Link new tapped formula during brew update

Required me to spoil tap's code. All in the name of DRY! Alas!

Library/Homebrew/cmd/tap.rb

@@ -21,21 +21,28 @@ module Homebrew extend self
     raise "Already tapped!" if tapd.directory?
     abort unless system "git clone https://github.com/#{user}/homebrew-#{repo} #{tapd}"
 
-    gitignores = (HOMEBREW_LIBRARY/"Formula/.gitignore").read.split rescue []
+    files = []
+    tapd.find_formula{ |file| files << Pathname.new("#{user}-#{repo}").join(file) }
+    link_tap_formula(files)
+  end
 
-    cd HOMEBREW_LIBRARY/"Formula"
-    tapd.find_formula do |relative_pathname|
-      # using the system ln is the only way to get relative symlinks
-      system "ln -s ../Taps/#{user}-#{repo}/#{relative_pathname} 2>/dev/null"
-      if $?.success?
-        gitignores << relative_pathname.basename.to_s
-      else
-        opoo "#{relative_pathname.basename('.rb')} conflicts"
+  def link_tap_formula formulae
+    ignores = (HOMEBREW_LIBRARY/"Formula/.gitignore").read.split rescue []
+
+    cd HOMEBREW_LIBRARY/"Formula" do
+      formulae.each do |formula|
+        # using the system ln is the only way to get relative symlinks
+        system "ln -s ../Taps/#{formula} 2>/dev/null"
+        if $?.success?
+          ignores << formula.basename.to_s
+        else
+          opoo "#{formula.basename('.rb')} conflicts"
+        end
       end
     end
 
     tf = Tempfile.new("brew-tap")
-    tf.write(gitignores.uniq.join("\n"))
+    tf.write(ignores.uniq.join("\n"))
     tf.close
     mv tf.path, "#{HOMEBREW_LIBRARY}/Formula/.gitignore"
   end

Library/Homebrew/cmd/update.rb

@@ -1,3 +1,5 @@
+require 'cmd/tap'
+
 module Homebrew extend self
 
   def update
@@ -14,6 +16,7 @@ module Homebrew extend self
     master_updater.pull!
     report.merge!(master_updater.report)
 
+    new_files = []
     Dir["Library/Taps/*"].each do |tapd|
       cd tapd do
         updater = Updater.new
@@ -23,6 +26,7 @@ module Homebrew extend self
         end
       end
     end
+    Homebrew.link_tap_formula(report.new_tapped_formula)
 
     if report.empty?
       puts "Already up-to-date."
@@ -117,6 +121,14 @@ class Report < Hash
 #    dump_deleted_commands
   end
 
+  def new_tapped_formula
+    fetch(:A, []).map do |path|
+      case path when %r{^Library/Taps(/\w+-\w+/.*)}
+        Pathname.new($1)
+      end
+    end.compact
+  end
+
   def select_formula key
     fetch(key, []).map do |path|
       case path when %r{^Library/Formula}