Contrib/0/rfc169 proof/out

experimental.nix

@@ -0,0 +1,8 @@
+let
+  nixpkgs = import ./. {};
+  inherit (nixpkgs) cmus;
+  inherit (nixpkgs.lib) rfc0169Renamed;
+in {
+  cmus2 = (rfc0169Renamed cmus.override) { with_alsa = false; };
+  cmus3 = (rfc0169Renamed cmus.override) { alsaSupport = false; };
+}

lib/customisation.nix

@@ -7,7 +7,7 @@ let
     functionArgs isFunction mirrorFunctionArgs isAttrs setFunctionArgs
     optionalAttrs attrNames filter elemAt concatStringsSep sortOn take length
     filterAttrs optionalString flip pathIsDirectory head pipe isDerivation listToAttrs
-    mapAttrs seq flatten deepSeq warnIf isInOldestRelease extends
+    mapAttrs seq flatten deepSeq warnIf isInOldestRelease extends rfc0169Renamed
     ;
   inherit (lib.strings) levenshtein levenshteinAtMost;
 
@@ -107,15 +107,15 @@ rec {
     in
       if isAttrs result then
         result // {
-          override = overrideArgs;
+          override = rfc0169Renamed overrideArgs;
           overrideDerivation = fdrv: overrideResult (x: overrideDerivation x fdrv);
           ${if result ? overrideAttrs then "overrideAttrs" else null} = fdrv:
             overrideResult (x: x.overrideAttrs fdrv);
         }
       else if isFunction result then
         # Transform the result into a functor while propagating its arguments
         setFunctionArgs result (functionArgs result) // {
-          override = overrideArgs;
+          override = rfc0169Renamed overrideArgs;
         }
       else result);
 

lib/default.nix

@@ -63,6 +63,7 @@ let
 
     # linux kernel configuration
     kernel = callLibs ./kernel.nix;
+    rfc_0169 = callLibs ./rfc_0169.nix;
 
     inherit (builtins) add addErrorContext attrNames concatLists
       deepSeq elem elemAt filter genericClosure genList getAttr
@@ -166,5 +167,6 @@ let
       nixType imap;
     inherit (self.versions)
       splitVersion;
+    inherit (self.rfc_0169) rfc0169Renamed;
   });
 in lib

lib/rfc0169.json

@@ -0,0 +1,6 @@
+{
+  "with_alsa": [
+    "alsaSupport",
+    "withAlsa"
+  ]
+}

lib/rfc_0169.nix

@@ -0,0 +1,36 @@
+{ lib }:
+let
+  inherit (lib) functionArgs isAttrs getAttr hasAttr mapAttrsToList warn;
+
+  BACKWARD = builtins.fromJSON (builtins.readFile ./rfc0169.json);
+  FORWARD = builtins.listToAttrs (builtins.concatLists (mapAttrsToList (n: map (x: { name = x; value = n; })) BACKWARD));
+
+  # Since we don't know what was the original deprecated name used by the
+  # package (if any, really), we have to extend original signature with all
+  # known deprecated names.
+  #
+  # Which means that if before it had "alsaSupport", now override can also be
+  # called with "withAlsa". And let's not bring what will happen if somebody
+  # provides both. Goal is to keep old code working, not preventing user from
+  # defying warnings and doing something stupid.
+  mkExtraArgs = name: value:
+    if hasAttr name BACKWARD
+    then map (n: { name = n; value = value; }) (getAttr name BACKWARD)
+    else [];
+  renamePair = name: value:
+    let renamed = lib.getAttr name FORWARD;
+        warning = "Feature parameter '" + name + "' is deprecated in favor of '" + renamed + "'.";
+    in if hasAttr name FORWARD && hasAttr (getAttr name FORWARD) BACKWARD
+    then warn warning { name = renamed; inherit value; }
+    else { inherit name value; };
+in {
+  rfc0169Renamed = functor:
+    let oldArgs = functionArgs functor;
+        patch = builtins.listToAttrs (builtins.concatLists (mapAttrsToList mkExtraArgs oldArgs));
+    in if patch == {}
+       then functor # nothing to do.
+       else args': functor (if isAttrs args' then builtins.listToAttrs (mapAttrsToList renamePair args') else args');
+}
+
+
+

pkgs/applications/audio/cmus/default.nix

@@ -1,7 +1,7 @@
 { config, lib, stdenv, fetchFromGitHub, fetchpatch, ncurses, pkg-config
 , libiconv, CoreAudio, AudioUnit, VideoToolbox
 
-, alsaSupport ? stdenv.isLinux, alsa-lib ? null
+, with_alsa ? stdenv.isLinux, alsa-lib ? null
 # simple fallback for everyone else
 , aoSupport ? !stdenv.isLinux, libao ? null
 , jackSupport ? false, libjack ? null
@@ -53,7 +53,7 @@ let
 
   opts = [
     # Audio output
-    (mkFlag alsaSupport       "CONFIG_ALSA=y"       alsa-lib)
+    (mkFlag with_alsa       "CONFIG_ALSA=y"       alsa-lib)
     (mkFlag aoSupport         "CONFIG_AO=y"         libao)
     (mkFlag jackSupport       "CONFIG_JACK=y"       libjack)
     (mkFlag samplerateSupport "CONFIG_SAMPLERATE=y" libsamplerate)