import bug

Jon Clements joncle at googlemail.com
Sat Oct 31 16:31:40 CET 2009


On Oct 31, 3:12 pm, kj <no.em... at please.post> wrote:
> I'm running into an ugly bug, which, IMHO, is really a bug in the
> design of Python's module import scheme.  Consider the following
> directory structure:
>
> ham
> |-- __init__.py
> |-- re.py
> `-- spam.py
>
> ...with the following very simple files:
>
> % head ham/*.py
> ==> ham/__init__.py <==
>
> ==> ham/re.py <==
>
> ==> ham/spam.py <==
> import inspect
>
> I.e. only ham/spam.py is not empty, and it contains the single line
> "import inspect".
>
> If I now run the innocent-looking ham/spam.py, I get the following
> error:
>
> % python26 ham/spam.py
> Traceback (most recent call last):
>   File "ham/spam.py", line 1, in <module>
>     import inspect
>   File "/usr/local/python-2.6.1/lib/python2.6/inspect.py", line 35, in <module>
>     import string
>   File "/usr/local/python-2.6.1/lib/python2.6/string.py", line 122, in <module>
>     class Template:
>   File "/usr/local/python-2.6.1/lib/python2.6/string.py", line 116, in __init__
>     'delim' : _re.escape(cls.delimiter),
> AttributeError: 'module' object has no attribute 'escape'
>
> or, similarly,
>
> % python3 ham/spam.py
> Traceback (most recent call last):
>   File "ham/spam.py", line 1, in <module>
>     import inspect
>   File "/usr/local/python-3.0/lib/python3.0/inspect.py", line 36, in <module>
>     import string
>   File "/usr/local/python-3.0/lib/python3.0/string.py", line 104, in <module>
>     class Template(metaclass=_TemplateMetaclass):
>   File "/usr/local/python-3.0/lib/python3.0/string.py", line 98, in __init__
>     'delim' : _re.escape(cls.delimiter),
> AttributeError: 'module' object has no attribute 'escape'
>
> My sin appears to be having the (empty) file ham/re.py.  So Python
> is confusing it with the re module of the standard library, and
> using it when the inspect module tries to import re.
>
> I've tried a lot of things to appease Python on this one, including
> a liberal sprinkling of "from __future__ import absolute_import"
> all over the place (except, of course, in inspect.py, which I don't
> control), but to no avail.
>
> I also pored over pp. 149-151 of Beazley's Python Essential Reference
> (4th ed.) on anything that would shed light on this problem, and
> again, nothing.
>
> I give up: what's the trick?  (Of course, renaming ham/re.py is
> hardly "the trick."  It's rather Procrustes' Bed.)
>
> BTW, it is hard for me to imagine of an argument that could convince
> me that this is not a design bug, and a pretty ugly one at that.
> But, as they say, "hope springs eternal": is there a PEP on the
> subject?  (I know that there's a PEP on absolute_import, but since
> absolute_import appears to be absolutely ineffectual here, I figure
> I must look elsewhere for enlightenment.)
>
> TIA!
>
> kynn

You can shift the location of the current directory further down the
search path.
Assuming sys.path[0] is ''...

Python 2.6.2 (release26-maint, Apr 19 2009, 01:56:41)
[GCC 4.3.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.path = sys.path[1:] + ['']
>>> import spam
>>> spam.__file__
'spam.pyc'

hth
Jon.
hth,

Jon.








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