[Python-Dev] Proposal for a modified import mechanism. (original) (raw)

Prabhu Ramachandran Prabhu Ramachandran prabhu@cyberwaveindia.com
Sun, 11 Nov 2001 10:05:13 +0530

"GMcM" == Gordon McMillan <gmcm@hypernet.com> writes:

GMcM> [Prabhu works on knee.py]

>> it also fixes a bug where the parent package is an extension
>> module.

GMcM> Python provides no support for an extension module being a
GMcM> package parent module. More precisely, I think the fact that
GMcM> an extension module can be made to behave like a package
GMcM> parent module is an accident. There is special code in
GMcM> import for modules named __init__, and the code is bypassed
GMcM> for extension modules.

GMcM> I suspect you'd have to provide a pretty strong
GMcM> justification before this would become supported behavior.

I guess this was unclear. My addition is extremely simple and does not do anything new. Here is an illustration

import knee import Numeric.array Traceback (most recent call last): File "", line 1, in ? File "/usr/local/lib/python2.1/knee.py", line 17, in import_hook m = load_tail(q, tail) File "/usr/local/lib/python2.1/knee.py", line 68, in load_tail m = import_module(head, mname, m) File "/usr/local/lib/python2.1/knee.py", line 97, in import_module parent and parent.path) AttributeError: 'Numeric' module has no attribute 'path'

Point is, there is a line in knee.py (line 97 that assumes that there is a path attribute for the passed parent. However, if parent is an extension module there is none. So I simply modified it. Here is the diff.

$ diff knee.py /usr/local/lib/python2.1/knee.py 98,101c98 < except (ImportError, AttributeError): < # extension modules dont have a path attribute. < # caching failures. < sys.modules[fqname] = None

except ImportError:

In fact that is all I changed in knee.py! Which is why I said the changes are very small. Maybe I should have shown a patch but the mail was already long.

prabhu