Refactor brew missing

The heuristic for determining whether something is installed changes
from "f.installed?" to "f.rack.exist? and f.rack.subdirs.length > 0" in
order to properly consider outdated formulae.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Library/Homebrew/cmd/doctor.rb

@@ -764,9 +764,8 @@ def check_tmpdir
 def check_missing_deps
   return unless HOMEBREW_CELLAR.exist?
   s = Set.new
-  missing_deps = Homebrew.find_missing_brews(Homebrew.installed_brews)
-  missing_deps.each do |m|
-    s.merge m[1]
+  Homebrew.missing_deps(Homebrew.installed_brews).each do |_, deps|
+    s.merge deps
   end
 
   if s.length > 0 then <<-EOS.undent

Library/Homebrew/cmd/missing.rb

@@ -1,47 +1,41 @@
 require 'formula'
-require 'cmd/outdated'
 
 module Homebrew extend self
   def installed_brews
     formulae = []
     HOMEBREW_CELLAR.subdirs.each do |rack|
       f = Formula.factory rack.basename.to_s rescue nil
-      formulae << f if f and f.installed?
+      formulae << f if f and f.rack.exist? and f.rack.subdirs.length > 0
     end
     formulae
   end
 
-  def find_missing_brews top_level
-    # Names of outdated brews; they count as installed.
-    outdated = Homebrew.outdated_brews.collect{ |b| b.name }
-
-    brews = []
-    top_level.each do |f|
-      missing_deps = f.recursive_deps.map{ |g| g.name }.uniq.reject do |dep_name|
-        Formula.factory(dep_name).installed? or outdated.include?(dep_name)
-      end
+  def missing_deps ff
+    missing = {}
+    ff.each do |f|
+      missing_deps = f.recursive_deps.uniq.reject do |dep|
+          dep.rack.exist? and dep.rack.subdirs.length > 0
+        end
 
       unless missing_deps.empty?
-        brews << [f.name, missing_deps]
+        yield f.name, missing_deps if block_given?
+        missing[f.name] = missing_deps
       end
     end
-    brews
+    missing
   end
 
   def missing
     return unless HOMEBREW_CELLAR.exist?
 
-    formulae_to_check = if ARGV.named.empty?
+    ff = if ARGV.named.empty?
       installed_brews
     else
       ARGV.formulae
     end
 
-    missing_deps = find_missing_brews(formulae_to_check)
-    missing_deps.each do |d|
-      name = d[0]
-      missing = d[1]
-      print "#{name}: " if formulae_to_check.size > 1
+    missing_deps(ff) do |name, missing|
+      print "#{name}: " if ff.size > 1
       puts "#{missing * ' '}"
     end
   end