Use a subprocess wrapper that will throw if a command returns a non-zero result code

abp_rewrite.py

 #!/usr/bin/env python
 # coding: utf-8
 
 # This Source Code is subject to the terms of the Mozilla Public License
 # version 2.0 (the "License"). You can obtain a copy of the License at
 # http://mozilla.org/MPL/2.0/.
 
 import sys, os, subprocess, utils
 
 def doRewrite(files, args):
   application = utils.ensureJSShell()
 
   env = {
     'LD_LIBRARY_PATH': os.path.relpath(os.path.dirname(application)),
   }
 
   baseDir = os.path.dirname(utils.__file__)
   command = [
     application, os.path.join(baseDir, 'jshydra.js'),
     os.path.join(baseDir, 'scripts', 'abprewrite.js'),
     '--arg', ' '.join(args)
   ] + files
-  result, dummy = subprocess.Popen(command, stdout=subprocess.PIPE, env=env).communicate()
-  result = result.replace('\r', '')
-  return result
+  return subprocess.check_output(command, env=env).replace('\r', '')
 
 if __name__ == '__main__':
   try:
     scriptArgsStart = sys.argv.index('--arg')
   except ValueError:
     scriptArgsStart = len(sys.argv)
   print doRewrite(sys.argv[1:scriptArgsStart], sys.argv[scriptArgsStart + 1:])