command-processor.rb: return executable file only

* lib/shell/command-processor.rb (Shell::CommandProcessor#find_system_command):
  return executable file only, should ignore directories and
  unexecutable files.  [ruby-core:57235] [Bug #8918]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42961 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,4 +1,8 @@
-Tue Sep 17 15:53:20 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Tue Sep 17 15:54:03 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/shell/command-processor.rb (Shell::CommandProcessor#find_system_command):
+	  return executable file only, should ignore directories and
+	  unexecutable files.  [ruby-core:57235] [Bug #8918]
 
 	* lib/test/unit/assertions.rb (Test::Unit::Assertions#assert_throw):
 	  assertion for throw.  MiniTest::Assertions#assert_throws discards

lib/shell/command-processor.rb

@@ -369,7 +369,12 @@ class Shell
 
       for p in @shell.system_path
         path = join(p, command)
-        if FileTest.exist?(path)
+        begin
+          st = File.stat(path)
+        rescue SystemCallError
+          next
+        else
+          next unless st.executable? and !st.directory?
           @system_commands[command] = path
           return path
         end