Arbitrarily large output can't be used in an exception.

lib/cros_build_lib.py

 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Common python commands used by various build scripts."""
 
 import inspect
 import os
 import re
 import subprocess
@@ skipping 92 matching lines @@
       break
 
   if file_handle: file_handle.close()
 
   # If they asked for an exit_code, give it to them on success or failure
   if exit_code:
     return proc.returncode
 
   # If the command (and all retries) failed, handle error result
   if proc.returncode != 0 and not error_ok:
+    if output:
+      print >> sys.stderr, output
+      sys.stderr.flush()
+
     error_info = ('Command "%r" failed.\n' % (cmd) +
-                  (error_message or error or output or ''))
+                  (error_message or error or ''))
     if log_to_file: error_info += '\nOutput logged to %s' % log_to_file
     raise RunCommandException(error_info)
 
   # return final result
   return output
 
 
 def RunCommandCaptureOutput(cmd, print_cmd=True, cwd=None, input=None,
                             enter_chroot=False,
                             combine_stdout_stderr=True,
@@ skipping 230 matching lines @@
   return os.path.join(GetCrosUtilsPath(source_dir_path), 'bin')
 
 
 def IsInsideChroot():
   """Returns True if we are inside chroot."""
   return os.path.exists('/etc/debian_chroot')
 
 
 # TODO(sosa): Remove once all callers use method.
 CROSUTILS_DIRECTORY = GetCrosUtilsPath(True)