Test for whether inside virtualenv does not work if directory is symlinked

[tcorbettclark]

The following test for whether IPython is running inside a virtualenv does not work if the python executable and the VIRTUAL_ENV variable are at the same place but one is at a symlinked path to the other:

ipython/IPython/core/interactiveshell.py

Line 719 in 5bf4949

if sys.executable.startswith(os.environ['VIRTUAL_ENV']):

Discovered when using invewrapper, but problem appears more generic: pew-org/pew#8

tcorbettclark@cmed1:~$ python -c "import IPython; print(IPython.sys_info())"
{'codename': 'An Afternoon Hack',
 'commit_hash': '7c2ea3a',
 'commit_source': 'installation',
 'default_encoding': 'UTF-8',
 'ipython_path': '/home/tcorbettclark/.virtualenvs/ice/local/lib/python2.7/site-packages/IPython',
 'ipython_version': '1.1.0',
 'os_name': 'posix',
 'platform': 'Linux-3.5.0-42-generic-x86_64-with-Ubuntu-12.10-quantal',
 'sys_executable': '/home/tcorbettclark/.virtualenvs/ice/bin/python',
 'sys_platform': 'linux2',
 'sys_version': '2.7.3 (default, Sep 26 2013, 16:35:25) \n[GCC 4.7.2]'}
tcorbettclark@cmed1:~$ 

[minrk]

Can you try #4489?