How to solve AttributeError when importing igraph?

Question

When I import the igraph package in my project, I get an AttributeError. This only happens in the project directory:

[12:34][~]$ python2
Python 2.7.1 (r271:86832, Apr 15 2011, 12:09:10) 
[GCC 4.5.2 20110127 (prerelease)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import igraph
>>> 

[12:34][~]$ cd projectdir/
[12:34][projectdir]$ python2
Python 2.7.1 (r271:86832, Apr 15 2011, 12:09:10) 
[GCC 4.5.2 20110127 (prerelease)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import igraph
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/site-packages/igraph/__init__.py", line 42, in <module>
    import gzip
  File "/usr/lib/python2.7/gzip.py", line 36, in <module>
    class GzipFile(io.BufferedIOBase):
AttributeError: 'module' object has no attribute 'BufferedIOBase'
>>>

There is no file igraph.py in the project directory:

[12:34][projectdir]$ ls -alR | grep igraph | wc -l
0

And there are no circular imports.

How can I solve this error?

Answer 1

Most likely, there is a module io in ~/projectdir or one of the paths the project configures. The gzip module imported by igraph starts with

import io

and expect the built-in io module, not your project's one. Look for an io directory, or io.py or io.pyc. It can also help to scrutinize sys.path for any other directories (maybe outside of ~/projectdir) that might contain modules named io.