[Python-Dev] Draft PEP: "Simplified Package Layout and Partitioning"

[Terry Reedy]

On 7/20/2011 1:04 PM, P.J. Eby wrote:

>> This part worries me slightly. Imagine a program as such:
>>
>> datagen.py
>> json/foo.js
>> json/bar.js
>>
>> datagen.py uses the files in json/ to generate sample data for a
>> database. In datagen.py is the following code:
>>
>> try:
>> import json
>> except ImportError:
>> import simplejson as json

While reading the PEP, I worried about this standard usage too but 
missed the scenario you imagined. Good catch.

> A possible mitigation would be to require that get_subpath() only return
> a directory name if that directory in fact contains importable modules
> somewhere. This is actually discussed a bit later as an open issue under
> "Implementation Notes", indicating that iter_modules() has this issue as
> well.

If one actually wants to create a bare-as-possible empty module, one can 
do that now either with a directory containing an empty __init__.py or, 
even cleaner, imp.new_module. So there is no need for the new mechanism 
to ever duplicate either ;-). So +1 on improving back-compatibility.

-- 
Terry Jan Reedy