python - Symbol not found: __PyCodecInfo_GetIncrementalDecoder

Question

Since updating from Homebrew Python 2.7.11 (from 2.7.10) I'm suddenly unable to test register my package on PyPi from the PyCharm IDE console.

Running (as an "External Tool")

python -B setup.py register -r pypitest

I now get

Traceback (most recent call last):
  File "setup.py", line 22, in <module>
    from setuptools import setup
  File "/usr/local/lib/python2.7/site-packages/setuptools/__init__.py", line 12, in <module>
    from setuptools.extension import Extension
  File "/usr/local/lib/python2.7/site-packages/setuptools/extension.py", line 8, in <module>
    from .dist import _get_unpatched
  File "/usr/local/lib/python2.7/site-packages/setuptools/dist.py", line 16, in <module>
    from setuptools.depends import Require
  File "/usr/local/lib/python2.7/site-packages/setuptools/depends.py", line 6, in <module>
    from setuptools import compat
  File "/usr/local/lib/python2.7/site-packages/setuptools/compat.py", line 17, in <module>
    import httplib
  File "/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/httplib.py", line 80, in <module>
    import mimetools
  File "/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/mimetools.py", line 6, in <module>
    import tempfile
  File "/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/tempfile.py", line 32, in <module>
    import io as _io
  File "/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/io.py", line 51, in <module>
    import _io
ImportError: dlopen(/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload/_io.so, 2): Symbol not found: __PyCodecInfo_GetIncrementalDecoder
  Referenced from: /usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload/_io.so
  Expected in: flat namespace
 in /usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload/_io.so

Process finished with exit code 1

I'm not sure how to proceed. I only get this issue if I execute from within my IDE's console. If I do it directly at the system command line (Terminal on OS X) I have no problems.

---

OS X 10.11.3; Homebrew Python 2.7.11; PyCharm 5.0.3

Answer 1

tl;dr: Fix this issue by doing one of the following:

• type hash -r python, OR
• log out and log in.

EDIT: An answer to my related question makes it clear what's happening here. When you install a new version of python, you may need to run hash -r python to tell bash to reset the "cached" location to the python executable.

In my case, I was typing python, which was on my $PATH at /usr/local/bin/python. But bash was still using the old cache location /usr/bin/python. So, the old executable was called, but the new path was provided to python in sys.argv[0]. This means that the old executable was running, but the new sys.executable value caused all the wrong modules to get loaded (including the io module).

---

I'm having the same problem. I installed python 2.7.11 via an installer from Python.org. Strangely, the issue seems to be related to some subtle difference between how OSX launches python when I invoke it from the shell using the full path vs. using just the word python.

So, for me, this works (invoking python via the full path /usr/local/bin/python):

$ which python
/usr/local/bin/python
$ /usr/local/bin/python -c "import io"
$

... but this doesn't:

$ python -c "import io"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/io.py", line 51, in <module>
    import _io
ImportError: dlopen(/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload/_io.so, 2): Symbol not found: __PyCodecInfo_GetIncrementalDecoder
  Referenced from: /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload/_io.so
  Expected in: flat namespace
 in /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload/_io.so

So, as a workaround, you can try doing the same thing.

Elsewhere, I've posted a separate question about this puzzling behavior. Maybe somehow merely calling python invokes some strange mix of the 2.7.11 executable with the 2.7.10 dylibs??