[Python-Dev] Import semantics?

[Eric V. Smith]

On 6/8/2012 6:41 PM, Ethan Furman wrote:
> Dan Stromberg wrote:
>> On Fri, Jun 8, 2012 at 3:16 PM, Ethan Furman wrote:
>> Dan Stromberg wrote:
>>> Did the import semantics change in cpython 3.3a4?
>>>
>>> I used to be able to import treap.py even though I had a treap
>>> directory in my cwd.  With 3.3a4, I have to rename the treap
>>> directory to see treap.py.
>>
>> Check out PEP 420 -- Implicit Namespace Packages
>> [http://www.python.org/dev/peps/pep-0420/]
>>
>>
>> Am I misinterpreting this?  It seems like according to the PEP, I
>> should have still been able to import treap.py despite having a
>> treap/.  But I couldn't; I had to rename treap/ to treap-dir/ first.
>>
>> During import processing, the import machinery will continue to
>> iterate over each directory in the parent path as it does in Python
>> 3.2. While looking for a module or package named "foo", for each
>> directory in the parent path:
>>
>>         * If <directory>/foo/__init__.py is found, a regular package is
>>           imported and returned.
>>         * If not, but <directory>/foo.{py,pyc,so,pyd} is found, a module
>>           is imported and returned. The exact list of extension varies
>>           by platform and whether the -O flag is specified. The list
>>           here is representative.
>>         * If not, but <directory>/foo is found and is a directory, it is
>>           recorded and the scan continues with the next directory in the
>>           parent path.
>>         * Otherwise the scan continues with the next directory in the
>>           parent path.
> 
> I do not understand PEP 420 well enough to say if this is intentional or
> a bug -- thoughts?

I missed the beginning of this discussion and I need some more details.
What directories are on sys.path, where do treap.py and treap/ appear in
them, and is there an __init__.py in treap? At first blush it sounds
like it should continue working.

If you (Dan?) could re-create this in a small example and open a bug,
that would be great.

Eric.