Make it possible to override system ruby gems

svn path=/nixpkgs/trunk/; revision=25658

1 files changed, 30 insertions, 9 deletions

diff --git a/pkgs/development/interpreters/ruby/libs.nix b/pkgs/development/interpreters/ruby/libs.nix
index 57daafaef408..d0b6401abc29 100644
--- a/pkgs/development/interpreters/ruby/libs.nix
+++ b/pkgs/development/interpreters/ruby/libs.nix
@@ -1,12 +1,33 @@
-{stdenv, config, fetchurl, callPackage}:
+{stdenv, getConfig, fetchurl, callPackage}:
 
 let
-  generated = stdenv.lib.attrByPath [ "gems" "generated" ] (import ./generated.nix) config;
-  auto = generated merged;
-  patches = callPackage ./patches.nix { } gems;
-  overwrites = callPackage ./overwrites.nix { } gems;
-  merged = stdenv.lib.mapAttrs gem auto.gems;
-  gem = callPackage ./gem.nix { inherit patches overwrites; };
-  gems = merged // auto.aliases;
+  inherit (stdenv.lib) fold optional;
+  gemsMergeableFun = { generatedFuns ? [], patchFuns ? [], overrideFuns ? [] }:
+  let
+    generatedAttrs = map (f: f customGems) generatedFuns;
+    generatedGems = map (a: a.gems) generatedAttrs;
+    gem = callPackage ./gem.nix {
+      patches = map (f: callPackage f { inherit gems; }) patchFuns;
+      overrides = map (f: callPackage f { }) overrideFuns;
+    };
+    customGems = stdenv.lib.mapAttrs gem (fold (x: y: x // y) { } generatedGems);
+    gems = fold (x: y: x // y) customGems (map (a: a.aliases) generatedAttrs);
+  in
+  gems // {
+    merge = { generated ? null, patches ? null, overrides ? null }:
+      gemsMergeableFun {
+        generatedFuns = generatedFuns ++ optional (generated != null) generated;
+        patchFuns = patchFuns ++ optional (patches != null) patches;
+        overrideFuns = overrideFuns ++ optional (overrides != null) overrides;
+      };
+  };
 in
-gems
+((gemsMergeableFun { }).merge {
+  generated = import ./generated.nix;
+  patches = import ./patches.nix;
+  overrides = import ./overrides.nix;
+}).merge {
+  generated = getConfig [ "gems" "generated" ] null;
+  patches = getConfig [ "gems" "patches" ] null;
+  overrides = getConfig [ "gems" "overrides" ] null;
+}