os.path.dirname(__file__) doesn't exist?

Question

Possible Duplicate:
os.path.dirname(__file__) returns empty

A user of a Python script of mine said they got the following error:

Traceback (most recent call last):
File "MCManager.py", line 7, in <module>
os.chdir(os.path.dirname(__file__))
OSError: [Errno 2] No such file or directory: ''

How could the directory the script is in not exist? Is it a compatibility issue? I use the same OS and version as the one with the error, and haven't been able to replicate this.

Answer 1

It happens in Python 2 when executing a script from the same directory, e.g.

$ echo "print __file__" > /tmp/spam.py
$ python /tmp/spam.py 
/tmp/spam.py

$ cd /tmp
$ python spam.py
spam.py

One solution is to use os.path.abspath(__file__) in the code, so that you can always resolve the script directory in all three usage cases below:

$ cat /tmp/spam.py
import os
print os.path.dirname(os.path.abspath(__file__))

$ python /tmp/spam.py
/tmp

$ cd /tmp
$ python /tmp/spam.py
/tmp

$ python spam.py
/tmp