From 3c18d16f48560b15962a5c26cdfc1c6d0a1afe53 Mon Sep 17 00:00:00 2001
From: Tomas Valent <equivalent@eq8.eu>
Date: Wed, 13 Jan 2016 16:59:44 +0000
Subject: [PATCH] fix NoMethodError: undefined method `zero?' for nil:NilClass

---
 lib/yui/compressor.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/yui/compressor.rb b/lib/yui/compressor.rb
index 515ccf8..8d706df 100644
--- a/lib/yui/compressor.rb
+++ b/lib/yui/compressor.rb
@@ -98,7 +98,7 @@ def compress(stream_or_string)
           tempfile.close!
         end
 
-        if $?.exitstatus.zero?
+        if $?.exitstatus && $?.exitstatus.zero?
           output
         else
           # Bourne shells tend to blow up here when the command fails, usually