From 9ab1df5b6875e9acc22f5bc4358373104af1e790 Mon Sep 17 00:00:00 2001
From: Max Howell <max@methylblue.com>
Date: Mon, 19 Mar 2012 14:11:25 +0000
Subject: [PATCH] If no formula but multiple kegs, advise resolution

In this case the user will simply have to delete all but one keg in order to use the command that uses ARGV.kegs.

Refs Homebrew/homebrew#11050.
---
 Library/Homebrew/cmd/unlink.rb  |  2 +-
 Library/Homebrew/extend/ARGV.rb | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/Library/Homebrew/cmd/unlink.rb b/Library/Homebrew/cmd/unlink.rb
index bf1f137e0d..12b0377815 100644
--- a/Library/Homebrew/cmd/unlink.rb
+++ b/Library/Homebrew/cmd/unlink.rb
@@ -1,6 +1,6 @@
 module Homebrew extend self
   def unlink
-    raise FormulaUnspecifiedError if ARGV.named.empty?
+    raise KegUnspecifiedError if ARGV.named.empty?
 
     ARGV.kegs.each do |keg|
       print "Unlinking #{keg}... "
diff --git a/Library/Homebrew/extend/ARGV.rb b/Library/Homebrew/extend/ARGV.rb
index 25d19e2e7f..b994df6587 100644
--- a/Library/Homebrew/extend/ARGV.rb
+++ b/Library/Homebrew/extend/ARGV.rb
@@ -16,6 +16,7 @@ module HomebrewArgvExtension
   end
 
   def kegs
+    rack = nil
     require 'keg'
     require 'formula'
     @kegs ||= downcased_unique_named.collect do |name|
@@ -47,6 +48,15 @@ module HomebrewArgvExtension
         Keg.new(linked_keg_ref.realpath)
       end
     end
+  rescue FormulaUnavailableError
+    if rack
+      raise <<-EOS.undent
+        Multiple kegs installed to #{rack}
+        Please remove all but one and then try again.
+      EOS
+    else
+      raise
+    end
   end
 
   # self documenting perhaps?