Ensure consistent file ordering in observatory tarball

runtime/tools/create_archive.py

 # Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 #
 # This python script creates a tar archive and a C++ source file which contains
 # the tar archive as an array of bytes.
 
 import os
 import sys
 from os.path import join, splitext
@@ skipping 114 matching lines @@
     for dirname, dirnames, filenames in os.walk(options.client_root):
       # strip out all dot files.
       filenames = [f for f in filenames if not f[0] == '.']
       dirnames[:] = [d for d in dirnames if not d[0] == '.']
       for f in filenames:
         src_path = os.path.join(dirname, f)
         if (os.path.isdir(src_path)):
             continue
         files.append(src_path)
 
+    # Ensure consistent file ordering for reproducible builds.
+    files.sort()
+
     # Write out archive.
     makeArchive(options.tar_output,
                 options.client_root,
                 options.compress,
                 files)
 
     # Read it back in.
     with open(options.tar_output, 'rb') as tar_file:
       tar_archive = tar_file.read()
 
     # Write CC file.
     writeCCFile(options.output,
                 options.outer_namespace,
                 options.inner_namespace,
                 options.name,
                 tar_archive)
     return 0
 
   except Exception, inst:
     sys.stderr.write('create_resources.py exception\n')
     sys.stderr.write(str(inst))
     sys.stderr.write('\n')
     return -1
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv))