Environment variables getting lost

[tobbez]

I noticed this while trying to run ftp-grab with seesaw and wpull installed in a virtualenv.

When using wpull_bootstrap, find_executable succeeds, but seesaw later fails when trying to call it, raising an exception:

Traceback (most recent call last):
  File "./wpull_bootstrap", line 9, in <module>
    import wpull.__main__
ImportError: No module named 'wpull'

When removing "./wpull_bootstrap" from the list passed to seesaw.util.find_executable, thereby falling back to finding wpull in path, the call to find_executable still succeeds, and later seesaw fails with:

Traceback (most recent call last):
  File "[...]/venv/lib/python3.4/site-packages/seesaw/pipeline.py", line 61, in _enqueue_with_except
    task.enqueue(item)
  File "[...]/venv/lib/python3.4/site-packages/seesaw/externalprocess.py", line 189, in enqueue
    self.process(item)
  File "[...]/venv/lib/python3.4/site-packages/seesaw/externalprocess.py", line 207, in process
    p.run()
  File "[...]/venv/lib/python3.4/site-packages/seesaw/externalprocess.py", line 142, in run
    self.pipe = tornado.process.Subprocess(*self.args, **self.kwargs)
  File "[...]/venv/lib/python3.4/site-packages/tornado/process.py", line 240, in __init__
    self.proc = subprocess.Popen(*args, **kwargs)
  File "/usr/lib64/python3.4/subprocess.py", line 859, in __init__
    restore_signals, start_new_session)
  File "/usr/lib64/python3.4/subprocess.py", line 1457, in _execute_child
    raise child_exception_type(errno_num, err_msg)
FileNotFoundError: [Errno 2] No such file or directory: 'wpull'

These messages seem to imply that the environment variables setup by virtualenv are getting lost somewhere, but I'm not sure where.