[Python-Dev] PEP 376 - Open questions

[glyph at divmod.com]

On 03:28 am, eric at trueblade.com wrote:
>>Eventually, I'd like PEP 376 to support system packagers too. So for 
>>example, if you did "apt-get install python-pyqt4", then running "pip 
>>install python-pyqt4" should return without installing anything .. as 
>>RECORD will be part of the .deb previously installed. As for 
>>generating the RECORD file, I vote for generating it during install 
>>time (w/ absolute paths).
>
>I think we should explicitly not support this. What if pip and apt-get 
>(or rpm, or others) install the same package in different places 
>because of system conventions (/usr vs. /usr/local vs. /opt, say)? 
>There's no way we're ever going to get this right, and it's not worth 
>complicating our lives over it.

As I understand it, the point of the PEP is just to *provide the 
information* that the package installers need to get it right, not to 
actually implement the interaction with system package managers.
>Seriously: Is there some real world use case I'm missing? Does any 
>existing install system support this?

System package managers already provide .egg-info metadata, so this is 
hardly unprecedented.  The antecedent of your "this" is somewhat 
ambiguous, so I'm not sure if any package manager provides the exact 
feature that you have in mind.  If you're talking about different 
package managers installing stuff on the same system, you can look a bit 
farther afield: 'alien' allows you to install RPM and debian packages on 
the same system, with some reconciliation of dependencies and other 
metadata.