Non-existant module referenced in cpp_message.py

[dhirschfeld]

_net_proto2___python appears to no longer exist

https://github.com/google/protobuf/blob/e9c00d9dd0ac75dc3d1d140207939f11abe328b5/python/google/protobuf/internal/cpp_message.py#L39-L75

[gpshead]

internal/cpp_message.py is a leftover from the previous version that shouldn't exist anymore.

the code in internal/descriptor.py reads:

if api_implementation.Version() == 2:
from google.protobuf.pyext import _message
else:
from google.protobuf.internal import cpp_message

which should really just be edited to avoid the version check and be "from google.protobuf.pyext import _message". along will all other version checks using _message vs cpp_message in that file to get rid of cpp_message references all together.

If you set both of the magic environment variables before any google.protobuf imports, it works:

greg:~/sandbox/python/protobuf/python$ LD_LIBRARY_PATH=../src/.libs/ PYT
HONPATH=./ python
Python 2.7.6 (default, Mar 22 2014, 22:59:56)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.

from google.protobuf.internal import api_implementation
api_implementation.Type()
'python'
api_implementation.Version()
1
from google.protobuf import descriptor

greg:~/sandbox/python/protobuf/python$ LD_LIBRARY_PATH=../src/.libs/ PYTHONPATH=./ python
Python 2.7.6 (default, Mar 22 2014, 22:59:56)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.

import os
os.environ['PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION_VERSION'] = '2'
os.environ['PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION'] = 'cpp'
from google.protobuf.internal import api_implementation
api_implementation.Type()
'cpp'
api_implementation.Version()
2
from google.protobuf import descriptor
descriptor._message
<module 'google.protobuf.pyext._message' from 'google/protobuf/pyext/_message.so'>

there is something IMNSHO weird going on with the setup.py and how it builds _message.so and apparently _moves it outside of the build/lib.* tree afterwards (WTF?). But given we want to revisit our entire setup.py for this anyways... i expect that to be untangled in the future.