[Python-Dev] Status of packaging in 3.3

[Chris McDonough]

On 06/21/2012 10:30 AM, Nick Coghlan wrote:
>> A tool to generate an OS-specific system package from a Python library
>> project should be unrelated to a Python distribution *installer*. Instead,
>> you'd use related tools that understood how to unpack the distribution
>> packaging format to build one or more package structures. The resulting
>> structures will be processed and then eventually installed by native OS
>> install tools.  But the Python distribution installer (e.g easy_install,
>> pip, or some future similar tool) would just never come into play to create
>> those structures.  The Python distribution installer and the OS-specific
>> build tool might share code to introspect and unpack files from the
>> packaging format, but they'd otherwise have nothing to do with one another.
>>
>> This seems like the most reasonable separation of concerns to me anyway, and
>> I'd be willing to work on the code that would be shared by both the
>> Python-level installer and by OS-level packaging tools.
>
> Right, but if the standard library grows a dist installer (and I think
> it eventually should), we're going to need to define how it should
> behave when executed with the *system* Python.
>
> That will give at least 3 mechanisms for Python code to get onto a system:
>
> 1. Python dist ->  converter ->  system package ->  system Python path
>
> 2. Python dist ->  system Python installer ->  system Python path
>
> 3. Python dist ->  venv Python installer ->  venv Python path
>
> While I agree that path 2 should be discouraged for production
> systems, I don't think it should be prevented altogether (since it can
> be very convenient on personal systems).

I'm not sure under what circumstance 2 and 3 wouldn't do the same thing. 
  Do you have a concrete idea?

> As far as the scope of the packaging utilities and what they can
> install goes, I think the distutils2 folks have done a pretty good job
> of defining that with their static metadata format:
> http://alexis.notmyidea.org/distutils2/setupcfg.html#files

Yeah definitely a good start.

- C