From b4da3bb88b04329984cf56540f41956299c9cdc0 Mon Sep 17 00:00:00 2001
From: Nathan Zadoks <nathan@nathan7.eu>
Date: Sun, 7 Feb 2016 16:39:39 +0100
Subject: [PATCH 1/2] buildRubyGem: ensure gem versions don't get misparsed

Without this, every nix-env --upgrade replaces ruby with an
arbitrary gem, which makes Ruby unusuable from user environments.
---
 pkgs/development/interpreters/ruby/build-ruby-gem/default.nix | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/pkgs/development/interpreters/ruby/build-ruby-gem/default.nix b/pkgs/development/interpreters/ruby/build-ruby-gem/default.nix
index c5b9fba37aa0..fc9f0656cd98 100644
--- a/pkgs/development/interpreters/ruby/build-ruby-gem/default.nix
+++ b/pkgs/development/interpreters/ruby/build-ruby-gem/default.nix
@@ -32,7 +32,9 @@ lib.makeOverridable (
 , platform ? "ruby"
 , ruby ? defs.ruby
 , stdenv ? ruby.stdenv
-, namePrefix ? "${ruby.name}" + "-"
+, namePrefix ? (let
+    rubyName = builtins.parseDrvName ruby.name;
+  in "${rubyName.name}${rubyName.version}-")
 , buildInputs ? []
 , doCheck ? false
 , meta ? {}

From c998447a13e8f97f2cfce648d019a26ee5c87bba Mon Sep 17 00:00:00 2001
From: Nathan Zadoks <nathan@nathan7.eu>
Date: Sun, 7 Feb 2016 16:40:43 +0100
Subject: [PATCH 2/2] buildRubyGem: pass the gem version through into the
 derivation name

---
 pkgs/development/interpreters/ruby/build-ruby-gem/default.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkgs/development/interpreters/ruby/build-ruby-gem/default.nix b/pkgs/development/interpreters/ruby/build-ruby-gem/default.nix
index fc9f0656cd98..cc1f85de19d3 100644
--- a/pkgs/development/interpreters/ruby/build-ruby-gem/default.nix
+++ b/pkgs/development/interpreters/ruby/build-ruby-gem/default.nix
@@ -91,7 +91,7 @@ stdenv.mkDerivation (attrs // {
     ++ lib.optional stdenv.isDarwin darwin.libobjc
     ++ buildInputs;
 
-  name = attrs.name or (namePrefix + gemName);
+  name = attrs.name or "${namePrefix}${gemName}-${version}";
 
   inherit src;