From 14eea491b82663117e9a40a65b01a86b9549ee03 Mon Sep 17 00:00:00 2001
From: Michael Raskin <7c6f434c@mail.ru>
Date: Tue, 29 Jun 2010 22:18:49 +0000
Subject: Adding Redstore HTTP RDF/SPARQL server

svn path=/nixpkgs/trunk/; revision=22428
---
 pkgs/lib/misc.nix | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

(limited to 'pkgs/lib/misc.nix')

diff --git a/pkgs/lib/misc.nix b/pkgs/lib/misc.nix
index 32b30ee2fbf..f3eb7e8bf8f 100644
--- a/pkgs/lib/misc.nix
+++ b/pkgs/lib/misc.nix
@@ -94,6 +94,11 @@ rec {
   composedArgsAndFun = f: foldArgs defaultMerge f {};
 
   
+  # shortcut for attrByPath ["name"] default attrs
+  maybeAttrNullable = name: default: attrs:
+    if attrs == null then default else 
+    if (__hasAttr name attrs) then (__getAttr name attrs) else default;
+
   # shortcut for attrByPath ["name"] default attrs
   maybeAttr = name: default: attrs:
     if (__hasAttr name attrs) then (__getAttr name attrs) else default;
@@ -204,8 +209,8 @@ rec {
     innerClosePropagation 
       (ready ++ [(head list)])
       ((tail list) 
-         ++ (maybeAttr "propagatedBuildInputs" [] (head list))
-	 ++ (maybeAttr "propagatedBuildNativeInputs" [] (head list)));
+         ++ (maybeAttrNullable "propagatedBuildInputs" [] (head list))
+	 ++ (maybeAttrNullable "propagatedBuildNativeInputs" [] (head list)));
 
   closePropagation = list: (uniqList {inputList = (innerClosePropagation [] list);});
 
-- 
cgit 1.4.1