[Pythonmac-SIG] PackageManager and Packages

[Sarwat Khan]

I've been trying to follow the Package Manager thread and it just keeps 
piling up and up :P I want to share some thoughts and a suggestion.

First of all, I don't like the idea of having executable code in 
plists. However I'm not a fan of receipts either. I remember on FreeBSD 
installing XFree86, installing emacs (which can work fine without X), 
upgrading XFree86 (possibly by uninstalling and installing again), and 
then finding out that my emacs was screwed. Since X was optional the 
libraries were removed out from under emacs, and it was screwed. Just 
my $.02 there; I'd something smarter.

When it comes to comparing versions, I've given up on using "1.0.1b2" 
and just started using integers and incrementing them. Apple's agvtool 
(Apple Generic Versioning) defines two version numbers for a product, 
the 'version' and the 'marketing version.' The version is a floating 
point number that is always increasing, like 85.5. The marketing 
version is a string like 1.0.1 b2 and is what the end-user sees. It's 
MUCH easier to deal with projects that use solid numbers for versions - 
2 dimensional version numbers are much easier to compare than 5 
dimensional ones :P

The other thing is that it'd be a lot easier to uninstall packages if 
they weren't so messy about being installed. This might require a 
change to Python and how it handles stuff but honestly that's a good 
thing. zipimport is a great addition as it lets you specify one easily 
maintainable directory structure for a package, the only downside is 
that it has to be hard coded into a path (or a .pth I guess). But 
that's an example. Perhaps there's more we can do to Python's 
under-used import hooks to make package management easier to deal with; 
it's best to make the system better at accommodating the needs of a 
better Package Manager before we write a better Package Manager (like 
how it'd be great if distutils supported uninstall).

Why can't an entire Python package be installed as a Mac OS X style 
bundle?

foobar.pyndle/
     Contents/
         MacOS/
             foobar.dylib
             <compiled os x binaries>
         Win32/
             <compiled win32 binaries>
             foobar.dll
         Resources/
             python2.3/
                 site-packages/
                     foobar.py

For now, I think you can hack together a .pth that adds enough entries 
together to make a bundle work. But this would make package removal 
much easier, although it doesn't directly solve the issue of 
dependancies. Perhaps Package Manager can maintain a tree based on 
meta-info provided with each bundle, and rebuild it if it detects it 
being out of sync.

{sarwat khan : http://sarwat.net}