Strange __import__() behavior

[Frank Miles]

I have an exceedingly simple function that does a "named import".
It works perfectly for one file "r"- and fails for the second "x".

If I reverse the order of being called, it is still "x" that fails,
and "r" still succeeds.

os.access() always reports that the file is readable (i.e. "true")

If I simply call up the python interpreter (python 2.6 - Debian stable)
and manually "import x" - there is no problem - both work. Similarly
typing the __import__("x") works when typed directly at the python
prompt. Both 'x' and 'r' pass pychecker with no errors. The same error
occurs with winpdb - the exception message says that the file could
not be found. 'file' reports that both files are text files, and there
aren't any strange file-access permissions/attributes.

Here's the function that is failing:

def named_import(fname, description) :
import os
pname= fname + '.py'
print "ENTRY FILE", pname, ": acces=", os.access(pname, os.R_OK)
try :
X=__import__(fname)
x= [ X.cmnds, X.variables ]
except ImportError :
print "failed"
return x

This is the first time I've needed to import a file whose name couldn't
be specified in the script, so there's a chance that I've done something
wrong, but it seems very weird that it works in the CL interpreter and
not in my script.

TIA for any hints or pointers to the relevant overlooked documentation!

-F

 

[Frank Miles]

I have an exceedingly simple function that does a "named import". It
works perfectly for one file "r"- and fails for the second "x".

If I reverse the order of being called, it is still "x" that fails, and
"r" still succeeds.

os.access() always reports that the file is readable (i.e. "true")

If I simply call up the python interpreter (python 2.6 - Debian stable)
and manually "import x" - there is no problem - both work. Similarly
typing the __import__("x") works when typed directly at the python
prompt. Both 'x' and 'r' pass pychecker with no errors. The same
error occurs with winpdb - the exception message says that the file
could not be found. 'file' reports that both files are text files, and
there aren't any strange file-access permissions/attributes.

Here's the function that is failing:

def named_import(fname, description) :
import os
pname= fname + '.py'
print "ENTRY FILE", pname, ": acces=", os.access(pname, os.R_OK)
try :
X=__import__(fname)
x= [ X.cmnds, X.variables ]
except ImportError :
print "failed"
return x

This is the first time I've needed to import a file whose name couldn't
be specified in the script, so there's a chance that I've done
something wrong, but it seems very weird that it works in the CL
interpreter and not in my script.

TIA for any hints or pointers to the relevant overlooked documentation!

I can't reproduce your problem on my configuration. Anyway, you should
note that if x.pyc and r.pyc are present, __import__ will try to import
them and not the files x.py and r.py. Try deleting x.pyc and r.pyc.

Kiuhnm

You are fast in replying! I nuked my query (within a few minutes of
posting) when I discovered the reason. Perhaps it persisted in some
domain.

I'd forgotten that the python script containing the described function was
not the file itself, but a link to the script. When I executed the script
(er, link to the script) - even with winpdb - apparently __import__
examined the directory where the actual file resided. In _that_
directory, only 'r' existed, no 'x'.

So thanks for trying, there was no way you (or anyone) could have seen
that the script was just a link to a script...

-F