Fixes Pathname.install(:foo => :bar) to work when File.exist?(:bar)

Library/Homebrew/extend/pathname.rb

@@ -3,14 +3,27 @@ require 'pathname'
 # we enhance pathname to make our code more readable
 class Pathname
   def install src
-    if src.is_a? Array
-      src.collect {|src| install src }
-    elsif src.is_a? Hash
-      src.each_pair do |name, new_name|
-        FileUtils.mv name, new_name
-        install new_name
+    case src
+    when Array
+      src.collect {|src| install_p(src) }
+    when Hash
+      src.collect {|src, new_basename| install_p(src, new_basename) }
+    else
+      install_p(src)
+    end
   end
+
+  def install_p src, new_basename = nil
+    if new_basename
+      new_basename = File.basename(new_basename) # rationale: see Pathname.+
+      dst = self+new_basename
     else
+      dst = self
+    end
+
+    src = src.to_s
+    dst = dst.to_s
+
     # if it's a symlink, don't resolve it to a file because if we are moving
     # files one by one, it's likely we will break the symlink by moving what
     # it points to before we move it
@@ -21,15 +34,14 @@ class Pathname
     if File.symlink? src
       # we use the BSD mv command because FileUtils copies the target and
       # not the link! I'm beginning to wish I'd used Python quite honestly!
-        raise unless Kernel.system 'mv', src, to_s and $? == 0
+      raise unless Kernel.system 'mv', src, dst
     else
       # we mv when possible as it is faster and you should only be using
       # this function when installing from the temporary build directory
-        FileUtils.mv src, to_s
-      end
-      src=Pathname.new src
-      return self+src.basename
+      FileUtils.mv src, dst
     end
+
+    return Pathname.new(dst)
   end
 
   # we assume this pathname object is a file obviously