changing sys.path

Andrea Crotti andrea.crotti.0 at gmail.com
Fri Feb 10 15:51:20 CET 2012


Ok now it's getting really confusing, I tried a small example to see 
what is the real behaviour,
so I created some package namespaces (where the __init__.py declare the 
namespace package).

   /home/andrea/test_ns:
   total used in directory 12 available 5655372
   drwxr-xr-x 3 andrea andrea 4096 Feb 10 14:46 a.b
   drwxr-xr-x 3 andrea andrea 4096 Feb 10 14:46 a.c
   -rw-r--r-- 1 andrea andrea  125 Feb 10 14:46 test.py

   /home/andrea/test_ns/a.b:
   total 8
   drwxr-xr-x 3 andrea andrea 4096 Feb 10 14:47 a
   -rw-r--r-- 1 andrea andrea   56 Feb 10 14:35 __init__.py

   /home/andrea/test_ns/a.b/a:
   total 8
   drwxr-xr-x 2 andrea andrea 4096 Feb 10 14:47 b
   -rw-r--r-- 1 andrea andrea   56 Feb 10 14:35 __init__.py

   /home/andrea/test_ns/a.b/a/b:
   total 12
   -rw-r--r-- 1 andrea andrea  25 Feb 10 14:36 api.py
   -rw-r--r-- 1 andrea andrea 153 Feb 10 14:37 api.pyc
   -rw-r--r-- 1 andrea andrea  56 Feb 10 14:35 __init__.py

   /home/andrea/test_ns/a.c:
   total 8
   drwxr-xr-x 3 andrea andrea 4096 Feb 10 14:47 a
   -rw-r--r-- 1 andrea andrea   56 Feb 10 14:35 __init__.py

   /home/andrea/test_ns/a.c/a:
   total 8
   drwxr-xr-x 2 andrea andrea 4096 Feb 10 14:47 c
   -rw-r--r-- 1 andrea andrea   56 Feb 10 14:35 __init__.py

   /home/andrea/test_ns/a.c/a/c:
   total 12
   -rw-r--r-- 1 andrea andrea  20 Feb 10 14:36 api.py
   -rw-r--r-- 1 andrea andrea 148 Feb 10 14:38 api.pyc
   -rw-r--r-- 1 andrea andrea  56 Feb 10 14:35 __init__.py


So this test.py works perfectly:
import sys
sys.path.insert(0, 'a.c')
sys.path.insert(0, 'a.b')

from a.b import api as api_ab

from a.c import api as api_ac

While just mixing the order:
import sys
sys.path.insert(0, 'a.b')

from a.b import api as api_ab

sys.path.insert(0, 'a.c')
from a.c import api as api_ac

Doesn't work anymore

[andrea at precision test_ns]$ python2 test.py
Traceback (most recent call last):
   File "test.py", line 7, in <module>
     from a.c import api as api_ac
ImportError: No module named c



Am I missing something/doing something stupid?



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