Allow underscore in github version numbers.

2 files changed, 7 insertions, 3 deletions

diff --git a/Library/Formula/ack.rb b/Library/Formula/ack.rb
index 4be7335b7..a9e9899f8 100644
--- a/Library/Formula/ack.rb
+++ b/Library/Formula/ack.rb
@@ -2,7 +2,6 @@ require 'formula'
 
 class Ack < Formula
   url "https://github.com/petdance/ack/tarball/1.93_02"
-  version '1.93_02'
   md5 'b468ce41a949fd957dc9b6aee74782e9'
   homepage 'http://betterthangrep.com/'
 
diff --git a/Library/Homebrew/extend/pathname.rb b/Library/Homebrew/extend/pathname.rb
index f61a69e09..8b690a258 100644
--- a/Library/Homebrew/extend/pathname.rb
+++ b/Library/Homebrew/extend/pathname.rb
@@ -108,15 +108,20 @@ class Pathname
       stem=self.stem
     end
 
-    # github tarballs are special
-    # we only support numbered tagged downloads
+    # github tarballs, like v1.2.3
     %r[github.com/.*/tarball/v?((\d\.)+\d+)$].match to_s
     return $1 if $1
 
+    # dashed version
     # eg. github.com/isaacs/npm/tarball/v0.2.5-1
     %r[github.com/.*/tarball/v?((\d\.)+\d+-(\d+))$].match to_s
     return $1 if $1
 
+    # underscore version
+    # eg. github.com/petdance/ack/tarball/1.93_02
+    %r[github.com/.*/tarball/v?((\d\.)+\d+_(\d+))$].match to_s
+    return $1 if $1
+
     # eg. boost_1_39_0
     /((\d+_)+\d+)$/.match stem
     return $1.gsub('_', '.') if $1