[Pythonmac-SIG] Package Manager idea, adding a URL scheme

Jack Jansen Jack.Jansen at cwi.nl
Fri Oct 3 10:33:50 EDT 2003

On Friday, October 3, 2003, at 11:15 AM, Just van Rossum wrote:

> [Just]
>>> I don't think PackMan needs to be extensible to such an extent. Am
>>> I right that the current Python snippets only do version checks?
>>> Receipts would work just as well, provided we limit version
>>> checking to packages installed through PackMan. I think that's a
>>> reasonable constraint.
> [Jack]
>> No, receipts are specifically what I *don't* want. I want PackMan to
>> do actual tests of what is available.
> Apart from availability/version tests, we're going to _need_ receipts 
> if
> we want to support uninstalls.

You're absolutely right. The statement I really wanted to make above
was: "Using receipts for version testing is specifically what I *don't* 

>> The problem with receipts is that it causes a package manager to live
>> in a completely self-centered world: it knows about everything it
>> installed itself and nothing else. This means that if I'm an active
>> developer on package X I always have to go out of my way, because the
>> package manager doesn't know that I've built and installed it myself.
> I don't follow: if you're building/installing package X yourself, why
> would you then want to use PackMan for package X also? I see it pretty
> much as an either/or situation.

Not for package X but for dependent packages! Think of the following
scenario: you maintain package X, that is also in PackMan. Package Y
depends on package X but you don't maintain it. With a know-it-all
package manager you cannot install Y to use your X.

There are now three options open to you:
- trick the package manager to think that it installed X
- install every package depending on X by hand
- install two copies of X, one for your development and one
   through the package manager for use by dependent packages.

All of this falls under my favorite annoyance #4: things that
get in the way of developers for no obvious reason.

> PackMan is for end users. A certain amount of complexity for
> _developers_ seems pretty much unavoidable, and would be totally
> acceptable to me.
> I strongly feel that executing arbitrary code (even from a trusted
> source) is a big nono.

Uhm... How about arbitrary setup.py scripts included with packages?
Jack Jansen, <Jack.Jansen at cwi.nl>, http://www.cwi.nl/~jack
If I can't dance I don't want to be part of your revolution -- Emma 

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