Prevent tapped symlinks showing up in git status

The symlinks taps write to Formula show up in git status, but this trick prevents this. brew-(un)tap maintain a .gitignore in Formula that contains all the symlinks brew-tap creates.

We add the .gitignore to the root .gitignore and TADA! Magic.

1 files changed, 11 insertions, 2 deletions

diff --git a/Library/Homebrew/cmd/untap.rb b/Library/Homebrew/cmd/untap.rb
index 78778e6fc..80d38934b 100644
--- a/Library/Homebrew/cmd/untap.rb
+++ b/Library/Homebrew/cmd/untap.rb
@@ -1,4 +1,5 @@
 require 'cmd/tap' # for Pathname.recursive_formula
+require 'tempfile'
 
 module Homebrew extend self
   def untap
@@ -7,11 +8,19 @@ module Homebrew extend self
 
     raise "No such tap!" unless tapd.directory?
 
+    gitignores = (HOMEBREW_PREFIX/"Library/Formula/.gitignore").read.split rescue []
+
     tapd.find_formula do |pn|
-      pn = HOMEBREW_REPOSITORY/"Library/Formula"/pn.basename
+      bn = pn.basename.to_s
+      pn = HOMEBREW_REPOSITORY/"Library/Formula"/bn
       pn.delete if pn.symlink? and pn.realpath.to_s =~ %r[^#{tapd.realpath}]
+      gitignores.delete(bn)
     end
-
     rm_rf tapd
+
+    tf = Tempfile.new("brew-untap")
+    tf.write(gitignores.join("\n"))
+    tf.close
+    mv tf.path, "#{HOMEBREW_PREFIX}/Library/Formula/.gitignore"
   end
 end