Use the proper sys.path in build/print_python_deps.py

build/print_python_deps.py

 #!/usr/bin/env python
 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Prints all non-system dependencies for the given module.
 
 The primary use-case for this script is to genererate the list of python modules
 required for .isolate files.
 """
@@ skipping 64 matching lines @@
                       help='The python module to analyze.')
   parser.add_argument('--root', default='.',
                       help='Directory to make paths relative to.')
   parser.add_argument('--output',
                       help='Write output to a file rather than stdout.')
   parser.add_argument('--whitelist', default=[], action='append',
                       dest='whitelists',
                       help='Recursively include all non-test python files '
                       'within this directory. May be specified multiple times.')
   options = parser.parse_args()
-  sys.path.append(os.path.dirname(options.module))
+  # Replace the path entry for print_python_deps.py with the one for the given
+  # module.
+  sys.path[0] = os.path.dirname(options.module)

[jbudorick, 2016/11/10 19:41:02]

Do we want anything else in sys.path at all? I'm concerned that this won't work
in some cases if the modules don't resolve to something in the options.module
path.

[agrieve, 2016/11/10 19:45:35]

If you clear out sys.path, then normal system import don't work (e.g. import
os). I did a local test with a file that just prints sys.path:

PYTHONPATH=a python hi.py
['/usr/local/google/home/agrieve/ssd/git/clankium1/src',
'/usr/local/google/home/agrieve/ssd/git/clankium1/src/a', '/usr/lib/python2.7',
'/usr/lib/python2.7/plat-x86_64-linux-gnu', '/usr/lib/python2.7/lib-tk',
'/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload',
'/usr/local/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages',
'/usr/lib/python2.7/dist-packages/PILcompat',
'/usr/lib/python2.7/dist-packages/gtk-2.0', '/usr/lib/pymodules/python2.7',
'/usr/lib/python2.7/dist-packages/ubuntu-sso-client']

1st entry is module dir, 2nd is PYTHONPATH, remaining is system paths

[jbudorick, 2016/11/10 19:49:12]

I guess I'm concerned about the case where a module appends to sys.path then
imports something from that, but it conflicts with something on PYTHONPATH.
Maybe that's too much of a corner case for this script to worry about, though --
perhaps the responsibility for not passing the infra PYTHONPATH contents falls
on the infra side of the fence.

   imp.load_source('NAME', options.module)
 
   paths_set = _ComputePythonDependencies()
   for path in options.whitelists:
     paths_set.update(os.path.abspath(p) for p in _FindPythonInDirectory(path))
 
   paths = [os.path.relpath(p, options.root) for p in paths_set]
 
   normalized_cmdline = _NormalizeCommandLine(options)
   out = open(options.output, 'w') if options.output else sys.stdout
   with out:
     out.write('# Generated by running:\n')
     out.write('#   %s\n' % normalized_cmdline)
     for path in sorted(paths):
       out.write(path + '\n')
 
 
 if __name__ == '__main__':
   sys.exit(main())