nixpkgs/lib/customisation.nix
Adam Joseph a1fdbae706 lib.customisation: add uncurried form of makeScopeWithSplicing
Deeply-curried functions are pretty error-prone in untyped languages
like Nix.  This is a particularly bad case because
`top-level/splice.nix` *also* declares a makeScopeWithSplicing, but
it takes *two fewer arguments*.

Let's add a version that uses attrset-passing form, to provide some
minimal level of sanity-checking.

This also provides defaults for keep and extra (these are often
unneeded by the user).
2023-08-14 02:50:32 +03:00

323 lines
13 KiB
Nix

{ lib }:
rec {
/* `overrideDerivation drv f` takes a derivation (i.e., the result
of a call to the builtin function `derivation`) and returns a new
derivation in which the attributes of the original are overridden
according to the function `f`. The function `f` is called with
the original derivation attributes.
`overrideDerivation` allows certain "ad-hoc" customisation
scenarios (e.g. in ~/.config/nixpkgs/config.nix). For instance,
if you want to "patch" the derivation returned by a package
function in Nixpkgs to build another version than what the
function itself provides, you can do something like this:
mySed = overrideDerivation pkgs.gnused (oldAttrs: {
name = "sed-4.2.2-pre";
src = fetchurl {
url = ftp://alpha.gnu.org/gnu/sed/sed-4.2.2-pre.tar.bz2;
sha256 = "11nq06d131y4wmf3drm0yk502d2xc6n5qy82cg88rb9nqd2lj41k";
};
patches = [];
});
For another application, see build-support/vm, where this
function is used to build arbitrary derivations inside a QEMU
virtual machine.
Note that in order to preserve evaluation errors, the new derivation's
outPath depends on the old one's, which means that this function cannot
be used in circular situations when the old derivation also depends on the
new one.
You should in general prefer `drv.overrideAttrs` over this function;
see the nixpkgs manual for more information on overriding.
*/
overrideDerivation = drv: f:
let
newDrv = derivation (drv.drvAttrs // (f drv));
in lib.flip (extendDerivation (builtins.seq drv.drvPath true)) newDrv (
{ meta = drv.meta or {};
passthru = if drv ? passthru then drv.passthru else {};
}
//
(drv.passthru or {})
//
lib.optionalAttrs (drv ? __spliced) {
__spliced = {} // (lib.mapAttrs (_: sDrv: overrideDerivation sDrv f) drv.__spliced);
});
/* `makeOverridable` takes a function from attribute set to attribute set and
injects `override` attribute which can be used to override arguments of
the function.
nix-repl> x = {a, b}: { result = a + b; }
nix-repl> y = lib.makeOverridable x { a = 1; b = 2; }
nix-repl> y
{ override = «lambda»; overrideDerivation = «lambda»; result = 3; }
nix-repl> y.override { a = 10; }
{ override = «lambda»; overrideDerivation = «lambda»; result = 12; }
Please refer to "Nixpkgs Contributors Guide" section
"<pkg>.overrideDerivation" to learn about `overrideDerivation` and caveats
related to its use.
*/
makeOverridable = f: origArgs:
let
result = f origArgs;
# Creates a functor with the same arguments as f
copyArgs = g: lib.setFunctionArgs g (lib.functionArgs f);
# Changes the original arguments with (potentially a function that returns) a set of new attributes
overrideWith = newArgs: origArgs // (if lib.isFunction newArgs then newArgs origArgs else newArgs);
# Re-call the function but with different arguments
overrideArgs = copyArgs (newArgs: makeOverridable f (overrideWith newArgs));
# Change the result of the function call by applying g to it
overrideResult = g: makeOverridable (copyArgs (args: g (f args))) origArgs;
in
if builtins.isAttrs result then
result // {
override = overrideArgs;
overrideDerivation = fdrv: overrideResult (x: overrideDerivation x fdrv);
${if result ? overrideAttrs then "overrideAttrs" else null} = fdrv:
overrideResult (x: x.overrideAttrs fdrv);
}
else if lib.isFunction result then
# Transform the result into a functor while propagating its arguments
lib.setFunctionArgs result (lib.functionArgs result) // {
override = overrideArgs;
}
else result;
/* Call the package function in the file `fn` with the required
arguments automatically. The function is called with the
arguments `args`, but any missing arguments are obtained from
`autoArgs`. This function is intended to be partially
parameterised, e.g.,
callPackage = callPackageWith pkgs;
pkgs = {
libfoo = callPackage ./foo.nix { };
libbar = callPackage ./bar.nix { };
};
If the `libbar` function expects an argument named `libfoo`, it is
automatically passed as an argument. Overrides or missing
arguments can be supplied in `args`, e.g.
libbar = callPackage ./bar.nix {
libfoo = null;
enableX11 = true;
};
*/
callPackageWith = autoArgs: fn: args:
let
f = if lib.isFunction fn then fn else import fn;
fargs = lib.functionArgs f;
# All arguments that will be passed to the function
# This includes automatic ones and ones passed explicitly
allArgs = builtins.intersectAttrs fargs autoArgs // args;
# A list of argument names that the function requires, but
# wouldn't be passed to it
missingArgs = lib.attrNames
# Filter out arguments that have a default value
(lib.filterAttrs (name: value: ! value)
# Filter out arguments that would be passed
(removeAttrs fargs (lib.attrNames allArgs)));
# Get a list of suggested argument names for a given missing one
getSuggestions = arg: lib.pipe (autoArgs // args) [
lib.attrNames
# Only use ones that are at most 2 edits away. While mork would work,
# levenshteinAtMost is only fast for 2 or less.
(lib.filter (lib.strings.levenshteinAtMost 2 arg))
# Put strings with shorter distance first
(lib.sort (x: y: lib.strings.levenshtein x arg < lib.strings.levenshtein y arg))
# Only take the first couple results
(lib.take 3)
# Quote all entries
(map (x: "\"" + x + "\""))
];
prettySuggestions = suggestions:
if suggestions == [] then ""
else if lib.length suggestions == 1 then ", did you mean ${lib.elemAt suggestions 0}?"
else ", did you mean ${lib.concatStringsSep ", " (lib.init suggestions)} or ${lib.last suggestions}?";
errorForArg = arg:
let
loc = builtins.unsafeGetAttrPos arg fargs;
# loc' can be removed once lib/minver.nix is >2.3.4, since that includes
# https://github.com/NixOS/nix/pull/3468 which makes loc be non-null
loc' = if loc != null then loc.file + ":" + toString loc.line
else if ! lib.isFunction fn then
toString fn + lib.optionalString (lib.sources.pathIsDirectory fn) "/default.nix"
else "<unknown location>";
in "Function called without required argument \"${arg}\" at "
+ "${loc'}${prettySuggestions (getSuggestions arg)}";
# Only show the error for the first missing argument
error = errorForArg (lib.head missingArgs);
in if missingArgs == [] then makeOverridable f allArgs else abort error;
/* Like callPackage, but for a function that returns an attribute
set of derivations. The override function is added to the
individual attributes. */
callPackagesWith = autoArgs: fn: args:
let
f = if lib.isFunction fn then fn else import fn;
auto = builtins.intersectAttrs (lib.functionArgs f) autoArgs;
origArgs = auto // args;
pkgs = f origArgs;
mkAttrOverridable = name: _: makeOverridable (newArgs: (f newArgs).${name}) origArgs;
in
if lib.isDerivation pkgs then throw
("function `callPackages` was called on a *single* derivation "
+ ''"${pkgs.name or "<unknown-name>"}";''
+ " did you mean to use `callPackage` instead?")
else lib.mapAttrs mkAttrOverridable pkgs;
/* Add attributes to each output of a derivation without changing
the derivation itself and check a given condition when evaluating. */
extendDerivation = condition: passthru: drv:
let
outputs = drv.outputs or [ "out" ];
commonAttrs = drv // (builtins.listToAttrs outputsList) //
({ all = map (x: x.value) outputsList; }) // passthru;
outputToAttrListElement = outputName:
{ name = outputName;
value = commonAttrs // {
inherit (drv.${outputName}) type outputName;
outputSpecified = true;
drvPath = assert condition; drv.${outputName}.drvPath;
outPath = assert condition; drv.${outputName}.outPath;
} //
# TODO: give the derivation control over the outputs.
# `overrideAttrs` may not be the only attribute that needs
# updating when switching outputs.
lib.optionalAttrs (passthru?overrideAttrs) {
# TODO: also add overrideAttrs when overrideAttrs is not custom, e.g. when not splicing.
overrideAttrs = f: (passthru.overrideAttrs f).${outputName};
};
};
outputsList = map outputToAttrListElement outputs;
in commonAttrs // {
drvPath = assert condition; drv.drvPath;
outPath = assert condition; drv.outPath;
};
/* Strip a derivation of all non-essential attributes, returning
only those needed by hydra-eval-jobs. Also strictly evaluate the
result to ensure that there are no thunks kept alive to prevent
garbage collection. */
hydraJob = drv:
let
outputs = drv.outputs or ["out"];
commonAttrs =
{ inherit (drv) name system meta; inherit outputs; }
// lib.optionalAttrs (drv._hydraAggregate or false) {
_hydraAggregate = true;
constituents = map hydraJob (lib.flatten drv.constituents);
}
// (lib.listToAttrs outputsList);
makeOutput = outputName:
let output = drv.${outputName}; in
{ name = outputName;
value = commonAttrs // {
outPath = output.outPath;
drvPath = output.drvPath;
type = "derivation";
inherit outputName;
};
};
outputsList = map makeOutput outputs;
drv' = (lib.head outputsList).value;
in if drv == null then null else
lib.deepSeq drv' drv';
/* Make a set of packages with a common scope. All packages called
with the provided `callPackage` will be evaluated with the same
arguments. Any package in the set may depend on any other. The
`overrideScope'` function allows subsequent modification of the package
set in a consistent way, i.e. all packages in the set will be
called with the overridden packages. The package sets may be
hierarchical: the packages in the set are called with the scope
provided by `newScope` and the set provides a `newScope` attribute
which can form the parent scope for later package sets. */
makeScope = newScope: f:
let self = f self // {
newScope = scope: newScope (self // scope);
callPackage = self.newScope {};
overrideScope = g: lib.warn
"`overrideScope` (from `lib.makeScope`) is deprecated. Do `overrideScope' (self: super: { })` instead of `overrideScope (super: self: { })`. All other overrides have the parameters in that order, including other definitions of `overrideScope`. This was the only definition violating the pattern."
(makeScope newScope (lib.fixedPoints.extends (lib.flip g) f));
overrideScope' = g: makeScope newScope (lib.fixedPoints.extends g f);
packages = f;
};
in self;
/* backward compatibility with old uncurried form; deprecated */
makeScopeWithSplicing =
splicePackages: newScope: otherSplices: keep: extra: f:
makeScopeWithSplicing' {
inherit splicePackages newScope otherSplices keep extra f;
};
/* Like the above, but aims to support cross compilation. It's still ugly, but
hopefully it helps a little bit. */
makeScopeWithSplicing' =
{ splicePackages
, newScope
}:
{ otherSplices
, keep ? (_self: {})
, extra ? (_spliced0: {})
, f
}:
let
spliced0 = splicePackages {
pkgsBuildBuild = otherSplices.selfBuildBuild;
pkgsBuildHost = otherSplices.selfBuildHost;
pkgsBuildTarget = otherSplices.selfBuildTarget;
pkgsHostHost = otherSplices.selfHostHost;
pkgsHostTarget = self; # Not `otherSplices.selfHostTarget`;
pkgsTargetTarget = otherSplices.selfTargetTarget;
};
spliced = extra spliced0 // spliced0 // keep self;
self = f self // {
newScope = scope: newScope (spliced // scope);
callPackage = newScope spliced; # == self.newScope {};
# N.B. the other stages of the package set spliced in are *not*
# overridden.
overrideScope = g: (makeScopeWithSplicing'
{ inherit splicePackages newScope; }
{ inherit otherSplices keep extra;
f = lib.fixedPoints.extends g f;
});
packages = f;
};
in self;
}