From dc16371e19d1a8bae153f6f44620667c0f542e73 Mon Sep 17 00:00:00 2001
From: Mike McQuaid <mike@mikemcquaid.com>
Date: Mon, 5 Jan 2015 19:14:55 +0000
Subject: [PATCH] utils: install_gem_setup_path! now checks PATH.

Check the executable is present to give a better error message if it isn't.

Closes Homebrew/homebrew#35541.
---
 Library/Homebrew/utils.rb | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/Library/Homebrew/utils.rb b/Library/Homebrew/utils.rb
index 16b2284323..d4d8288c62 100644
--- a/Library/Homebrew/utils.rb
+++ b/Library/Homebrew/utils.rb
@@ -120,12 +120,21 @@ module Homebrew
     HOMEBREW_REPOSITORY.cd { `git show -s --format="%cr" HEAD 2>/dev/null`.chuzzle }
   end
 
-  def self.install_gem_setup_path! gem
+  def self.install_gem_setup_path! gem, executable=gem
     require "rubygems"
     ENV["PATH"] = "#{Gem.user_dir}/bin:#{ENV["PATH"]}"
-    return if quiet_system "gem", "list", "--installed", gem
-    system "gem", "install", "--no-ri", "--no-rdoc",
-           "--user-install", gem
+
+    unless quiet_system "gem", "list", "--installed", gem
+      safe_system "gem", "install", "--no-ri", "--no-rdoc",
+                                    "--user-install", gem
+    end
+
+    unless which executable
+      odie <<-EOS.undent
+        The '#{gem}' gem is installed but couldn't find '#{executable}' in the PATH:
+        #{ENV["PATH"]}
+      EOS
+    end
   end
 end