[Python-Dev] PEP 376 - Open questions

[P.J. Eby]

At 01:58 PM 7/8/2009 -0400, Eric Smith wrote:
>I really don't see this use case. Supporting multiple installers for 
>the same file (or even just trying to prevent two installers from 
>writing the same file)? Wouldn't you be better off just saying an 
>installer can't overwrite any existing file?
>
>Likewise, I don't see a use case for installing with one installer 
>and uninstalling with another.
>
>Put those two together, and the mechanism that an installer uses to 
>record what files it installed is a private implementation detail.

You'll have to ask Tarek about that.  As I've said in another email, 
if I were doing this for setuptools I'd just go and do it; it's 
already on my backlog of things to do.  The point of the PEP is to 
provide an uninstall facility for the distutils, and to expose those 
records via an API so that other tools can be built on top of it.

Whether anything other than distutils-based tools will actually use 
the format directly is entirely irrelevant to the PEP's merits, since 
bdist_* tools and platform-specific distutils installers may need to 
read or write the format.  Hence, a PEP is appropriate to describe a 
format and API for the distutils family of tools to operate on.

The specific proposed format is based on an existing de facto 
standard for installed package metadata, so that the many existing 
packaging tools based on that other format and existing APIs can 
easily read or write this data, and so that the API can also be used 
as a way to detect the presence of already-installed distributions of 
software -- even ones installed other ways.