diff --git a/doc/functions.xml b/doc/functions.xml index 908e9571ed6..f5fb90921bf 100644 --- a/doc/functions.xml +++ b/doc/functions.xml @@ -85,9 +85,70 @@ in ... +
+ <pkg>.overrideAttrs + + + The function overrideAttrs allows overriding the + attribute set passed to a stdenv.mkDerivation call, + producing a new derivation based on the original one. + This function is available on all derivations produced by the + stdenv.mkDerivation function, which is most packages + in the nixpkgs expression pkgs. + + + + Example usage: + + helloWithDebug = pkgs.hello.overrideAttrs (oldAttrs: rec { + separateDebugInfo = true; +}); + + + + In the above example, the separateDebugInfo attribute is + overriden to be true, thus building debug info for + helloWithDebug, while all other attributes will be + retained from the original hello package. + + + + The argument oldAttrs is conventionally used to refer to + the attr set originally passed to stdenv.mkDerivation. + + + + + Note that separateDebugInfo is processed only by the + stdenv.mkDerivation function, not the generated, raw + Nix derivation. Thus, using overrideDerivation will + not work in this case, as it overrides only the attributes of the final + derivation. It is for this reason that overrideAttrs + should be preferred in (almost) all cases to + overrideDerivation, i.e. to allow using + sdenv.mkDerivation to process input arguments, as well + as the fact that it is easier to use (you can use the same attribute + names you see in your Nix code, instead of the ones generated (e.g. + buildInputs vs nativeBuildInputs, + and involves less typing. + + + +
+ +
<pkg>.overrideDerivation + + You should prefer overrideAttrs in almost all + cases, see its documentation for the reasons why. + overrideDerivation is not deprecated and will continue + to work, but is less nice to use and does not have as many abilities as + overrideAttrs. + + + Do not use this function in Nixpkgs as it evaluates a Derivation before modifying it, which breaks package abstraction and removes diff --git a/lib/customisation.nix b/lib/customisation.nix index efe82d78660..3e6e279824b 100644 --- a/lib/customisation.nix +++ b/lib/customisation.nix @@ -56,16 +56,18 @@ rec { ff = f origArgs; overrideWith = newArgs: origArgs // (if builtins.isFunction newArgs then newArgs origArgs else newArgs); in - if builtins.isAttrs ff then (ff // - { override = newArgs: makeOverridable f (overrideWith newArgs); - overrideDerivation = fdrv: - makeOverridable (args: overrideDerivation (f args) fdrv) origArgs; - }) - else if builtins.isFunction ff then - { override = newArgs: makeOverridable f (overrideWith newArgs); - __functor = self: ff; - overrideDerivation = throw "overrideDerivation not yet supported for functors"; - } + if builtins.isAttrs ff then (ff // { + override = newArgs: makeOverridable f (overrideWith newArgs); + overrideDerivation = fdrv: + makeOverridable (args: overrideDerivation (f args) fdrv) origArgs; + ${if ff ? overrideAttrs then "overrideAttrs" else null} = fdrv: + makeOverridable (args: (f args).overrideAttrs fdrv) origArgs; + }) + else if builtins.isFunction ff then { + override = newArgs: makeOverridable f (overrideWith newArgs); + __functor = self: ff; + overrideDerivation = throw "overrideDerivation not yet supported for functors"; + } else ff; diff --git a/pkgs/stdenv/generic/default.nix b/pkgs/stdenv/generic/default.nix index e71c2f770b9..489b6cbb426 100644 --- a/pkgs/stdenv/generic/default.nix +++ b/pkgs/stdenv/generic/default.nix @@ -227,6 +227,7 @@ let outputs = outputs'; } else { })))) ( { + overrideAttrs = f: mkDerivation (attrs // (f attrs)); # The meta attribute is passed in the resulting attribute set, # but it's not part of the actual derivation, i.e., it's not # passed to the builder and is not a dependency. But since we