name = "unsignedInt";
description = "unsigned integer, meaning >=0";
};
positive = addCheck types.int (x: x > 0) // {
name = "positiveInt";
description = "positive integer, meaning >0";
};
u8 = unsign 8 256;
u16 = unsign 16 65536;
# the biggest int a 64-bit Nix accepts is 2^63 - 1 (9223372036854775808), for a 32-bit Nix it is 2^31 - 1 (2147483647)
# the smallest int a 64-bit Nix accepts is -2^63 (-9223372036854775807), for a 32-bit Nix it is -2^31 (-2147483648)
# u32 = unsign 32 4294967296;
# u64 = unsign 64 18446744073709551616;
s8 = sign 8 256;
s16 = sign 16 65536;
# s32 = sign 32 4294967296;
};
# Alias of u16 for a port number
port = ints.u16;
float = mkOptionType {
name = "float";
description = "floating point number";
check = isFloat;
merge = mergeEqualOption;
};
str = mkOptionType {
name = "str";
description = "string";
check = isString;
merge = mergeEqualOption;
};
strMatching = pattern: mkOptionType {
name = "strMatching ${escapeNixString pattern}";
description = "string matching the pattern ${pattern}";
check = x: str.check x && builtins.match pattern x != null;
inherit (str) merge;
};
# Merge multiple definitions by concatenating them (with the given
# separator between the values).
separatedString = sep: mkOptionType rec {
name = "separatedString";
description = if sep == ""
then "Concatenated string" # for types.string.
else "strings concatenated with ${builtins.toJSON sep}"
;
check = isString;
merge = loc: defs: concatStringsSep sep (getValues defs);
functor = (defaultFunctor name) // {
payload = sep;
binOp = sepLhs: sepRhs:
if sepLhs == sepRhs then sepLhs
else null;
};
};
lines = separatedString "\n";
commas = separatedString ",";
envVar = separatedString ":";
# Deprecated; should not be used because it quietly concatenates
# strings, which is usually not what you want.
string = warn "types.string is deprecated because it quietly concatenates strings"
(separatedString "");
attrs = mkOptionType {
name = "attrs";
description = "attribute set";
check = isAttrs;
merge = loc: foldl' (res: def: mergeAttrs res def.value) {};
emptyValue = { value = {}; };
};
# derivation is a reserved keyword.
package = mkOptionType {
name = "package";
check = x: isDerivation x || isStorePath x;
merge = loc: defs:
let res = mergeOneOption loc defs;
in if isDerivation res then res else toDerivation res;
};
shellPackage = package // {
check = x: (package.check x) && (hasAttr "shellPath" x);
};
path = mkOptionType {
name = "path";
check = x: isCoercibleToString x && builtins.substring 0 1 (toString x) == "/";
merge = mergeEqualOption;
};
# drop this in the future:
list = builtins.trace "`types.list` is deprecated; use `types.listOf` instead" types.listOf;
listOf = elemType: mkOptionType rec {
name = "listOf";
description = "list of ${elemType.description}s";
check = isList;
merge = loc: defs:
map (x: x.value) (filter (x: x ? value) (concatLists (imap1 (n: def:
if isList def.value then
imap1 (m: def':
(mergeDefinitions
(loc ++ ["[definition ${toString n}-entry ${toString m}]"])
elemType
[{ inherit (def) file; value = def'; }]
).optionalValue
) def.value
else
throw "The option value `${showOption loc}` in `${def.file}` is not a list.") defs)));
emptyValue = { value = {}; };
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["*"]);
getSubModules = elemType.getSubModules;
substSubModules = m: listOf (elemType.substSubModules m);
functor = (defaultFunctor name) // { wrapped = elemType; };
};
nonEmptyListOf = elemType:
let list = addCheck (types.listOf elemType) (l: l != []);
in list // {
description = "non-empty " + list.description;
# Note: emptyValue is left as is, because another module may define an element.
};
attrsOf = elemType: mkOptionType rec {
name = "attrsOf";
description = "attribute set of ${elemType.description}s";
check = isAttrs;
merge = loc: defs:
mapAttrs (n: v: v.value) (filterAttrs (n: v: v ? value) (zipAttrsWith (name: defs:
(mergeDefinitions (loc ++ [name]) elemType defs).optionalValue
)
# Push down position info.
(map (def: mapAttrs (n: v: { inherit (def) file; value = v; }) def.value) defs)));
emptyValue = { value = {}; };
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name>"]);
getSubModules = elemType.getSubModules;
substSubModules = m: attrsOf (elemType.substSubModules m);
functor = (defaultFunctor name) // { wrapped = elemType; };
};
# A version of attrsOf that's lazy in its values at the expense of
# conditional definitions not working properly. E.g. defining a value with
# `foo.attr = mkIf false 10`, then `foo ? attr == true`, whereas with
# attrsOf it would correctly be `false`. Accessing `foo.attr` would throw an
# error that it's not defined. Use only if conditional definitions don't make sense.
lazyAttrsOf = elemType: mkOptionType rec {
name = "lazyAttrsOf";
description = "lazy attribute set of ${elemType.description}s";
check = isAttrs;
merge = loc: defs:
zipAttrsWith (name: defs:
let merged = mergeDefinitions (loc ++ [name]) elemType defs;
# mergedValue will trigger an appropriate error when accessed
in merged.optionalValue.value or elemType.emptyValue.value or merged.mergedValue
)
# Push down position info.
(map (def: mapAttrs (n: v: { inherit (def) file; value = v; }) def.value) defs);
emptyValue = { value = {}; };
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name>"]);
getSubModules = elemType.getSubModules;
substSubModules = m: lazyAttrsOf (elemType.substSubModules m);
functor = (defaultFunctor name) // { wrapped = elemType; };
};
# List or attribute set of ...
loaOf = elemType:
let
convertAllLists = loc: defs:
let
padWidth = stringLength (toString (length defs));
unnamedPrefix = i: "unnamed-" + fixedWidthNumber padWidth i + ".";
in
imap1 (i: convertIfList loc (unnamedPrefix i)) defs;
convertIfList = loc: unnamedPrefix: def:
if isList def.value then
let
padWidth = stringLength (toString (length def.value));
unnamed = i: unnamedPrefix + fixedWidthNumber padWidth i;
anyString = placeholder "name";
nameAttrs = [
{ path = [ "environment" "etc" ];
name = "target";
}
{ path = [ "containers" anyString "bindMounts" ];
name = "mountPoint";
}
{ path = [ "programs" "ssh" "knownHosts" ];
# hostNames is actually a list so we would need to handle it only when singleton
name = "hostNames";
}
{ path = [ "fileSystems" ];
name = "mountPoint";
}
{ path = [ "boot" "specialFileSystems" ];
name = "mountPoint";
}
{ path = [ "services" "znapzend" "zetup" ];
name = "dataset";
}
{ path = [ "services" "znapzend" "zetup" anyString "destinations" ];
name = "label";
}
{ path = [ "services" "geoclue2" "appConfig" ];
name = "desktopID";
}
];
matched = let
equals = a: b: b == anyString || a == b;
fallback = { name = "name"; };
in findFirst ({ path, ... }: all (v: v == true) (zipListsWith equals loc path)) fallback nameAttrs;
nameAttr = matched.name;
nameValueOld = value:
if isList value then
if length value > 0 then
"[ " + concatMapStringsSep " " escapeNixString value + " ]"
else
"[ ]"
else
escapeNixString value;
nameValueNew = value: unnamed:
if isList value then
if length value > 0 then
head value
else
unnamed
else
value;
res =
{ inherit (def) file;
value = listToAttrs (
imap1 (elemIdx: elem:
{ name = nameValueNew (elem.${nameAttr} or (unnamed elemIdx)) (unnamed elemIdx);
value = elem;
}) def.value);
};
option = concatStringsSep "." loc;
sample = take 3 def.value;
more = lib.optionalString (length def.value > 3) "... ";
list = concatMapStrings (x: ''{ ${nameAttr} = ${nameValueOld (x.${nameAttr} or "unnamed")}; ...} '') sample;
set = concatMapStrings (x: ''${nameValueNew (x.${nameAttr} or "unnamed") "unnamed"} = {...}; '') sample;
msg = ''
In file ${def.file}
a list is being assigned to the option config.${option}.
This will soon be an error as type loaOf is deprecated.
See https://github.com/NixOS/nixpkgs/pull/63103 for more information.
Do
${option} =
{ ${set}${more}}
instead of
${option} =
[ ${list}${more}]
'';
in
lib.warn msg res
else
def;
attrOnly = attrsOf elemType;
in mkOptionType rec {
name = "loaOf";
description = "list or attribute set of ${elemType.description}s";
check = x: isList x || isAttrs x;
merge = loc: defs: attrOnly.merge loc (convertAllLists loc defs);
emptyValue = { value = {}; };
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name?>"]);
getSubModules = elemType.getSubModules;
substSubModules = m: loaOf (elemType.substSubModules m);
functor = (defaultFunctor name) // { wrapped = elemType; };
};
# Value of given type but with no merging (i.e. `uniq list`s are not concatenated).
uniq = elemType: mkOptionType rec {
name = "uniq";
inherit (elemType) description check;
merge = mergeOneOption;
emptyValue = elemType.emptyValue;
getSubOptions = elemType.getSubOptions;
getSubModules = elemType.getSubModules;
substSubModules = m: uniq (elemType.substSubModules m);
functor = (defaultFunctor name) // { wrapped = elemType; };
};
# Null or value of ...
nullOr = elemType: mkOptionType rec {
name = "nullOr";
description = "null or ${elemType.description}";
check = x: x == null || elemType.check x;
merge = loc: defs:
let nrNulls = count (def: def.value == null) defs; in
if nrNulls == length defs then null
else if nrNulls != 0 then
throw "The option `${showOption loc}` is defined both null and not null, in ${showFiles (getFiles defs)}."
else elemType.merge loc defs;
emptyValue = { value = null; };
getSubOptions = elemType.getSubOptions;
getSubModules = elemType.getSubModules;
substSubModules = m: nullOr (elemType.substSubModules m);
functor = (defaultFunctor name) // { wrapped = elemType; };
};
# A submodule (like typed attribute set). See NixOS manual.
submodule = modules: submoduleWith {
shorthandOnlyDefinesConfig = true;
modules = toList modules;
};
submoduleWith =
{ modules
, specialArgs ? {}
, shorthandOnlyDefinesConfig ? false
}@attrs:
let
inherit (lib.modules) evalModules;
coerce = unify: value: if isFunction value
then setFunctionArgs (args: unify (value args)) (functionArgs value)
else unify (if shorthandOnlyDefinesConfig then { config = value; } else value);
allModules = defs: modules ++ imap1 (n: { value, file }:
if isAttrs value || isFunction value then
# Annotate the value with the location of its definition for better error messages
coerce (lib.modules.unifyModuleSyntax file "${toString file}-${toString n}") value
else value
) defs;
in
mkOptionType rec {
name = "submodule";
check = x: isAttrs x || isFunction x || path.check x;
merge = loc: defs:
(evalModules {
modules = allModules defs;
inherit specialArgs;
args.name = last loc;
prefix = loc;
}).config;
emptyValue = { value = {}; };
getSubOptions = prefix: (evalModules
{ inherit modules prefix specialArgs;
# This is a work-around due to the fact that some sub-modules,
# such as the one included in an attribute set, expects a "args"
# attribute to be given to the sub-module. As the option
# evaluation does not have any specific attribute name, we
# provide a default one for the documentation.
#
# This is mandatory as some option declaration might use the
# "name" attribute given as argument of the submodule and use it
# as the default of option declarations.
#
# Using lookalike unicode single angle quotation marks because
# of the docbook transformation the options receive. In all uses
# &gt; and &lt; wouldn't be encoded correctly so the encoded values
# would be used, and use of `<` and `>` would break the XML document.
# It shouldn't cause an issue since this is cosmetic for the manual.
args.name = "name";
}).options;
getSubModules = modules;
substSubModules = m: submoduleWith (attrs // {
modules = m;
});
functor = defaultFunctor name // {
type = types.submoduleWith;
payload = {
modules = modules;
specialArgs = specialArgs;
shorthandOnlyDefinesConfig = shorthandOnlyDefinesConfig;
};
binOp = lhs: rhs: {
modules = lhs.modules ++ rhs.modules;
specialArgs =
let intersecting = builtins.intersectAttrs lhs.specialArgs rhs.specialArgs;
in if intersecting == {}
then lhs.specialArgs // rhs.specialArgs
else throw "A submoduleWith option is declared multiple times with the same specialArgs \"${toString (attrNames intersecting)}\"";
shorthandOnlyDefinesConfig =
if lhs.shorthandOnlyDefinesConfig == rhs.shorthandOnlyDefinesConfig
then lhs.shorthandOnlyDefinesConfig
else throw "A submoduleWith option is declared multiple times with conflicting shorthandOnlyDefinesConfig values";
};
};
};
# A value from a set of allowed ones.
enum = values:
let
show = v:
if builtins.isString v then ''"${v}"''
else if builtins.isInt v then builtins.toString v
else ''<${builtins.typeOf v}>'';
in
mkOptionType rec {
name = "enum";
description = "one of ${concatMapStringsSep ", " show values}";
check = flip elem values;
merge = mergeEqualOption;
functor = (defaultFunctor name) // { payload = values; binOp = a: b: unique (a ++ b); };
};
# Either value of type `t1` or `t2`.
either = t1: t2: mkOptionType rec {
name = "either";
description = "${t1.description} or ${t2.description}";
check = x: t1.check x || t2.check x;
merge = loc: defs:
let
defList = map (d: d.value) defs;
in
if all (x: t1.check x) defList
then t1.merge loc defs
else if all (x: t2.check x) defList
then t2.merge loc defs
else mergeOneOption loc defs;
typeMerge = f':
let mt1 = t1.typeMerge (elemAt f'.wrapped 0).functor;
mt2 = t2.typeMerge (elemAt f'.wrapped 1).functor;
in
if (name == f'.name) && (mt1 != null) && (mt2 != null)
then functor.type mt1 mt2
else null;
functor = (defaultFunctor name) // { wrapped = [ t1 t2 ]; };
};
# Any of the types in the given list
oneOf = ts:
let
head' = if ts == [] then throw "types.oneOf needs to get at least one type in its argument" else head ts;
tail' = tail ts;
in foldl' either head' tail';
# Either value of type `coercedType` or `finalType`, the former is
# converted to `finalType` using `coerceFunc`.
coercedTo = coercedType: coerceFunc: finalType:
assert lib.assertMsg (coercedType.getSubModules == null)
"coercedTo: coercedType must not have submodules (its a ${
coercedType.description})";
mkOptionType rec {
name = "coercedTo";
description = "${finalType.description} or ${coercedType.description} convertible to it";
check = x: (coercedType.check x && finalType.check (coerceFunc x)) || finalType.check x;
merge = loc: defs:
let
coerceVal = val:
if coercedType.check val then coerceFunc val
else val;
in finalType.merge loc (map (def: def // { value = coerceVal def.value; }) defs);
emptyValue = finalType.emptyValue;
getSubOptions = finalType.getSubOptions;
getSubModules = finalType.getSubModules;
substSubModules = m: coercedTo coercedType coerceFunc (finalType.substSubModules m);
typeMerge = t1: t2: null;
functor = (defaultFunctor name) // { wrapped = finalType; };
};
# Obsolete alternative to configOf. It takes its option
# declarations from the options attribute of containing option
# declaration.
optionSet = mkOptionType {
name = builtins.trace "types.optionSet is deprecated; use types.submodule instead" "optionSet";
description = "option set";
};
# Augment the given type with an additional type check function.
addCheck = elemType: check: elemType // { check = x: elemType.check x && check x; };
};
};
in outer_types // outer_types.types