diff --git a/pkgs/lib/misc.nix b/pkgs/lib/misc.nix
index 32390b0d192..bd57d2b6518 100644
--- a/pkgs/lib/misc.nix
+++ b/pkgs/lib/misc.nix
@@ -317,6 +317,40 @@ rec {
   mergeAttrsByFuncDefaults = foldl mergeAttrByFunc { inherit mergeAttrBy; };
   mergeAttrsByFuncDefaultsClean = list: removeAttrs (mergeAttrsByFuncDefaults list) ["mergeAttrBy"];
 
+  # merge attrs based on version key into mkDerivation args, see mergeAttrBy to learn about smart merge defaults
+  #
+  # This function is best explained by an example:
+  #
+  #     {version ? "2.0"} :
+  #
+  #     mkDerivation (mergeAttrsByVersion "package-name" version 
+  #       { # version specific settings
+  #         "git" = { src = ..; preConfigre = "autogen.sh"; buildInputs = [automake autoconf libtool];  };
+  #         "2.0" = { src = ..; };
+  #       }
+  #       {  // shared settings
+  #          buildInputs = [ common build inputs ];
+  #          meta = { .. }
+  #       }
+  #     )
+  #
+  # Please note that e.g. Eelco Dolstra usually prefers having one file for
+  # each version. On the other hand there are valuable additional design goals
+  #  - readability
+  #  - do it once only
+  #  - try to avoid duplication
+  #
+  # Marc Weber and Michael Raskin sometimes prefer keeping older
+  # versions around for testing and regression tests - as long as its cheap to
+  # do so.
+  #
+  # Very often it just happens that the "shared" code is the bigger part.
+  # Then using this function might be appropriate.
+  #
+  # Be aware that its easy to cause recompilations in all versions when using this function
+  mergeAttrsByVersion = name: version: attrsByVersion: base:
+    mergeAttrsByFuncDefaultsClean [ { name = "${name}-${version}"; } base (maybeAttr version (throw "bad version ${version} for ${name}") attrsByVersion)];
+
   # sane defaults (same name as attr name so that inherit can be used)
   mergeAttrBy = # { buildInputs = concatList; [...]; passthru = mergeAttr; [..]; }
     listToAttrs (map (n : nameValuePair n lib.concat)