nixpkgs/lib/modules.nix

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# NixOS module handling.
let lib = import ./default.nix; in
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with { inherit (builtins) head; };
with import ./trivial.nix;
with import ./lists.nix;
with import ./misc.nix;
with import ./attrsets.nix;
with import ./options.nix;
with import ./properties.nix;
rec {
# Unfortunately this can also be a string.
isPath = x: !(
builtins.isFunction x
|| builtins.isAttrs x
|| builtins.isInt x
|| builtins.isBool x
|| builtins.isList x
);
importIfPath = path:
if isPath path then
import path
else
path;
applyIfFunction = f: arg:
if builtins.isFunction f then
f arg
else
f;
isModule = m:
(m ? config && isAttrs m.config && ! isOption m.config)
|| (m ? options && isAttrs m.options && ! isOption m.options);
# Convert module to a set which has imports / options and config
# attributes.
unifyModuleSyntax = m:
let
delayedModule = delayProperties m;
getImports =
toList (rmProperties (delayedModule.require or []));
getImportedPaths = filter isPath getImports;
getImportedSets = filter (x: !isPath x) getImports;
getConfig =
removeAttrs delayedModule ["require" "key" "imports"];
in
if isModule m then
{ key = "<unknown location>"; } // m
else
{ key = "<unknown location>";
imports = (m.imports or []) ++ getImportedPaths;
config = getConfig;
} // (
if getImportedSets != [] then
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assert length getImportedSets == 1;
{ options = head getImportedSets; }
else
{}
);
unifyOptionModule = {key ? "<unknown location>"}: name: index: m: (args:
let
module = lib.applyIfFunction m args;
key_ = rec {
file = key;
option = name;
number = index;
outPath = key;
};
in if lib.isModule module then
{ key = key_; } // module
else
{ key = key_; options = module; }
);
moduleClosure = initModules: args:
let
moduleImport = origin: index: m:
let m' = applyIfFunction (importIfPath m) args;
in (unifyModuleSyntax m') // {
# used by generic closure to avoid duplicated imports.
key =
if isPath m then m
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else m'.key or (newModuleName origin index);
};
getImports = m: m.imports or [];
newModuleName = origin: index:
"${origin.key}:<import-${toString index}>";
topLevel = {
key = "<top-level>";
};
in
(lazyGenericClosure {
startSet = imap (moduleImport topLevel) initModules;
operator = m: imap (moduleImport m) (getImports m);
});
moduleApply = funs: module:
lib.mapAttrs (name: value:
if builtins.hasAttr name funs then
let fun = lib.getAttr name funs; in
fun value
else
value
) module;
# Handle mkMerge function left behind after a delay property.
moduleFlattenMerge = module:
if module ? config &&
isProperty module.config &&
isMerge module.config.property
then
(map (cfg: { key = module.key; config = cfg; }) module.config.content)
++ [ (module // { config = {}; }) ]
else
[ module ];
# Handle mkMerge attributes which are left behind by previous delay
# properties and convert them into a list of modules. Delay properties
# inside the config attribute of a module and create a second module if a
# mkMerge attribute was left behind.
#
# Module -> [ Module ]
delayModule = module:
map (moduleApply { config = delayProperties; }) (moduleFlattenMerge module);
evalDefinitions = opt: values:
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if opt.type.delayOnGlobalEval or false then
map (delayPropertiesWithIter opt.type.iter opt.name)
(evalLocalProperties values)
else
evalProperties values;
selectModule = name: m:
{ inherit (m) key;
} // (
if m ? options && builtins.hasAttr name m.options then
{ options = lib.getAttr name m.options; }
else {}
) // (
if m ? config && builtins.hasAttr name m.config then
{ config = lib.getAttr name m.config; }
else {}
);
filterModules = name: modules:
filter (m: m ? config || m ? options) (
map (selectModule name) modules
);
modulesNames = modules:
lib.concatMap (m: []
++ optionals (m ? options) (lib.attrNames m.options)
++ optionals (m ? config) (lib.attrNames m.config)
) modules;
moduleZip = funs: modules:
lib.mapAttrs (name: fun:
fun (catAttrs name modules)
) funs;
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moduleMerge = path: modules_:
let
addName = name:
if path == "" then name else path + "." + name;
modules = concatLists (map delayModule modules_);
modulesOf = name: filterModules name modules;
declarationsOf = name: filter (m: m ? options) (modulesOf name);
definitionsOf = name: filter (m: m ? config ) (modulesOf name);
recurseInto = name:
moduleMerge (addName name) (modulesOf name);
recurseForOption = name: modules: args:
moduleMerge name (
moduleClosure modules args
);
errorSource = modules:
"The error may come from the following files:\n" + (
lib.concatStringsSep "\n" (
map (m:
if m ? key then toString m.key else "<unknown location>"
) modules
)
);
eol = "\n";
allNames = modulesNames modules;
getResults = m:
let fetchResult = s: mapAttrs (n: v: v.result) s; in {
options = fetchResult m.options;
config = fetchResult m.config;
};
endRecursion = { options = {}; config = {}; };
in if modules == [] then endRecursion else
getResults (fix (crossResults: moduleZip {
options = lib.zipWithNames allNames (name: values: rec {
config = lib.getAttr name crossResults.config;
declarations = declarationsOf name;
declarationSources =
map (m: {
source = m.key;
}) declarations;
hasOptions = values != [];
isOption = any lib.isOption values;
decls = # add location to sub-module options.
map (m:
mapSubOptions
(unifyOptionModule {inherit (m) key;} name)
m.options
) declarations;
decl =
lib.addErrorContext "${eol
}while enhancing option `${addName name}':${eol
}${errorSource declarations}${eol
}" (
addOptionMakeUp
{ name = addName name; recurseInto = recurseForOption; }
(mergeOptionDecls decls)
);
value = decl // (with config; {
inherit (config) isNotDefined;
isDefined = ! isNotDefined;
declarations = declarationSources;
definitions = definitionSources;
config = strictResult;
});
recurse = (recurseInto name).options;
result =
if isOption then value
else if !hasOptions then {}
else if all isAttrs values then recurse
else
throw "${eol
}Unexpected type where option declarations are expected.${eol
}${errorSource declarations}${eol
}";
});
config = lib.zipWithNames allNames (name: values_: rec {
option = lib.getAttr name crossResults.options;
definitions = definitionsOf name;
definitionSources =
map (m: {
source = m.key;
value = m.config;
}) definitions;
values = values_ ++
optionals (option.isOption && option.decl ? extraConfigs)
option.decl.extraConfigs;
defs = evalDefinitions option.decl values;
isNotDefined = defs == [];
value =
lib.addErrorContext "${eol
}while evaluating the option `${addName name}':${eol
}${errorSource (modulesOf name)}${eol
}" (
let opt = option.decl; in
opt.apply (
if isNotDefined then
opt.default or (throw "Option `${addName name}' not defined and does not have a default value.")
else opt.merge defs
)
);
strictResult = builtins.tryEval (builtins.toXML value);
recurse = (recurseInto name).config;
configIsAnOption = v: isOption (rmProperties v);
errConfigIsAnOption =
let badModules = filter (m: configIsAnOption m.config) definitions; in
"${eol
}Option ${addName name} is defined in the configuration section.${eol
}${errorSource badModules}${eol
}";
errDefinedWithoutDeclaration =
let badModules = definitions; in
"${eol
}Option '${addName name}' defined without option declaration.${eol
}${errorSource badModules}${eol
}";
result =
if option.isOption then value
else if !option.hasOptions then throw errDefinedWithoutDeclaration
else if any configIsAnOption values then throw errConfigIsAnOption
else if all isAttrs values then recurse
# plain value during the traversal
else throw errDefinedWithoutDeclaration;
});
} modules));
fixMergeModules = initModules: {...}@args:
lib.fix (result:
# This trick avoids an infinite loop because names of attribute
# are know and it is not required to evaluate the result of
# moduleMerge to know which attributes are present as arguments.
let module = { inherit (result) options config; }; in
moduleMerge "" (
moduleClosure initModules (module // args)
)
);
# Visit all definitions to raise errors related to undeclared options.
checkModule = path: {config, options, ...}@m:
let
eol = "\n";
addName = name:
if path == "" then name else path + "." + name;
in
if lib.isOption options then
if options ? options then
options.type.fold
(cfg: res: res && checkModule (options.type.docPath path) cfg._args)
true config
else
true
else if isAttrs options && lib.attrNames m.options != [] then
all (name:
lib.addErrorContext "${eol
}while checking the attribute `${addName name}':${eol
}" (checkModule (addName name) (selectModule name m))
) (lib.attrNames m.config)
else
builtins.trace "try to evaluate config ${lib.showVal config}."
false;
}