From 8dc1e05ff87d22f37261945e465cea23b1343c2c Mon Sep 17 00:00:00 2001
From: Martin Afanasjew <martin@afanasjew.de>
Date: Tue, 5 Jan 2016 01:09:54 +0100
Subject: [PATCH] utils: inject Ruby path when running Gems

Particularly the `bundler` Gem requires the right Ruby binary to be in
the PATH to work correctly if the Ruby binary used to run Homebrew is
overridden via `HOMEBREW_RUBY_PATH` and thus intentionally not prefixed
to the PATH (as that would affect formulae with a Ruby dependency).

The workaround here is to prefix this path only when a Gem is activated
via `Homebrew.install_gem_setup_path!` (currently used in `brew man`,
`brew style`, and `brew tests`).
---
 Library/Homebrew/utils.rb | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/Library/Homebrew/utils.rb b/Library/Homebrew/utils.rb
index bad26dfac1..d9a41b86dc 100644
--- a/Library/Homebrew/utils.rb
+++ b/Library/Homebrew/utils.rb
@@ -231,7 +231,12 @@ module Homebrew
 
   def self.install_gem_setup_path!(gem, version = nil, executable = gem)
     require "rubygems"
-    ENV["PATH"] = "#{Gem.user_dir}/bin:#{ENV["PATH"]}"
+
+    # Add Gem binary directory and (if missing) Ruby binary directory to PATH.
+    path = ENV["PATH"].split(File::PATH_SEPARATOR)
+    path.unshift(RUBY_BIN) if which("ruby") != RUBY_PATH
+    path.unshift("#{Gem.user_dir}/bin")
+    ENV["PATH"] = path.join(File::PATH_SEPARATOR)
 
     if Gem::Specification.find_all_by_name(gem, version).empty?
       ohai "Installing or updating '#{gem}' gem"