nixpkgs/pkgs/lib/customisation.nix

41 lines
1.4 KiB
Nix
Raw Normal View History

{
/* `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 overriden
according to the function `f'. This function is called with the
original derivation attributes.
`overrideDerivation' allows certain "ad-hoc" customisation
scenarios (e.g. in ~/.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. */
overrideDerivation = drv: f:
let
# Filter out special attributes.
attrs = removeAttrs drv ["meta" "passthru" "outPath" "drvPath"];
newDrv = derivation (attrs // (f drv));
in newDrv //
{ meta = if drv ? meta then drv.meta else {};
passthru = if drv ? passthru then drv.passthru else {};
};
}