mirror of
https://github.com/NixOS/nixpkgs.git
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a1fdbae706
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).
323 lines
13 KiB
Nix
323 lines
13 KiB
Nix
{ lib }:
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rec {
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/* `overrideDerivation drv f` takes a derivation (i.e., the result
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of a call to the builtin function `derivation`) and returns a new
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derivation in which the attributes of the original are overridden
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according to the function `f`. The function `f` is called with
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the original derivation attributes.
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`overrideDerivation` allows certain "ad-hoc" customisation
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scenarios (e.g. in ~/.config/nixpkgs/config.nix). For instance,
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if you want to "patch" the derivation returned by a package
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function in Nixpkgs to build another version than what the
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function itself provides, you can do something like this:
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mySed = overrideDerivation pkgs.gnused (oldAttrs: {
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name = "sed-4.2.2-pre";
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src = fetchurl {
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url = ftp://alpha.gnu.org/gnu/sed/sed-4.2.2-pre.tar.bz2;
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sha256 = "11nq06d131y4wmf3drm0yk502d2xc6n5qy82cg88rb9nqd2lj41k";
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};
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patches = [];
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});
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For another application, see build-support/vm, where this
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function is used to build arbitrary derivations inside a QEMU
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virtual machine.
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Note that in order to preserve evaluation errors, the new derivation's
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outPath depends on the old one's, which means that this function cannot
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be used in circular situations when the old derivation also depends on the
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new one.
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You should in general prefer `drv.overrideAttrs` over this function;
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see the nixpkgs manual for more information on overriding.
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*/
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overrideDerivation = drv: f:
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let
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newDrv = derivation (drv.drvAttrs // (f drv));
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in lib.flip (extendDerivation (builtins.seq drv.drvPath true)) newDrv (
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{ meta = drv.meta or {};
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passthru = if drv ? passthru then drv.passthru else {};
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}
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//
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(drv.passthru or {})
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//
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lib.optionalAttrs (drv ? __spliced) {
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__spliced = {} // (lib.mapAttrs (_: sDrv: overrideDerivation sDrv f) drv.__spliced);
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});
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/* `makeOverridable` takes a function from attribute set to attribute set and
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injects `override` attribute which can be used to override arguments of
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the function.
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nix-repl> x = {a, b}: { result = a + b; }
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nix-repl> y = lib.makeOverridable x { a = 1; b = 2; }
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nix-repl> y
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{ override = «lambda»; overrideDerivation = «lambda»; result = 3; }
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nix-repl> y.override { a = 10; }
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{ override = «lambda»; overrideDerivation = «lambda»; result = 12; }
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Please refer to "Nixpkgs Contributors Guide" section
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"<pkg>.overrideDerivation" to learn about `overrideDerivation` and caveats
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related to its use.
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*/
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makeOverridable = f: origArgs:
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let
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result = f origArgs;
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# Creates a functor with the same arguments as f
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copyArgs = g: lib.setFunctionArgs g (lib.functionArgs f);
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# Changes the original arguments with (potentially a function that returns) a set of new attributes
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overrideWith = newArgs: origArgs // (if lib.isFunction newArgs then newArgs origArgs else newArgs);
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# Re-call the function but with different arguments
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overrideArgs = copyArgs (newArgs: makeOverridable f (overrideWith newArgs));
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# Change the result of the function call by applying g to it
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overrideResult = g: makeOverridable (copyArgs (args: g (f args))) origArgs;
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in
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if builtins.isAttrs result then
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result // {
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override = overrideArgs;
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overrideDerivation = fdrv: overrideResult (x: overrideDerivation x fdrv);
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${if result ? overrideAttrs then "overrideAttrs" else null} = fdrv:
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overrideResult (x: x.overrideAttrs fdrv);
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}
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else if lib.isFunction result then
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# Transform the result into a functor while propagating its arguments
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lib.setFunctionArgs result (lib.functionArgs result) // {
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override = overrideArgs;
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}
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else result;
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/* Call the package function in the file `fn` with the required
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arguments automatically. The function is called with the
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arguments `args`, but any missing arguments are obtained from
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`autoArgs`. This function is intended to be partially
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parameterised, e.g.,
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callPackage = callPackageWith pkgs;
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pkgs = {
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libfoo = callPackage ./foo.nix { };
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libbar = callPackage ./bar.nix { };
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};
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If the `libbar` function expects an argument named `libfoo`, it is
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automatically passed as an argument. Overrides or missing
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arguments can be supplied in `args`, e.g.
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libbar = callPackage ./bar.nix {
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libfoo = null;
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enableX11 = true;
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};
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*/
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callPackageWith = autoArgs: fn: args:
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let
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f = if lib.isFunction fn then fn else import fn;
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fargs = lib.functionArgs f;
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# All arguments that will be passed to the function
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# This includes automatic ones and ones passed explicitly
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allArgs = builtins.intersectAttrs fargs autoArgs // args;
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# A list of argument names that the function requires, but
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# wouldn't be passed to it
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missingArgs = lib.attrNames
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# Filter out arguments that have a default value
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(lib.filterAttrs (name: value: ! value)
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# Filter out arguments that would be passed
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(removeAttrs fargs (lib.attrNames allArgs)));
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# Get a list of suggested argument names for a given missing one
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getSuggestions = arg: lib.pipe (autoArgs // args) [
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lib.attrNames
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# Only use ones that are at most 2 edits away. While mork would work,
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# levenshteinAtMost is only fast for 2 or less.
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(lib.filter (lib.strings.levenshteinAtMost 2 arg))
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# Put strings with shorter distance first
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(lib.sort (x: y: lib.strings.levenshtein x arg < lib.strings.levenshtein y arg))
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# Only take the first couple results
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(lib.take 3)
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# Quote all entries
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(map (x: "\"" + x + "\""))
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];
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prettySuggestions = suggestions:
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if suggestions == [] then ""
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else if lib.length suggestions == 1 then ", did you mean ${lib.elemAt suggestions 0}?"
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else ", did you mean ${lib.concatStringsSep ", " (lib.init suggestions)} or ${lib.last suggestions}?";
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errorForArg = arg:
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let
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loc = builtins.unsafeGetAttrPos arg fargs;
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# loc' can be removed once lib/minver.nix is >2.3.4, since that includes
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# https://github.com/NixOS/nix/pull/3468 which makes loc be non-null
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loc' = if loc != null then loc.file + ":" + toString loc.line
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else if ! lib.isFunction fn then
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toString fn + lib.optionalString (lib.sources.pathIsDirectory fn) "/default.nix"
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else "<unknown location>";
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in "Function called without required argument \"${arg}\" at "
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+ "${loc'}${prettySuggestions (getSuggestions arg)}";
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# Only show the error for the first missing argument
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error = errorForArg (lib.head missingArgs);
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in if missingArgs == [] then makeOverridable f allArgs else abort error;
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/* Like callPackage, but for a function that returns an attribute
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set of derivations. The override function is added to the
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individual attributes. */
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callPackagesWith = autoArgs: fn: args:
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let
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f = if lib.isFunction fn then fn else import fn;
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auto = builtins.intersectAttrs (lib.functionArgs f) autoArgs;
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origArgs = auto // args;
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pkgs = f origArgs;
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mkAttrOverridable = name: _: makeOverridable (newArgs: (f newArgs).${name}) origArgs;
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in
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if lib.isDerivation pkgs then throw
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("function `callPackages` was called on a *single* derivation "
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+ ''"${pkgs.name or "<unknown-name>"}";''
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+ " did you mean to use `callPackage` instead?")
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else lib.mapAttrs mkAttrOverridable pkgs;
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/* Add attributes to each output of a derivation without changing
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the derivation itself and check a given condition when evaluating. */
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extendDerivation = condition: passthru: drv:
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let
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outputs = drv.outputs or [ "out" ];
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commonAttrs = drv // (builtins.listToAttrs outputsList) //
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({ all = map (x: x.value) outputsList; }) // passthru;
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outputToAttrListElement = outputName:
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{ name = outputName;
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value = commonAttrs // {
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inherit (drv.${outputName}) type outputName;
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outputSpecified = true;
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drvPath = assert condition; drv.${outputName}.drvPath;
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outPath = assert condition; drv.${outputName}.outPath;
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} //
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# TODO: give the derivation control over the outputs.
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# `overrideAttrs` may not be the only attribute that needs
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# updating when switching outputs.
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lib.optionalAttrs (passthru?overrideAttrs) {
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# TODO: also add overrideAttrs when overrideAttrs is not custom, e.g. when not splicing.
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overrideAttrs = f: (passthru.overrideAttrs f).${outputName};
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};
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};
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outputsList = map outputToAttrListElement outputs;
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in commonAttrs // {
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drvPath = assert condition; drv.drvPath;
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outPath = assert condition; drv.outPath;
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};
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/* Strip a derivation of all non-essential attributes, returning
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only those needed by hydra-eval-jobs. Also strictly evaluate the
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result to ensure that there are no thunks kept alive to prevent
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garbage collection. */
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hydraJob = drv:
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let
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outputs = drv.outputs or ["out"];
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commonAttrs =
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{ inherit (drv) name system meta; inherit outputs; }
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// lib.optionalAttrs (drv._hydraAggregate or false) {
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_hydraAggregate = true;
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constituents = map hydraJob (lib.flatten drv.constituents);
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}
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// (lib.listToAttrs outputsList);
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makeOutput = outputName:
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let output = drv.${outputName}; in
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{ name = outputName;
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value = commonAttrs // {
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outPath = output.outPath;
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drvPath = output.drvPath;
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type = "derivation";
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inherit outputName;
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};
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};
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outputsList = map makeOutput outputs;
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drv' = (lib.head outputsList).value;
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in if drv == null then null else
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lib.deepSeq drv' drv';
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/* Make a set of packages with a common scope. All packages called
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with the provided `callPackage` will be evaluated with the same
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arguments. Any package in the set may depend on any other. The
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`overrideScope'` function allows subsequent modification of the package
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set in a consistent way, i.e. all packages in the set will be
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called with the overridden packages. The package sets may be
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hierarchical: the packages in the set are called with the scope
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provided by `newScope` and the set provides a `newScope` attribute
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which can form the parent scope for later package sets. */
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makeScope = newScope: f:
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let self = f self // {
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newScope = scope: newScope (self // scope);
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callPackage = self.newScope {};
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overrideScope = g: lib.warn
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"`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."
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(makeScope newScope (lib.fixedPoints.extends (lib.flip g) f));
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overrideScope' = g: makeScope newScope (lib.fixedPoints.extends g f);
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packages = f;
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};
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in self;
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/* backward compatibility with old uncurried form; deprecated */
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makeScopeWithSplicing =
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splicePackages: newScope: otherSplices: keep: extra: f:
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makeScopeWithSplicing' {
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inherit splicePackages newScope otherSplices keep extra f;
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};
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/* Like the above, but aims to support cross compilation. It's still ugly, but
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hopefully it helps a little bit. */
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makeScopeWithSplicing' =
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{ splicePackages
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, newScope
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}:
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{ otherSplices
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, keep ? (_self: {})
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, extra ? (_spliced0: {})
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, f
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}:
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let
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spliced0 = splicePackages {
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pkgsBuildBuild = otherSplices.selfBuildBuild;
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pkgsBuildHost = otherSplices.selfBuildHost;
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pkgsBuildTarget = otherSplices.selfBuildTarget;
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pkgsHostHost = otherSplices.selfHostHost;
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pkgsHostTarget = self; # Not `otherSplices.selfHostTarget`;
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pkgsTargetTarget = otherSplices.selfTargetTarget;
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};
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spliced = extra spliced0 // spliced0 // keep self;
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self = f self // {
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newScope = scope: newScope (spliced // scope);
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callPackage = newScope spliced; # == self.newScope {};
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# N.B. the other stages of the package set spliced in are *not*
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# overridden.
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overrideScope = g: (makeScopeWithSplicing'
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{ inherit splicePackages newScope; }
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{ inherit otherSplices keep extra;
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f = lib.fixedPoints.extends g f;
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});
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packages = f;
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};
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in self;
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}
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