Clean up lockfiles

Library/Homebrew/cmd/cleanup.rb

@@ -10,7 +10,10 @@ module Homebrew extend self
     if ARGV.named.empty?
       cleanup_cellar
       cleanup_cache
-      rm_DS_Store unless ARGV.dry_run?
+      unless ARGV.dry_run?
+        cleanup_lockfiles
+        rm_DS_Store
+      end
     else
       ARGV.formulae.each { |f| cleanup_formula(f) }
     end
@@ -80,6 +83,14 @@ module Homebrew extend self
     end
   end
 
+  def cleanup_lockfiles
+    candidates = HOMEBREW_CACHE_FORMULA.children
+    lockfiles  = candidates.select { |f| f.file? && f.extname == '.brewing' }
+    lockfiles.select(&:readable?).each do |file|
+      file.open.flock(File::LOCK_EX | File::LOCK_NB) and file.unlink
+    end
+  end
+
   def rm_DS_Store
     system "find #{HOMEBREW_PREFIX} -name .DS_Store -delete 2>/dev/null"
   end